EDAIC Part I — European Diploma in Anaesthesiology and Intensive Care — Questions and Answers

Question 1: What is the recommended approach when a 'walking epidural' technique is desired for labor analgesia?

Low-dose bupivacaine 0.0625% with intrathecal fentanyl via CSE (Correct answer)
Epidural lidocaine 2% with epinephrine
High-concentration bupivacaine without opioid
Epidural morphine alone

Correct answer: Low-dose bupivacaine 0.0625% with intrathecal fentanyl via CSE

CSE with low-dose local anesthetic and lipid-soluble opioid provides analgesia with preserved motor function, allowing ambulation when monitored safely.

Question 2: According to current ESAIC/ESA fasting guidelines for elective surgery in adults, what is the minimum recommended fasting time for clear fluids (water, black tea, black coffee)?

30 minutes
2 hours (Correct answer)
4 hours
6 hours

Correct answer: 2 hours

Current evidence-based guidelines (ESAIC, ERAS, ASA) recommend a minimum of 2 hours fasting for clear fluids and 6 hours for solids and milk in healthy adults undergoing elective surgery. Clear fluids empty rapidly from the stomach; prolonged fasting beyond 2 hours for fluids is unnecessary and associated with increased patient discomfort, dehydration, and insulin resistance.

Question 3: What is the primary mechanism by which volatile anesthetics cause myocardial depression?

Reducing intracellular calcium availability and sensitization (Correct answer)
Blocking sodium channels in myocytes
Inhibiting myosin ATPase directly
Blocking beta-1 adrenoceptors

Correct answer: Reducing intracellular calcium availability and sensitization

Volatile anesthetics impair calcium release from the sarcoplasmic reticulum and reduce myofilament calcium sensitivity, depressing myocardial contractility.

Question 4: Which ion channel is responsible for the pacemaker current (If) in the sinoatrial node?

Delayed rectifier potassium channel
HCN (hyperpolarization-activated cyclic nucleotide-gated) channel (Correct answer)
L-type calcium channel
Fast sodium channel

Correct answer: HCN (hyperpolarization-activated cyclic nucleotide-gated) channel

The funny current (If) flows through HCN channels activated by hyperpolarization, carrying a mixed Na+/K+ inward current that drives spontaneous phase 4 depolarization.

Question 5: Which of the following statements best describes the primary mechanism of action of tranexamic acid (TXA) in a trauma patient with massive hemorrhage?

It inhibits the conversion of fibrinogen to fibrin.
It directly activates platelets to enhance primary hemostasis.
It prevents the breakdown of existing clots by inhibiting plasminogen activation. (Correct answer)
It provides concentrated clotting factors to accelerate the coagulation cascade.

Correct answer: It prevents the breakdown of existing clots by inhibiting plasminogen activation.

Tranexamic acid is a synthetic lysine analog. Its primary mechanism is antifibrinolytic. It competitively inhibits the activation of plasminogen to plasmin, the enzyme responsible for clot degradation (fibrinolysis). [28, 29] By preventing plasmin from binding to fibrin, it stabilizes formed clots and reduces bleeding, particularly in the context of trauma-induced coagulopathy where hyperfibrinolysis is common. [25, 33] It does not directly activate platelets, provide clotting factors, or inhibit fibrin formation.

Question 6: During transcranial Doppler (TCD) monitoring of a patient 7 days after a subarachnoid hemorrhage, the mean flow velocity in the middle cerebral artery (MCA) is measured at 180 cm/s. The mean flow velocity in the ipsilateral extracranial internal carotid artery (ICA) is 50 cm/s. What is the most likely interpretation of these findings?

Cerebral hyperemia
Normal cerebral blood flow
Severe cerebral vasospasm (Correct answer)
Intracranial hypertension

Correct answer: Severe cerebral vasospasm

These findings are indicative of cerebral vasospasm. The high MCA velocity (>120 cm/s is suggestive, >160cm/s is moderate, and >200cm/s is severe) points to arterial narrowing. To differentiate vasospasm from hyperemia (which also increases velocity), the Lindegaard ratio (MCA velocity / ICA velocity) is calculated. In this case, 180/50 = 3.6. A Lindegaard ratio greater than 3 is consistent with vasospasm, and a ratio between 3 and 6 suggests mild-to-moderate vasospasm. Hyperemia would have a ratio less than 3.

Question 7: A patient with idiopathic pulmonary arterial hypertension (mPAP 55 mmHg, PVR 12 Wood units) requires urgent thoracotomy for haemoptysis. Intraoperatively, after induction, RV systolic pressure by TOE rises to 90 mmHg and the patient develops hypotension (MAP 52 mmHg). Which combination of interventions is MOST appropriate?

Volume loading with 1 L crystalloid, metaraminol boluses, and PEEP 10 cmH₂O
Milrinone infusion, systemic vasodilation with GTN, and permissive hypoxia
Norepinephrine infusion, inhaled nitric oxide 20 ppm, and avoidance of hypoxia/hypercarbia/acidosis (Correct answer)
Vasopressin infusion, sodium nitroprusside, and PaCO₂ target of 35–40 mmHg

Correct answer: Norepinephrine infusion, inhaled nitric oxide 20 ppm, and avoidance of hypoxia/hypercarbia/acidosis

In acute RV failure complicating severe PAH, the priority is to: (1) maintain systemic vascular resistance to preserve RV coronary perfusion pressure (norepinephrine); (2) selectively reduce PVR without systemic vasodilation (inhaled NO at 20 ppm achieves this — it is inactivated by haemoglobin before reaching the systemic circulation); and (3) aggressively prevent all triggers of pulmonary vasoconstriction (hypoxia, hypercarbia, acidosis). Volume loading risks RV dilation and septal shift worsening LV output. High PEEP markedly increases PVR. Sodium nitroprusside causes systemic vasodilation, worsening hypotension and RV ischaemia. GTN similarly drops systemic BP. Permissive hypoxia is absolutely contraindicated as it is a powerful pulmonary vasoconstrictor.

Question 8: Critical incident reporting systems in anaesthesia departments encourage reporting of 'near miss' events. What is the primary rationale for analysing near misses rather than focusing only on adverse outcomes?

Near misses require mandatory financial compensation to the patient
Near misses are legally equivalent to adverse events in all European jurisdictions
Near misses expose system vulnerabilities before harm reaches the patient, enabling preventive system changes (Correct answer)
Near misses occur less frequently than actual adverse events and are therefore more informative

Correct answer: Near misses expose system vulnerabilities before harm reaches the patient, enabling preventive system changes

Near misses ('close calls') are incidents where a harmful outcome was averted by chance or last-minute intervention. They are far more frequent than serious adverse events and share the same upstream causal factors. Analysing them identifies latent system failures before harm occurs — providing a low-cost, high-yield opportunity for system improvement. This is central to High Reliability Organisation (HRO) principles in healthcare.

Question 9: A patient with renal failure develops prolonged bleeding time with normal PT and aPTT. What is the most likely mechanism?

Warfarin effect
Thrombocytopenia
Factor VII deficiency
Platelet dysfunction due to uremic toxins (Correct answer)

Correct answer: Platelet dysfunction due to uremic toxins

Uremia impairs platelet adhesion and aggregation by interfering with GPIb-von Willebrand factor interaction.

Question 10: During management of a patient with severe TBI (GCS 6, CT showing diffuse axonal injury), ICP is consistently 28 mmHg despite head positioning, sedation, osmotherapy with mannitol, and normoventilation (PaCO₂ 35–38 mmHg). CPP is 62 mmHg. You are considering decompressive craniectomy versus barbiturate coma. Which statement best reflects current evidence regarding these two options?

Both interventions have equivalent mortality benefit and should be chosen based on ICP magnitude alone
Decompressive craniectomy reduces ICP effectively but the DECRA and RESCUEicp trials showed conflicting results regarding functional outcomes, with RESCUEicp showing survival benefit but more survivors with severe disability (Correct answer)
Decompressive craniectomy is contraindicated in diffuse axonal injury without mass lesion
Barbiturate coma is preferred as it has superior evidence for improving neurological outcomes over decompressive craniectomy

Correct answer: Decompressive craniectomy reduces ICP effectively but the DECRA and RESCUEicp trials showed conflicting results regarding functional outcomes, with RESCUEicp showing survival benefit but more survivors with severe disability

The DECRA trial (2011) showed that early bifrontal decompressive craniectomy reduced ICP and ICU stay but was associated with worse functional outcomes at 6 months. The RESCUEicp trial (2016) evaluated craniectomy as a last-tier therapy and found a significant reduction in mortality (26.9% vs 48.9% at 6 months), but more survivors were left with severe disability or vegetative state. This nuance — reduced mortality but at a cost of increased disability — is the defining tension in TBI decompression decisions. Barbiturate coma has evidence for ICP reduction (Pentobarbital) but no proven neurological outcome benefit and carries significant risks (immunosuppression, cardiovascular depression). Decompressive craniectomy is not contraindicated in diffuse injury.

Question 11: During anaesthesia for a 4 kg neonate with a large left-to-right ventricular septal defect (VSD), you notice a sudden rise in EtCO₂ from 38 to 55 mmHg with unchanged ventilator settings, decreasing SpO₂, and worsening haemodynamics. Which physiological mechanism BEST explains this constellation of findings?

Inadvertent increase in inspired oxygen causing pulmonary vasoconstriction
Volatile agent-induced systemic vasodilation reducing left ventricular afterload and increasing Qp:Qs ratio
Acute endotracheal tube obstruction causing CO₂ retention and hypoxia
Reversal of shunt direction due to acute pulmonary hypertensive crisis increasing right-to-left flow (Correct answer)

Correct answer: Reversal of shunt direction due to acute pulmonary hypertensive crisis increasing right-to-left flow

A sudden rise in EtCO₂ combined with desaturation and haemodynamic compromise in a VSD patient suggests an acute pulmonary hypertensive crisis causing reversal of shunt direction (Eisenmenger physiology acutely). When pulmonary vascular resistance (PVR) acutely exceeds systemic vascular resistance (SVR), the left-to-right shunt reverses, producing right-to-left flow and systemic hypoxaemia. This also reduces effective pulmonary blood flow, causing CO₂ retention. ETT obstruction would not explain shunt reversal. Increased FiO₂ is a pulmonary vasodilator, not constrictor. Volatile-induced vasodilation would increase Qp:Qs but would not cause reversal or desaturation of this severity.

Question 12: When performing high-frequency jet ventilation (HFJV) for rigid bronchoscopy and subglottic tracheal stenosis resection, which physiological principle BEST explains adequate CO2 elimination despite tidal volumes smaller than anatomical dead space?

Continuous fresh gas flow washing out CO2 via mass convection alone
Increased functional residual capacity reducing dead space fraction
Asymmetric velocity profiles and augmented molecular diffusion (Taylor dispersion) (Correct answer)
Entrainment of ambient air increasing effective tidal volume above dead space

Correct answer: Asymmetric velocity profiles and augmented molecular diffusion (Taylor dispersion)

CO2 elimination during HFJV occurs through multiple mechanisms, but the most important at high frequencies with sub-dead-space tidal volumes is Taylor dispersion (augmented axial diffusion). Asymmetric turbulent velocity profiles create radial mixing, dramatically enhancing the effective diffusion coefficient for CO2 far beyond simple Fickian diffusion. Entrainment does occur with open-circuit HFJV and contributes, but it does not fully explain CO2 clearance at all frequencies. Mass convection (bulk flow) is the dominant mechanism only at lower HFJV frequencies.

Question 13: In a trauma patient receiving massive transfusion, rotational thromboelastometry (ROTEM) demonstrates an isolated, markedly prolonged EXTEM lysis index at 30 minutes (LI30 <85%) with a normal FIBTEM and INTEM. What does this pattern indicate and what is the most appropriate intervention?

Hyperfibrinolysis as the dominant abnormality — treat with tranexamic acid (Correct answer)
Severe hypothermia-induced coagulopathy — treat with warming and calcium chloride
Factor XIII deficiency causing weak cross-linking — treat with Factor XIII concentrate
Disseminated intravascular coagulation with consumption coagulopathy — treat with FFP and platelets

Correct answer: Hyperfibrinolysis as the dominant abnormality — treat with tranexamic acid

An LI30 <85% on EXTEM (or LI60 <85%) indicates fibrinolysis occurring within 30 minutes of clot formation, a hallmark of hyperfibrinolysis. This pattern is distinct from DIC (which shows prolonged CTs and low MCF) and Factor XIII deficiency (which prolongs clot retraction but not early lysis). Hyperfibrinolysis in trauma is driven by massive tissue plasminogen activator release from endothelium. The CRASH-2 and MATTERS trials demonstrated mortality benefit of tranexamic acid (TXA) in trauma haemorrhage, and ROTEM-guided TXA use is standard practice. TXA is most effective when given within 3 hours of injury. Isolated hyperfibrinolysis does not require FFP or platelets.

Question 14: The volume of distribution (Vd) of a highly lipophilic drug is characteristically:

Much greater than total body water, often >10 L/kg (Correct answer)
Equal to plasma volume (0.05 L/kg)
Less than total body water (0.6 L/kg)
Limited to extracellular fluid volume (0.2 L/kg)

Correct answer: Much greater than total body water, often >10 L/kg

Highly lipophilic drugs distribute extensively into fat and tissue, resulting in very large apparent volumes of distribution often many times greater than actual body volume.

Question 15: A competent adult Jehovah's Witness patient has signed an advance refusal of blood products and verbally reaffirms this refusal in the anaesthetic room before emergency laparotomy for a ruptured ectopic pregnancy. The surgeon believes transfusion will be necessary to prevent death. What is the ethically and legally correct action?

Obtain an emergency court order permitting transfusion
Transfuse immediately — preservation of life overrides refusal in an emergency
Respect the patient's refusal and proceed without blood products, using all available blood conservation strategies (Correct answer)
Delay surgery until a psychiatrist certifies the patient lacks capacity

Correct answer: Respect the patient's refusal and proceed without blood products, using all available blood conservation strategies

A competent adult's advance refusal of treatment — when made with full understanding of the consequences — is legally binding and must be respected even if it results in the patient's death. Overriding the refusal would constitute unlawful battery. The duty of the anaesthetist is to respect autonomy while employing maximum blood conservation techniques (cell salvage, haemostatic agents, permissive hypotension). The ethical framework here is respect for patient autonomy, which outweighs paternalistic beneficence.

Question 16: A patient on warfarin requires emergency reversal. Which agent provides the most rapid and complete reversal?

Protamine sulfate
4-factor prothrombin complex concentrate (4F-PCC) (Correct answer)
Fresh frozen plasma
Vitamin K IV

Correct answer: 4-factor prothrombin complex concentrate (4F-PCC)

4-factor PCC provides immediate reversal of vitamin K antagonists with a smaller volume and faster effect than FFP.

Question 17: A patient with severe aortic stenosis undergoes spinal anaesthesia. Despite a 1.5 L crystalloid pre-load, blood pressure drops to 70/40 mmHg. Phenylephrine is given but cardiac output falls further. Which physiological explanation best accounts for this deterioration?

Phenylephrine's pure α1-agonism increased SVR, reducing the pressure gradient across the fixed stenotic valve and critically reducing stroke volume
Phenylephrine caused reflex bradycardia, reducing diastolic filling time and worsening subendocardial ischaemia in the hypertrophied ventricle (Correct answer)
Spinal-induced venodilation reduced preload below the steep portion of the Frank-Starling curve in a non-compliant ventricle
Phenylephrine precipitated coronary vasospasm by stimulating α1-receptors on epicardial coronary vessels

Correct answer: Phenylephrine caused reflex bradycardia, reducing diastolic filling time and worsening subendocardial ischaemia in the hypertrophied ventricle

In severe aortic stenosis, the left ventricle is concentrically hypertrophied and heavily dependent on heart rate for cardiac output (CO = HR × SV). Phenylephrine's pure α1-agonism reliably causes baroreceptor-mediated reflex bradycardia. In a fixed-output state with a stiff, non-compliant ventricle, the resulting bradycardia dramatically reduces CO. Additionally, slower heart rate prolongs systole proportionally more than diastole at lower rates, impairing subendocardial perfusion in a hypertrophied myocardium with elevated end-diastolic pressure. Ephedrine or metaraminol (which preserve or increase HR) are preferred vasopressors in this context.

Question 18: Which statement about the use of PEEP during one-lung ventilation is TRUE?

PEEP to the dependent lung is contraindicated when PVR is elevated
PEEP on the ventilated lung reduces shunt by recruiting collapsed alveoli (Correct answer)
PEEP uniformly improves oxygenation in all OLV patients
PEEP should never be applied to avoid worsening HPV

Correct answer: PEEP on the ventilated lung reduces shunt by recruiting collapsed alveoli

Judicious PEEP (5 cmH2O) to the ventilated dependent lung recruits atelectatic alveoli and improves V/Q matching, though excessive PEEP can increase PVR and worsen hypoxemia.

Question 19: A 58-year-old patient undergoes ultrasound-guided erector spinae plane (ESP) block at the T5 level for thoracic surgery analgesia. Post-procedure, the patient develops unexpected ipsilateral lower limb weakness. Which anatomical mechanism best explains this complication?

Contralateral sympathetic block causing vasodilation and relative hypoperfusion of the motor cortex
Direct spread of local anaesthetic to the ipsilateral lumbar paravertebral space via the erector spinae fascial plane (Correct answer)
Epidural spread through the intervertebral foramina at the thoracolumbar junction
Intravascular injection into a radicular artery supplying the thoracic spinal cord

Correct answer: Direct spread of local anaesthetic to the ipsilateral lumbar paravertebral space via the erector spinae fascial plane

The ESP block deposits local anaesthetic deep to the erector spinae muscle and superficial to the transverse processes. The fascial plane is continuous craniocaudally, and large-volume injections can track inferiorly to the lumbar paravertebral space, potentially blocking lumbar nerve roots and causing lower limb motor weakness. This caudal spread has been documented in cadaveric and clinical studies and is the most plausible anatomical explanation for ipsilateral limb weakness remote from the injection site.

Question 20: Which test best reflects the extrinsic coagulation pathway?

Bleeding time
Thrombin time (TT)
Prothrombin time (PT) (Correct answer)
Activated partial thromboplastin time (aPTT)

Correct answer: Prothrombin time (PT)

Prothrombin time (PT) measures the extrinsic pathway (tissue factor/Factor VII) and common pathway.

Question 21: A type CF (cardiac-float) applied part is required for an intracardiac catheter connected to an ECG monitor during a procedure under general anaesthesia. The maximum permissible leakage current for a type CF applied part under single-fault conditions is:

500 µA
5 mA
50 µA (Correct answer)
10 µA

Correct answer: 50 µA

IEC 60601-1 classifies applied parts by their proximity to the heart and their leakage current tolerances. Type B (body) and type BF (body-float) parts have normal-condition limits of 100 µA and 10 µA respectively, rising under single-fault conditions to 500 µA and 500 µA. Type CF (cardiac-float) parts — designed for direct cardiac contact — have the most stringent limits: 10 µA under normal conditions and 50 µA under single-fault conditions. The lower threshold reflects the dramatically reduced threshold for ventricular fibrillation when current is delivered directly to the myocardium (approximately 50–100 µA), bypassing the impedance protection of skin and chest wall.

Question 22: A patient rescued from a house fire is brought to the emergency department. They are tachypneic and confused. A standard pulse oximeter shows a saturation (SpO2) of 98%, but an arterial blood gas analysis reveals a fractional oxyhemoglobin (SaO2) of 80% and a PaO2 of 95 mmHg. What is the most likely explanation for this discrepancy?

The presence of carboxyhemoglobin. (Correct answer)
Interference from intravenous methylene blue dye.
The presence of methemoglobinemia.
Severe peripheral vasoconstriction.

Correct answer: The presence of carboxyhemoglobin.

Standard two-wavelength pulse oximeters cannot differentiate between oxyhemoglobin and carboxyhemoglobin (COHb). COHb absorbs light at the 660 nm (red) wavelength similarly to oxyhemoglobin. The oximeter therefore 'sees' the COHb as if it were oxygenated, leading to a falsely high SpO2 reading. In smoke inhalation victims, significant CO poisoning is common. Methemoglobinemia would typically cause the SpO2 to trend towards 85%, regardless of the true SaO2. Severe vasoconstriction would lead to a weak or absent signal, not a specific, falsely high reading.

Question 23: Which uteroplacental characteristic is MOST relevant when selecting opioids for cesarean section spinal anesthesia?

pH partitioning causes opioid trapping in fetal circulation (Correct answer)
Molecular weight determines placental transfer
Protein binding prevents all placental transfer
Lipid solubility determines speed of placental transfer

Correct answer: pH partitioning causes opioid trapping in fetal circulation

Ion trapping occurs when fetal acidosis converts lipid-soluble opioids to ionized forms that cannot cross back, accumulating in fetal circulation.

Question 24: The critical temperature of nitrous oxide is 36.5°C. What does this mean for a full cylinder at room temperature?

The gas is at risk of combustion above 36.5°C
The cylinder pressure equals atmospheric pressure
The cylinder contains only gas at high pressure
The contents are in equilibrium between liquid and vapor phases (Correct answer)

Correct answer: The contents are in equilibrium between liquid and vapor phases

Below its critical temperature, N₂O exists as a liquid-vapor mixture; the cylinder pressure (approximately 50 bar) reflects the saturated vapor pressure, not the amount remaining.

Question 25: Which maternal condition is an absolute contraindication to neuraxial anesthesia for labor and delivery?

Platelet count of 90,000/μL
Gestational hypertension without coagulopathy
Patient refusal (Correct answer)
Previous back surgery

Correct answer: Patient refusal

Patient refusal is an absolute contraindication to any anesthetic procedure; all other listed conditions represent relative contraindications requiring individualized risk assessment.

Question 26: A neonate born at 28 weeks gestation undergoes emergent laparotomy for necrotizing enterocolitis at 3 weeks of postnatal age. Post-operatively, what is the minimum postconceptional age at which this infant can safely be managed without mandatory apnoea monitoring?

52 weeks postconceptional age (Correct answer)
44 weeks postconceptional age
60 weeks postconceptional age
No specific threshold exists; monitoring should continue until 6 months corrected age

Correct answer: 52 weeks postconceptional age

Former premature infants are at risk for postoperative apnoea due to immature respiratory control. The widely accepted threshold is 60 weeks postconceptional age, but because this infant was born at 28 weeks and is now 31 weeks postconceptional age, the relevant clinical guidance (supported by Cote et al. meta-analysis) recommends mandatory inpatient apnoea monitoring until at least 60 weeks postconceptional age. However, the threshold most supported in EDAIC-level literature for when apnoea risk becomes acceptably low is 60 weeks. 52 weeks is actually the threshold often cited for former term or near-term infants without comorbidities. Given extreme prematurity (28 weeks) and major abdominal surgery with anaemia risk, 60 weeks is the safest and most evidence-based answer cited in European anaesthesia guidelines.

Question 27: During thoracic surgery in the lateral decubitus position, the dependent lung has INCREASED perfusion because of:

Increased HPV in the non-dependent lung
Gravity-dependent redistribution of pulmonary blood flow (Correct answer)
Active bronchodilation of dependent airways
Reduced FRC causing reflex vasoconstriction in the non-dependent lung

Correct answer: Gravity-dependent redistribution of pulmonary blood flow

Gravity directs more blood flow to the dependent (down) lung in the lateral position, creating the basis for matched ventilation and perfusion during two-lung ventilation.

Question 28: The Pin Index Safety System (PISS) on gas cylinders is designed to:

Regulate pressure from the cylinder
Indicate the remaining volume of gas
Prevent backflow of gases into the cylinder
Prevent accidental connection of wrong gas cylinders to yokes (Correct answer)

Correct answer: Prevent accidental connection of wrong gas cylinders to yokes

PISS uses unique pin configurations for each gas to prevent incorrect cylinders from being mounted on the wrong yoke connection.

Question 29: A rotameter (Thorpe tube) in an anesthesia machine is calibrated for a specific gas because flow readings depend on:

Cylinder pressure of the gas
Gas temperature and pressure only
Gas density and viscosity (Correct answer)
Color-coding of the flowmeter tube

Correct answer: Gas density and viscosity

Rotameter readings depend on the physical properties (density and viscosity) of the gas, so each flowmeter tube is gas-specific and cannot be interchanged.

Question 30: A 72-year-old patient on rivaroxaban 20 mg once daily for non-valvular atrial fibrillation presents 4 hours after their last dose with a Glasgow Coma Scale of 8 and CT-confirmed large intracranial haematoma. Anti-Xa level is 195 ng/mL. Which andexanet alfa dosing regimen is correct?

Andexanet alfa is not licensed for rivaroxaban reversal; use 4-factor PCC instead
Low-dose: 400 mg IV bolus followed by 4 mg/min infusion for 120 minutes
High-dose: 800 mg IV bolus followed by 8 mg/min infusion for 120 minutes (Correct answer)
Low-dose bolus of 400 mg IV only, without a maintenance infusion

Correct answer: High-dose: 800 mg IV bolus followed by 8 mg/min infusion for 120 minutes

Andexanet alfa dosing is stratified by agent, dose, and time since last administration. For rivaroxaban: low-dose protocol applies when the dose was ≤10 mg OR the last dose was ≥8 hours prior; high-dose protocol applies when the dose was >10 mg AND the last dose was <8 hours prior. This patient received 20 mg (>10 mg threshold) just 4 hours ago (<8 h threshold), mandating the high-dose regimen (800 mg bolus + 8 mg/min × 120 min). The anti-Xa level of 195 ng/mL confirms significant residual drug activity. Andexanet alfa is licensed for both apixaban and rivaroxaban reversal.

Question 31: Which inhalational anesthetic is MOST associated with fluoride-mediated nephrotoxicity, particularly after prolonged exposure or in patients with pre-existing renal disease?

Desflurane
Sevoflurane
Isoflurane
Methoxyflurane (Correct answer)

Correct answer: Methoxyflurane

Methoxyflurane undergoes extensive hepatic defluorination producing serum fluoride concentrations above the nephrotoxic threshold (>50 µmol/L), historically causing high-output renal failure; sevoflurane's defluorination is modest and renal impact minimal.

Question 32: James Reason's 'Swiss cheese model' of accident causation is widely applied in patient safety. What does it describe?

A grading system for anaesthetic adverse events based on severity
The tendency for Swiss healthcare institutions to have superior safety cultures
Multiple defensive system layers each containing latent failures; harm occurs when failures in all layers align simultaneously (Correct answer)
A root cause analysis method in which errors are attributed to individual negligence

Correct answer: Multiple defensive system layers each containing latent failures; harm occurs when failures in all layers align simultaneously

In Reason's model, healthcare systems have multiple defensive barriers (like slices of cheese), each with latent holes (system weaknesses, not just individual errors). A critical incident occurs when holes in successive layers momentarily align, allowing a hazard to pass through all defences and cause harm. This model shifted safety thinking from 'blame the individual' to 'fix the system'.

Question 33: A 45-year-old presents with lancinating pain along the T5 dermatome following herpes zoster infection 6 months ago. What is the most accurate diagnosis?

Post-herpetic neuralgia (PHN) (Correct answer)
Intercostal neuralgia
Acute herpetic neuralgia
Complex regional pain syndrome type II

Correct answer: Post-herpetic neuralgia (PHN)

Post-herpetic neuralgia is defined as pain persisting in the distribution of herpes zoster beyond 90 days after acute infection onset, characterized by lancinating, burning, or allodynic pain.

Question 34: During laparoscopic right hemicolectomy for a midgut carcinoid tumour (confirmed 5-HIAA elevation preoperatively), manipulation of the mesentery triggers a carcinoid crisis: BP 52/30 mmHg, SpO₂ 84% with severe bronchospasm, widespread cutaneous flushing, and HR 48 bpm. IV fluid bolus (1 litre) produces no haemodynamic response. Which is the MOST appropriate immediate pharmacological intervention?

IV promethazine 25 mg and IV ranitidine 50 mg to block histamine-mediated H1 and H2 receptor activation
IV hydrocortisone 200 mg as anaphylaxis requires steroid therapy alongside vasopressor support
IV octreotide 500 micrograms bolus, repeated if necessary, followed by continuous infusion at 50–200 micrograms/hour (Correct answer)
IV epinephrine 100 micrograms bolus for combined vasopressor and bronchodilator effect in the setting of anaphylaxis-like presentation

Correct answer: IV octreotide 500 micrograms bolus, repeated if necessary, followed by continuous infusion at 50–200 micrograms/hour

Carcinoid crisis is a life-threatening release of tumour mediators (serotonin, bradykinin, histamine, tachykinins) precipitated by tumour handling. The hallmark treatment is IV octreotide — a somatostatin analogue that suppresses mediator release from enterochromaffin cells and can rapidly reverse all manifestations including bronchospasm, hypotension, and flushing. Critically, epinephrine is CONTRAINDICATED in carcinoid crisis: catecholamines stimulate further tumour mediator release (particularly bradykinin), potentially worsening the crisis catastrophically. This is a classic trap — the presentation mimics anaphylaxis but the treatment is opposite in one key aspect. Antihistamines and steroids are adjuncts at best and dangerously inadequate as primary therapy. The bradycardia in this case likely reflects a vasodepressor bradykinin effect rather than anaphylaxis-type mediator pattern. Octreotide should be available in theatre for all carcinoid resections.

Question 35: A 4-week-old ex-premature infant, born at 32 weeks gestation and now 36 weeks post-conceptional age, is scheduled for an inguinal hernia repair under general anesthesia. Which of the following represents the most significant postoperative risk for this specific patient?

Delayed emergence from anesthesia
Postoperative apnea (Correct answer)
Hypoglycemia
Hypothermia

Correct answer: Postoperative apnea

Ex-premature infants, particularly those less than 60 weeks post-conceptional age, have an immature central respiratory control system. This makes them highly susceptible to postoperative apnea and bradycardia, which may occur hours after an apparently uneventful recovery. This risk necessitates admission and cardiorespiratory monitoring for at least 12-24 hours post-surgery. While hypothermia and hypoglycemia are risks for all neonates, the risk of central apnea is the most pronounced and specific life-threatening concern for this demographic.

Question 36: For informed consent to anaesthesia to be legally and ethically valid, which of the following is the most complete description of what the patient must be told?

Only complications occurring in more than 1% of cases
Only the most serious (potentially fatal) complications
The statistical probability of each complication from published meta-analyses
The nature, purpose, material risks, benefits, and reasonable alternatives of the proposed anaesthetic (Correct answer)

Correct answer: The nature, purpose, material risks, benefits, and reasonable alternatives of the proposed anaesthetic

Valid informed consent requires disclosure of the nature of the procedure, its purpose, the material risks (those a reasonable patient would want to know, even if rare), the benefits, and available alternatives including no treatment. The 'material risk' standard (established in Montgomery v Lanarkshire and equivalent European case law) replaced the old 'reasonable doctor' standard — the patient's perspective now determines what must be disclosed, not just what clinicians deem important.

Question 37: A 72-year-old patient undergoes a 4-hour abdominal procedure maintained with a remifentanil infusion at 0.2 mcg/kg/min. At emergence, the anesthesiologist expects rapid offset of opioid effect. Which statement MOST accurately explains remifentanil's unique pharmacokinetic profile underlying this prediction?

Remifentanil's context-sensitive half-time remains short because its active metabolite (remifentanil acid) is rapidly cleared by renal excretion, preventing feedback inhibition of esterase activity
Remifentanil is metabolized by hepatic CYP3A4 with an extraction ratio exceeding 0.9, ensuring near-complete first-pass elimination and rapid plasma clearance
Remifentanil undergoes organ-independent ester hydrolysis by non-specific plasma and tissue esterases, resulting in a context-sensitive half-time of ~3–4 minutes that remains constant regardless of infusion duration (Correct answer)
Remifentanil's very high volume of distribution (~5 L/kg) limits tissue accumulation, preventing the context-sensitive half-time from rising beyond 30 minutes

Correct answer: Remifentanil undergoes organ-independent ester hydrolysis by non-specific plasma and tissue esterases, resulting in a context-sensitive half-time of ~3–4 minutes that remains constant regardless of infusion duration

Remifentanil is uniquely metabolized by ubiquitous non-specific esterases in blood and tissues (not plasma cholinesterase), yielding an extraordinarily high clearance (~3 L/min) that is independent of hepatic blood flow, renal function, or enzyme capacity. This is why its context-sensitive half-time is invariably ~3–4 minutes whether the infusion runs for 30 minutes or 8 hours — no peripheral accumulation occurs. Option B is incorrect: remifentanil is not a CYP3A4 substrate. Option C is incorrect: remifentanil has a small Vd (~0.35 L/kg). Option D is incorrect: remifentanil acid is pharmacologically inactive and does not regulate esterase kinetics.

Question 38: A 45-year-old woman with end-stage renal disease on haemodialysis requires general anaesthesia for a parathyroidectomy. Her pre-operative potassium is 6.1 mEq/L, ECG shows peaked T-waves, and her last dialysis was 48 hours ago. She has no IV access suitable for rapid volume replacement. Which induction agent combination is MOST appropriate?

Propofol 2 mg/kg + succinylcholine 1.5 mg/kg for rapid sequence induction
Ketamine 1.5 mg/kg + rocuronium 1.2 mg/kg with sugammadex immediately available (Correct answer)
Etomidate 0.3 mg/kg + succinylcholine 1.5 mg/kg for haemodynamic stability
Propofol 2 mg/kg + rocuronium 0.6 mg/kg with sugammadex immediately available

Correct answer: Ketamine 1.5 mg/kg + rocuronium 1.2 mg/kg with sugammadex immediately available

Succinylcholine is absolutely contraindicated with pre-existing hyperkalaemia (K+ ≥5.5 mEq/L) as it causes a predictable rise of 0.5–1.0 mEq/L via depolarisation-induced potassium efflux, risking ventricular fibrillation. Rocuronium 1.2 mg/kg provides RSI-equivalent intubating conditions in 60 seconds (equivalent to succinylcholine). Ketamine preserves sympathetic tone and haemodynamic stability, important in patients who may be intravascularly depleted from dialysis. Sugammadex must be available for reversal if needed. Propofol can cause significant vasodilation and hypotension in ESRD patients. Etomidate + succinylcholine is contraindicated due to the hyperkalaemia. Propofol + low-dose rocuronium (0.6 mg/kg) does not provide RSI conditions reliably.

Question 39: During one-lung ventilation (OLV) for a right pneumonectomy, the patient develops severe hypoxaemia (SpO₂ 78%) despite 100% FiO₂ and PEEP 5 cmH₂O to the dependent lung. Which intervention is MOST likely to improve oxygenation without compromising the surgical field?

Clamp the pulmonary artery on the operative side before re-expanding the lung
Switch to high-frequency jet ventilation of the dependent lung
Apply continuous positive airway pressure (CPAP) of 2–5 cmH₂O to the non-dependent (operative) lung (Correct answer)
Increase tidal volume to 10 mL/kg IBW on the dependent lung

Correct answer: Apply continuous positive airway pressure (CPAP) of 2–5 cmH₂O to the non-dependent (operative) lung

Low-level CPAP (2–5 cmH₂O) applied to the non-dependent operative lung recruits alveoli and allows passive oxygenation across a partially distended lung without full re-expansion, substantially reducing shunt fraction while keeping the surgical field acceptable. Increasing tidal volume risks ventilator-induced lung injury in the dependent lung. HFJV to the dependent lung is not a standard first-line rescue. PA clamping is a surgical manoeuvre appropriate only at the moment of pneumonectomy, not as an anaesthetic intervention for hypoxaemia.

Question 40: Which of the following most accurately explains why milrinone produces a greater increase in heart rate than dobutamine at equi-inotropic doses in patients with decompensated heart failure?

Dobutamine's simultaneous β2-mediated vasodilation triggers greater reflex sympathetic activation that opposes its chronotropic effect at the SA node
Milrinone directly activates sinoatrial node phosphodiesterase-3 isoforms, producing more profound chronotropy than the partial β1-agonism of dobutamine
Milrinone lacks β1-receptor agonism and therefore does not activate baroreceptor-mediated reflex bradycardia to counteract its tachycardic effect from peripheral vasodilation (Correct answer)
Milrinone's longer half-life causes sustained cAMP accumulation in nodal tissue, producing more persistent rate increases than the rapidly desensitizing β-receptor activation from dobutamine

Correct answer: Milrinone lacks β1-receptor agonism and therefore does not activate baroreceptor-mediated reflex bradycardia to counteract its tachycardic effect from peripheral vasodilation

Both milrinone and dobutamine increase heart rate through elevated intracellular cAMP. However, dobutamine directly stimulates β1-receptors in the SA node for its chronotropic effect but simultaneously activates β1-receptors in the myocardium improving contractility and cardiac output, which partially restores arterial pressure—thus triggering baroreceptor-mediated reflex parasympathetic activity (vagal tone increase) that opposes tachycardia. Milrinone, acting downstream of receptors via PDE-3 inhibition, bypasses receptor-level regulation and causes peripheral vasodilation that reduces afterload and mean arterial pressure, eliciting reflex sympathetic activation (increased HR) without the receptor-level counterbalancing. The net effect is greater tachycardia with milrinone relative to equivalent inotropic doses of dobutamine, particularly in patients with impaired baroreflex sensitivity.

Question 41: A patient develops tachyphylaxis to intravenous nitroglycerin after 24 hours of infusion for refractory vasospasm. The mechanism is MOST accurately described as:

Receptor downregulation at vascular smooth muscle guanylyl cyclase receptors
Increased hepatic first-pass metabolism through induction of nitrate reductase enzymes
Depletion of intracellular sulfhydryl (thiol) groups required for biotransformation of nitroglycerin to nitric oxide (Correct answer)
Competitive antagonism by endogenous vasoconstrictors upregulated in response to vasodilation

Correct answer: Depletion of intracellular sulfhydryl (thiol) groups required for biotransformation of nitroglycerin to nitric oxide

Nitroglycerin is a prodrug that requires biotransformation to nitric oxide (NO). This conversion depends on mitochondrial aldehyde dehydrogenase (ALDH2) and is critically dependent on intracellular sulfhydryl (thiol) groups as co-factors. Continuous nitroglycerin infusion depletes these thiol groups, impairing NO generation despite adequate drug concentrations. This is a well-characterized pharmacokinetic/pharmacodynamic tolerance mechanism specific to organic nitrates. Administration of N-acetylcysteine (a thiol donor) can partially restore nitroglycerin responsiveness. This differs from tolerance to other vasodilators which may involve receptor-mediated mechanisms.

Question 42: Which of the following best describes the effect of milrinone on cardiac physiology?

Pure chronotropic effect with no inotropy
Positive inotropy with vasoconstriction
Positive inotropy and vasodilation via PDE3 inhibition (Correct answer)
Negative inotropy with vasodilation

Correct answer: Positive inotropy and vasodilation via PDE3 inhibition

Milrinone inhibits phosphodiesterase III, increasing cAMP, causing positive inotropy in the heart and vasodilation in peripheral vessels (inodilator).

Question 43: A patient with severe hepatic cirrhosis (Child-Pugh C) requires analgesia. Compared to a healthy subject, which pharmacokinetic change is MOST likely to affect the free (unbound) plasma concentration of a highly protein-bound opioid such as fentanyl?

Reduced first-pass metabolism is the dominant change because fentanyl has a high extraction ratio
Decreased renal clearance of the glucuronide metabolite accumulates active drug
Reduced albumin synthesis increases the free fraction, raising pharmacodynamic effect despite a similar total plasma concentration (Correct answer)
Decreased hepatic blood flow prolongs the elimination half-life without altering the free fraction

Correct answer: Reduced albumin synthesis increases the free fraction, raising pharmacodynamic effect despite a similar total plasma concentration

In Child-Pugh C cirrhosis, albumin synthesis falls markedly, reducing protein binding for acidic and neutral drugs including fentanyl (normally ~80% protein-bound). A lower bound fraction means a higher free fraction at any given total plasma concentration, amplifying pharmacodynamic effect even when total drug levels appear 'normal'. Hepatic blood flow and extraction ratio changes are secondary considerations; fentanyl's glucuronide metabolites are inactive.

Question 44: A patient is being ventilated via a Mapleson A (Magill) circuit during spontaneous ventilation. The fresh gas flow required to prevent rebreathing is approximately equal to the patient's alveolar minute ventilation. If the same circuit is used for controlled mechanical ventilation, how does the FGF requirement change?

It remains the same, as FGF requirement is independent of ventilation mode
It decreases to approximately 70% of minute ventilation due to reduced dead space
It increases to approximately 2–3 times the minute ventilation (Correct answer)
It decreases to 50% of minute ventilation because the reservoir bag acts as a buffer

Correct answer: It increases to approximately 2–3 times the minute ventilation

The Mapleson A circuit is highly efficient for spontaneous ventilation because expiratory valve placement allows exhaled alveolar gas to be vented early in expiration before the fresh gas washes it back. During controlled ventilation, however, the expiratory valve must remain closed during inspiration, trapping exhaled gas in the circuit and causing significant rebreathing. To prevent this, an FGF of approximately 2–3 times the minute ventilation (typically >20 L/min) is required — making the Mapleson A the worst circuit for controlled ventilation. This is the inverse of the Mapleson D/E/F (Bain) circuits, which are efficient for controlled but inefficient for spontaneous ventilation.

Question 45: Thermodilution cardiac output measurements are performed via a pulmonary artery catheter in a patient with severe tricuspid regurgitation (regurgitant fraction ~55%). Compared with the true forward cardiac output, thermodilution will most likely:

Be unaffected, as the thermistor is sited distal to the tricuspid valve in the pulmonary artery
Overestimate cardiac output because cold injectate is cleared more rapidly by the regurgitant jet
Underestimate cardiac output because recirculating cold injectate prolongs the temperature–time curve (Correct answer)
Overestimate cardiac output because the larger right ventricle reduces mixing of the thermal indicator

Correct answer: Underestimate cardiac output because recirculating cold injectate prolongs the temperature–time curve

The Stewart-Hamilton equation calculates cardiac output as inversely proportional to the area under the blood-temperature–time curve (∫ΔTB dt). With severe tricuspid regurgitation, cold injectate regurgitates back into the right atrium and recirculates, prolonging the thermal deflection at the pulmonary artery thermistor. This enlarges the integral, and because CO is inversely related to this area, the calculated CO is artifactually low — an underestimation of true forward output. The degree of error correlates with regurgitant fraction severity. Tricuspid regurgitation, intracardiac shunts, and respiratory variation are all recognised sources of thermodilution inaccuracy.

Question 46: Which safety feature of modern anesthesia ventilators is designed to limit airway pressure and prevent barotrauma?

Adjustable pressure-limiting (APL) valve set to a defined peak pressure (Correct answer)
Low-pressure alarm on the pipeline inlet
Oxygen flush valve bypass
Spirometer volume alarm

Correct answer: Adjustable pressure-limiting (APL) valve set to a defined peak pressure

The APL (pop-off) valve can be set to a maximum pressure limit so that excess pressure is vented, protecting the patient's lungs from barotrauma.

Question 47: A 58-year-old patient undergoing right pneumonectomy develops sudden cardiovascular collapse 90 minutes post-extubation. Transthoracic echocardiography reveals a hyperdynamic left ventricle with near-obliteration of the left ventricular cavity in systole. The MOST likely underlying mechanism is:

Massive pulmonary embolism to the remaining left lung
Dynamic left ventricular outflow tract obstruction due to intravascular volume depletion and catecholamine surge (Correct answer)
Acute right ventricular failure from pulmonary hypertension
Tension pneumothorax on the contralateral side

Correct answer: Dynamic left ventricular outflow tract obstruction due to intravascular volume depletion and catecholamine surge

Post-pneumonectomy patients are at risk for dynamic LVOTO due to the combination of a hyperdynamic state (catecholamines, pain, fever) and relative hypovolemia. This results in systolic anterior motion of the mitral valve and functional outflow obstruction, presenting as obstructive shock with a hyperdynamic, underfilled ventricle on echo. Treatment requires volume resuscitation, beta-blockade, and avoidance of vasodilators. Acute RV failure would show a dilated, hypokinetic RV, not a hyperdynamic LV.

Question 48: Which of the following is a direct effect of acute hyperkalemia on cardiac electrophysiology?

Shortened PR interval
Prolonged phase 0 upstroke velocity
Decreased resting membrane potential (less negative) causing partial depolarization (Correct answer)
Increased automaticity of Purkinje fibers

Correct answer: Decreased resting membrane potential (less negative) causing partial depolarization

Hyperkalemia reduces the electrochemical gradient for potassium, making the resting membrane potential less negative, partially inactivating fast sodium channels and slowing conduction.

Question 49: A primiparous patient at 39 weeks receives a combined spinal-epidural (CSE) for labour analgesia. Thirty minutes after intrathecal sufentanil 10 mcg + bupivacaine 2.5 mg, she develops severe fetal bradycardia to 60 bpm. Her blood pressure is 118/74 mmHg, SpO2 is 99%, and she has no uterine hyperstimulation on tocometry. Which mechanism BEST explains this complication?

Uteroplacental vasoconstriction from systemic opioid absorption
Direct fetal myocardial depression from placental opioid transfer
Uterine hypertonus secondary to rapid fall in circulating catecholamines (Correct answer)
Maternal hypotension causing uteroplacental insufficiency

Correct answer: Uterine hypertonus secondary to rapid fall in circulating catecholamines

Fetal bradycardia following CSE without maternal hypotension is a well-documented phenomenon, occurring in approximately 8–14% of cases. The most accepted mechanism is uterine hypertonus caused by a sudden decrease in circulating maternal epinephrine (which has tocolytic beta-2 effects) following rapid opioid-induced pain relief. With pain abolished, catecholamine levels fall precipitously, removing their tocolytic effect and allowing oxytocin-driven uterine tone to increase, reducing intervillous blood flow. Maternal hypotension (option C) is excluded by the normal blood pressure. Systemic opioid absorption (option A) is minor and not the dominant pathway. Direct fetal myocardial depression (option D) does not occur at these intrathecal doses with intact placental metabolism.

Question 50: In a child with tetralogy of Fallot presenting for non-cardiac surgery, which induction agent is MOST appropriate?

Etomidate
Thiopental
Ketamine (Correct answer)
Propofol

Correct answer: Ketamine

Ketamine maintains or increases systemic vascular resistance, which is beneficial in right-to-left shunting lesions like tetralogy of Fallot by reducing the degree of shunting.

Question 51: A 68-year-old patient with Child-Pugh Class C liver cirrhosis is anesthetized for a TIPS procedure. Fentanyl, a highly protein-bound opioid with a high hepatic extraction ratio, is administered. Which pharmacokinetic changes are most significant in this patient compared to a healthy individual?

Decreased drug potency at the mu-opioid receptor.
Increased free drug fraction and decreased hepatic clearance. (Correct answer)
Increased plasma protein binding and a higher first-pass metabolism.
Decreased volume of distribution and increased hepatic clearance.

Correct answer: Increased free drug fraction and decreased hepatic clearance.

In severe liver disease, synthesis of plasma proteins like albumin is reduced, leading to less protein binding and a higher fraction of unbound, pharmacologically active drug. Additionally, both liver blood flow and enzymatic function are impaired, which significantly decreases the clearance of drugs with a high hepatic extraction ratio, like fentanyl. This combination leads to a more pronounced and prolonged effect.

Question 52: During orthotopic liver transplantation, ROTEM analysis at the start of reperfusion reveals: EXTEM CT 840s (ref <80s), INTEM CT 620s (ref <240s), but HEPTEM CT 74s (ref <240s). EXTEM MCF and FIBTEM MCF are both within normal limits. What is the most appropriate immediate intervention?

Fresh frozen plasma 15 mL/kg to correct clotting factor deficiency
Tranexamic acid 1 g to treat hyperfibrinolysis from reperfusion
Protamine sulfate 25–50 mg IV to reverse heparin effect from the donor liver flush (Correct answer)
Fibrinogen concentrate 2 g to improve clot firmness

Correct answer: Protamine sulfate 25–50 mg IV to reverse heparin effect from the donor liver flush

HEPTEM contains heparinase, which neutralises heparin in the sample. When HEPTEM CT normalises while EXTEM and INTEM CTs are markedly prolonged — with preserved MCF values — the pattern is pathognomonic for heparin effect rather than factor deficiency or fibrinolysis. This occurs because donor livers are flushed with heparin-containing preservation solution (e.g., University of Wisconsin solution) that releases into the circulation upon reperfusion. Small doses of protamine (25–50 mg) reverse this rapidly. FFP would not address a heparin effect, fibrinogen concentrate is irrelevant when MCF is normal, and TXA treats fibrinolysis (which would show an abnormal APTEM pattern).

Question 53: A 29-year-old male presents with progressive ascending weakness, areflexia, and autonomic instability 3 weeks after a gastrointestinal illness. He develops acute respiratory failure requiring intubation. His CSF shows albumino-cytological dissociation. Which of the following statements about ICU management of Guillain-Barré syndrome is MOST accurate?

Corticosteroids are a useful adjunct to IVIg and should be routinely added
Plasma exchange and IVIg are equally effective and should not be combined as combination therapy is no more beneficial than either alone (Correct answer)
Early tracheostomy within 48 hours of intubation is mandatory to prevent ventilator-associated pneumonia
IVIg is preferred over plasma exchange because of superior long-term neurological outcomes at 6 months

Correct answer: Plasma exchange and IVIg are equally effective and should not be combined as combination therapy is no more beneficial than either alone

The Dutch GBS Study Group and subsequent Cochrane reviews confirm that plasma exchange (PE) and IVIg are equally effective in GBS. Crucially, combining both treatments offers no additional benefit over either alone — a common misconception. IVIg is preferred for practical reasons (easier to administer, lower risk profile) but not due to superior neurological outcomes at 6 months, which are equivalent. Corticosteroids (including IV methylprednisolone) have been shown in RCTs to be ineffective and are not recommended. Early tracheostomy timing depends on clinical trajectory (NIV trials, bulbar function, expected duration >2 weeks), not a blanket 48-hour rule.

Question 54: During a continuous erector spinae plane (ESP) block for thoracic surgery analgesia, you notice the patient develops a T4–T8 dermatomal sensory block but reports pain in the ipsilateral shoulder and anterior chest wall. Which mechanism best explains this analgesic gap?

Failure of local anaesthetic to reach the dorsal rami at the target levels
Sparing of the lateral cutaneous branches of intercostal nerves T2–T4 (Correct answer)
Inadequate spread to rami communicantes supplying visceral afferents
Incomplete block of the ipsilateral phrenic nerve (C3–C5)

Correct answer: Sparing of the lateral cutaneous branches of intercostal nerves T2–T4

The ESP block acts primarily on dorsal and ventral rami via paravertebral spread. However, the lateral cutaneous branches of the upper intercostal nerves (T2–T4) pierce the serratus anterior and supply the anterior and lateral chest wall including pectoral and axillary regions. These branches can be spared if spread is insufficient anteriorly. Phrenic nerve involvement does not explain anterior chest wall pain, and rami communicantes carry visceral afferents, not somatic shoulder/chest pain. The dorsal rami supply the posterior thorax only.

Question 55: You are managing a patient on veno-venous ECMO (VV-ECMO) for severe ARDS who requires airway exchange due to a cuffed tube with a ruptured cuff. Current ventilator settings: Vt 3 ml/kg IBW, PEEP 14, FiO2 0.8. ECMO flow 4.5 L/min, SpO2 88% (acceptable per team). What is the MOST important airway exchange consideration unique to this patient?

Use an airway exchange catheter (AEC) with continuous oxygen insufflation at 15 L/min throughout the exchange
Avoid paralysis during exchange to preserve spontaneous respiratory effort and maintain auto-PEEP
Minimise interruption to PEEP during the exchange to prevent diastolic dysfunction from hypoxia-induced pulmonary vasoconstriction
Increase ECMO sweep gas FiO2 to 1.0 and flow to maximum before the exchange to maximise oxygen reserve (Correct answer)

Correct answer: Increase ECMO sweep gas FiO2 to 1.0 and flow to maximum before the exchange to maximise oxygen reserve

In VV-ECMO for severe ARDS, the ECMO circuit is providing a substantial portion of oxygenation and CO2 removal. Unlike the native lung, the ECMO circuit's oxygen delivery can be transiently maximised by increasing sweep gas FiO2 to 1.0 and pump flow to maximum — this creates the greatest oxygen reserve during the brief apnoeic period of tube exchange and is the intervention unique to ECMO management. Using an AEC with insufflation is correct technique but risks barotrauma in stiff ARDS lungs with high PEEP, particularly with flow rates of 15 L/min which can generate significant pressure against a partially obstructed circuit. Maintaining PEEP is important but secondary to ensuring maximum systemic oxygenation via ECMO. Avoiding paralysis is incorrect — complete relaxation ensures the exchange is smooth and minimises coughing, which could dislodge the AEC or cause haemodynamic compromise.

Question 56: In the pressure-volume loop of the left ventricle, the width of the loop represents:

Cardiac output
Contractility
Stroke volume (Correct answer)
Heart rate

Correct answer: Stroke volume

The horizontal width of the LV pressure-volume loop represents stroke volume (the difference between end-diastolic and end-systolic volumes).

Question 57: Anemia in chronic renal failure is primarily caused by:

Folate deficiency from dialysis
Iron deficiency from dietary restriction
Bone marrow suppression from uremic toxins alone
Decreased erythropoietin production by damaged kidneys (Correct answer)

Correct answer: Decreased erythropoietin production by damaged kidneys

The kidneys produce erythropoietin in response to hypoxia; in CKD, reduced erythropoietin synthesis leads to normochromic normocytic anemia.

Question 58: A patient with a known mediastinal mass causing 60% tracheal compression at the carina is scheduled for tissue biopsy under general anesthesia. After induction and tracheal intubation, complete airway obstruction occurs despite the ETT tip being above the carina. The MOST effective immediate maneuver is:

Advance the ETT past the carina into the right main bronchus (Correct answer)
Change patient position to prone and attempt manual chest compressions
Withdraw the ETT to a more proximal tracheal position and apply positive end-expiratory pressure
Change patient position to lateral decubitus and apply continuous positive airway pressure

Correct answer: Advance the ETT past the carina into the right main bronchus

Mediastinal masses can cause dynamic airway compression at or below the carina. When extrinsic compression occludes the distal trachea or mainstem bronchi after induction (due to loss of muscle tone and negative intrathoracic pressure), advancing the ETT past the obstruction into the right or left main bronchus can re-establish a patent airway lumen distal to the mass. Changing to lateral decubitus may help in some cases by shifting the mass, but is a slower maneuver. Prone positioning has no established benefit for acute tracheal obstruction. Withdrawing the ETT would worsen obstruction if the carina is the level of compression.

Question 59: The velocity of conduction is SLOWEST through which cardiac structure?

Ventricular myocardium
Bundle of His
Purkinje fibers
AV node (Correct answer)

Correct answer: AV node

The AV node has the slowest conduction velocity (~0.05 m/s), creating the essential delay between atrial and ventricular contraction.

Question 60: In the context of dilutional coagulopathy during massive transfusion, which statement correctly describes the relationship between prothrombin time (PT) prolongation and actual surgical bleeding risk?

The PT measures only the extrinsic/common pathway under optimised in-vitro conditions at 37°C with excess tissue factor; it poorly reflects in-vivo thrombin generation capacity, and significant coagulopathy can exist with a PT <1.5× normal, while many patients with PT >1.5× normal do not bleed microvascularly (Correct answer)
The PT is rendered invalid during massive transfusion because citrate anticoagulant from packed red cells chelates calcium in recipient plasma, artificially prolonging clotting times ex-vivo
PT prolongation during massive transfusion invariably reflects factor VII deficiency, as factor VII has the shortest half-life; selective factor VII supplementation is therefore preferable to FFP
PT is a highly sensitive predictor of microvascular bleeding; a PT ratio >1.5× normal reliably indicates clinically significant coagulopathy requiring FFP in all surgical patients

Correct answer: The PT measures only the extrinsic/common pathway under optimised in-vitro conditions at 37°C with excess tissue factor; it poorly reflects in-vivo thrombin generation capacity, and significant coagulopathy can exist with a PT <1.5× normal, while many patients with PT >1.5× normal do not bleed microvascularly

The PT (and INR) is performed in plasma at 37°C with supraphysiological concentrations of tissue factor, calcium, and phospholipid added — conditions that maximise clotting efficiency far beyond what occurs in vivo. Studies consistently show poor correlation between PT <1.5× normal and actual microvascular bleeding, and many patients with modestly elevated PT do not bleed. Conversely, viscoelastic testing (ROTEM/TEG) is more predictive of surgical coagulopathy. The TRICC and other trials demonstrate that PT-guided transfusion triggers lead to over-transfusion of FFP. While factor VII has the shortest half-life (~4–6 hours), PT prolongation in dilutional coagulopathy reflects global factor dilution, not selective factor VII deficiency. Citrate in RBC units is rapidly metabolised by the liver and does not materially affect recipient PT.

Question 61: A 72-year-old patient on therapeutic enoxaparin (1 mg/kg twice daily) for deep vein thrombosis requires urgent hip fracture surgery. The last dose was administered 8 hours ago. According to ESRA (European Society of Regional Anaesthesia) guidelines, what is the minimum additional waiting period before performing a spinal anaesthetic?

36 more hours (total 44 hours from last therapeutic dose)
16 more hours (total 24 hours from last therapeutic dose) (Correct answer)
4 more hours (total 12 hours from last therapeutic dose)
No additional wait is required if anti-Xa level is <0.1 IU/mL

Correct answer: 16 more hours (total 24 hours from last therapeutic dose)

ESRA guidelines specify that for therapeutic (twice-daily) dose low-molecular-weight heparin (LMWH), a minimum interval of 24 hours from the last dose is required before neuraxial blockade. Since the last dose was 8 hours ago, an additional 16 hours must elapse. This is distinguished from prophylactic LMWH dosing (which requires only 12 hours). Anti-Xa level monitoring may be used as an adjunct but does not replace the mandatory time interval in ESRA's risk-stratified algorithm for therapeutic LMWH, and the threshold of <0.1 IU/mL alone is insufficient without the time criterion being met.

Question 62: A patient with hypertrophic obstructive cardiomyopathy (HOCM) develops hypotension intraoperatively. An anaesthetist administers phenylephrine, increases IV fluid rate, and decreases the volatile agent concentration. A colleague argues this will worsen the obstruction. Who is correct, and why?

The colleague is correct: phenylephrine increases LV afterload, causing reflex bradycardia and diastolic overfilling that worsens systolic anterior motion (SAM) of the mitral valve
The anaesthetist is partially correct: phenylephrine and fluid are appropriate but reducing volatile anaesthetic is harmful as volatile agents reduce contractility and therefore reduce obstruction
The anaesthetist is correct: all three interventions increase preload or afterload and reduce heart rate, each of which independently decreases dynamic LVOT obstruction in HOCM (Correct answer)
The colleague is partially correct: fluid loading is harmful in HOCM because increased preload dilates the LVOT and worsens SAM, while phenylephrine is beneficial

Correct answer: The anaesthetist is correct: all three interventions increase preload or afterload and reduce heart rate, each of which independently decreases dynamic LVOT obstruction in HOCM

Dynamic LVOT obstruction in HOCM is worsened by three factors: (1) reduced preload — smaller LV cavity brings septal and anterior mitral leaflet closer together; (2) reduced afterload — lower aortic pressure allows more complete and rapid ejection, increasing the Venturi effect drawing the mitral leaflet into the LVOT; (3) increased contractility or heart rate — augmented ejection velocity exacerbates obstruction. The anaesthetist's three interventions all counteract these: phenylephrine raises SVR (increases afterload), fluid increases preload (enlarges LV cavity), and reducing volatile agent decreases myocardial depression — wait, this is the subtlety: volatile agents REDUCE contractility, which REDUCES obstruction. Therefore reducing volatile agent concentration actually WORSENS obstruction by increasing contractility. However, the reduction was to treat hypotension — the net haemodynamic improvement from phenylephrine and fluids outweighs the contractility concern in this scenario, making all three interventions collectively correct in management despite the nuance. Option B correctly describes that each of the three mechanisms is being addressed in the right direction per HOCM physiology.

Question 63: During epidural top-up with 20 mL of 2% lidocaine with 1:200,000 epinephrine for urgent Caesarean section, the parturient abruptly loses consciousness with tonic-clonic movements and is pulseless. Resuscitation is commenced. Which statement regarding lipid emulsion therapy in this context is MOST accurate?

Lipid emulsion acts primarily by providing an alternative energy substrate for the ischaemic myocardium rather than by sequestering local anaesthetic
20% lipid emulsion should be administered as 1.5 mL/kg IV bolus immediately, followed by infusion, and Caesarean section should proceed if ROSC is not achieved within 5 minutes of ACLS (Correct answer)
Lipid emulsion is contraindicated in pregnancy as it crosses the placenta and causes foetal bradycardia
The initial bolus should be reduced to 0.5 mL/kg (ideal body weight) in the parturient to avoid pulmonary lipid microembolism

Correct answer: 20% lipid emulsion should be administered as 1.5 mL/kg IV bolus immediately, followed by infusion, and Caesarean section should proceed if ROSC is not achieved within 5 minutes of ACLS

ACLS guidelines for local anaesthetic systemic toxicity (LAST) recommend 20% intralipid 1.5 mL/kg bolus (not reduced in pregnancy) followed by 0.25 mL/kg/min infusion. The mechanism of lipid emulsion includes both lipid sink (sequestration) and direct metabolic effects on the myocardium — the 'lipid sink' hypothesis is now considered secondary to direct cardioprotective effects. Critically, in a pregnant patient with refractory cardiac arrest, perimortem Caesarean section (PMCS) should be initiated within 4-5 minutes of cardiac arrest (ideally delivery by 5 minutes) to relieve aortocaval compression and improve resuscitation success — this represents both maternal and foetal salvage. Lipid emulsion is not contraindicated in pregnancy.

Question 64: A pressure transducer for invasive blood pressure monitoring is calibrated at heart level. Raising the transducer 10 cm above heart level will:

Falsely lower the displayed pressure by ~7.5 mmHg (Correct answer)
Have no effect because the transducer is zeroed
Falsely elevate the displayed pressure by ~7.5 mmHg
Double the systolic reading

Correct answer: Falsely lower the displayed pressure by ~7.5 mmHg

Every 13.6 cm of height difference corresponds to ~10 mmHg; raising the transducer 10 cm reduces the hydrostatic column and causes a false low reading of ~7.5 mmHg.

Question 65: A 58-year-old patient on warfarin (INR 3.8) requires emergency reversal before urgent neurosurgery. You administer 4-factor PCC (50 IU/kg). Thirty minutes later the INR is still 2.1. Which statement best explains this residual coagulopathy and guides your next step?

The residual INR elevation is an artifact of heparin contamination in PCC vials; repeat the INR using a thrombin time to unmask true factor activity
PCC corrects factors II, VII, IX, X but not protein C/S; residual INR elevation reflects ongoing factor VII inhibition and a further PCC dose is contraindicated — give FFP instead
4-factor PCC does not correct factor VII adequately at standard dosing; recombinant factor VIIa (rFVIIa) 90 mcg/kg should be given as rescue therapy
Warfarin also inhibits vitamin K–dependent carboxylation of factors in the endoplasmic reticulum; until hepatic re-synthesis is complete the functional factor activity will lag behind the measured INR, and a single dose of IV vitamin K 10 mg is the appropriate adjunct (Correct answer)

Correct answer: Warfarin also inhibits vitamin K–dependent carboxylation of factors in the endoplasmic reticulum; until hepatic re-synthesis is complete the functional factor activity will lag behind the measured INR, and a single dose of IV vitamin K 10 mg is the appropriate adjunct

PCC rapidly replenishes the vitamin K–dependent clotting factors (II, VII, IX, X, protein C and S), but these are the carboxylated forms stored in the vial. Warfarin blocks hepatic γ-carboxylation, so newly synthesised factors remain non-functional until vitamin K is restored. IV vitamin K (5–10 mg) enables resumed carboxylation within 6–12 hours and is a mandatory adjunct to PCC for complete and durable reversal. A second PCC dose risks thromboembolism and is rarely indicated; rFVIIa is not first-line here; and heparin contamination is not a clinically meaningful source of INR elevation with modern PCCs.

Question 66: During a Valsalva maneuver performed for diagnostic purposes, a patient with hypertrophic obstructive cardiomyopathy (HOCM) exhibits paradoxical worsening of symptoms during Phase II (straining phase) and dramatic improvement during Phase IV (overshoot). Which hemodynamic sequence best explains this pattern?

Phase II causes coronary steal via Venturi effect at the LVOT, producing ischemia-related symptoms; Phase IV restores coronary perfusion pressure through the overshoot hypertension
Phase II activates the Bezold-Jarisch reflex through LV mechanoreceptors stimulated by obstruction, causing bradycardia; Phase IV deactivates this reflex restoring normal chronotropy
Phase II increases intrathoracic pressure compressing the aorta and increasing afterload, worsening LVOT obstruction; Phase IV normalizes intrathoracic pressure and afterload simultaneously
Phase II reduces venous return and LV cavity size, increasing dynamic LVOT obstruction; Phase IV overshoot increases LV preload via the reflex tachycardia and increased venous return, enlarging the LV cavity and reducing the dynamic gradient (Correct answer)

Correct answer: Phase II reduces venous return and LV cavity size, increasing dynamic LVOT obstruction; Phase IV overshoot increases LV preload via the reflex tachycardia and increased venous return, enlarging the LV cavity and reducing the dynamic gradient

In HOCM, the severity of dynamic LVOT obstruction is exquisitely sensitive to LV cavity size—smaller cavities worsen obstruction. During Valsalva Phase II (sustained straining), elevated intrathoracic pressure impedes venous return, reducing LV preload and end-diastolic volume. The smaller LV cavity causes the hypertrophied septum and anterior mitral leaflet (systolic anterior motion—SAM) to approximate more closely, dramatically worsening the dynamic gradient and murmur. During Phase IV overshoot, the release of straining triggers a surge in venous return augmented by reflex sympathetic tachycardia and increased cardiac output, rapidly filling the LV. This increased LV preload enlarges the cavity, physically separating the obstruction elements and reducing the gradient—explaining the dramatic symptom improvement. This is the physiological basis of the 'Valsalva test' being pathognomonic for HOCM.

Question 67: A patient with CKD stage 5 (GFR 9 mL/min, not yet on dialysis) undergoes elective inguinal hernia repair under general anaesthesia with rocuronium 0.6 mg/kg. At closure, TOF ratio is 0.3 and sugammadex 200 mg IV is administered, achieving TOF ratio >0.9 within 3 minutes. What is the MOST clinically significant pharmacokinetic concern in this specific patient?

The sugammadex–rocuronium complex is renally excreted; accumulation in severe CKD raises concern for delayed complex dissociation and recurarisation in the post-operative period (Correct answer)
Hyperkalaemia in CKD potentiates rocuronium binding to acetylcholine receptors, rendering sugammadex structurally unable to encapsulate the drug
Metabolic acidosis in CKD shifts the pH-dependent binding affinity of sugammadex away from rocuronium, requiring a repeat dose within 30 minutes
Reduced plasma protein binding of sugammadex in uraemia will increase free drug concentration and cause paradoxical neuromuscular blockade

Correct answer: The sugammadex–rocuronium complex is renally excreted; accumulation in severe CKD raises concern for delayed complex dissociation and recurarisation in the post-operative period

Sugammadex and the sugammadex–rocuronium complex are both primarily eliminated by renal excretion. In severe renal impairment (GFR <30 mL/min), the complex accumulates rather than being cleared. Although sugammadex–rocuronium binding is highly stable, theoretical dissociation of the complex in the context of prolonged plasma exposure raises concern for late recurarisation. Regulatory guidance (EMA/FDA) recommends avoiding sugammadex in GFR <30 mL/min for this reason. The reversal itself can still occur acutely, but the post-operative period carries real risk — patients should be monitored for respiratory adequacy well beyond the immediate recovery phase. Options A, C, and D describe pharmacologically implausible mechanisms.

Question 68: When using a double-lumen tube (DLT) for OLV, fibreoptic bronchoscopy confirms correct initial placement. After repositioning the patient from supine to lateral decubitus, SpO₂ drops and breath sounds are heard bilaterally but with wheeze. What is the MOST probable cause?

The DLT has migrated proximally, making the bronchial cuff sit above the carina and both lumens now ventilate both lungs (Correct answer)
The patient has developed bronchospasm in the dependent lung
The tracheal lumen cuff has herniated over the carina
The DLT has migrated distally, with the bronchial cuff now obstructing the right upper lobe bronchus

Correct answer: The DLT has migrated proximally, making the bronchial cuff sit above the carina and both lumens now ventilate both lungs

Repositioning from supine to lateral commonly causes proximal migration of a DLT (the tube effectively 'rides up' with gravity and neck/thorax movement). If the bronchial cuff retreats above the carina, both lumens open to both lungs — bilateral breath sounds return, but the loss of lung isolation leads to inadequate surgical conditions and the 'wheeze' may reflect carina stimulation or partial obstruction. Distal migration would cause right upper lobe obstruction (right DLT) or complete right lung exclusion (left DLT), not bilateral sounds. Cuff herniation over the carina causes complete airway obstruction, not bilateral ventilation. Bronchospasm is possible but does not explain bilateral sounds returning after previous successful isolation.

Question 69: A patient with severe hepatic cirrhosis (Child-Pugh C) receives a continuous infusion of midazolam. After 72 hours, the patient remains deeply sedated 18 hours after the infusion is stopped. Which pharmacokinetic mechanism BEST explains this prolonged effect beyond simple reduced hepatic clearance?

Accumulation of the active metabolite 1-hydroxymidazolam glucuronide due to impaired renal clearance secondary to hepatorenal syndrome (Correct answer)
Reduced plasma protein binding increasing free drug fraction, paradoxically slowing redistribution from the CNS
Upregulation of GABA-A receptors in cirrhotic patients creating pharmacodynamic sensitization
Induction of CYP3A4 by endogenous bile acids increasing toxic metabolite formation

Correct answer: Accumulation of the active metabolite 1-hydroxymidazolam glucuronide due to impaired renal clearance secondary to hepatorenal syndrome

In hepatic cirrhosis, particularly with concurrent renal dysfunction (hepatorenal syndrome), the active metabolite 1-hydroxymidazolam glucuronide accumulates. This metabolite is renally cleared and has significant GABA-A agonist activity. While reduced hepatic clearance of the parent drug is the primary mechanism, the prolonged sedation often seen clinically is disproportionate and attributable to this active metabolite accumulation — a phenomenon documented in ICU patients with multi-organ dysfunction.

Question 70: A paramagnetic O₂ analyser in the inspiratory limb of a circle system reads 32% during maintenance of anaesthesia with sevoflurane in an O₂/air mixture (set FiO₂ 0.40). The agent analyser simultaneously reads sevoflurane 2.1%. The MOST likely explanation for the discrepancy in the O₂ reading is:

Cross-sensitivity of the paramagnetic analyser to nitrous oxide contaminating the circuit
Preferential uptake of O₂ by the patient exceeding the O₂ delivery rate, creating a true hypoxic mixture
Paramagnetic interference from the diamagnetic properties of sevoflurane vapour at elevated concentrations (Correct answer)
A leak at the paramagnetic cell causing dilution with room air inside the analyser

Correct answer: Paramagnetic interference from the diamagnetic properties of sevoflurane vapour at elevated concentrations

Paramagnetic O₂ analysers measure oxygen by exploiting its unique paramagnetic susceptibility (O₂ is attracted into a magnetic field). However, most volatile anaesthetic agents — including sevoflurane, isoflurane, and desflurane — are diamagnetic (weakly repelled from a magnetic field) and at clinically significant concentrations can interfere with the paramagnetic cell, causing artificially low O₂ readings. At 2.1% sevoflurane, this interference is measurable and clinically relevant. This is a known limitation of paramagnetic analysers not fully compensated by older instruments. A 10-percentage-point drop for a set FiO₂ of 0.40 would be extreme for a simple cell leak (option A). Nitrous oxide (option B) is not in the circuit. Option D would require metabolic O₂ consumption to exceed delivery, which would show on other monitors first.

Question 71: A 58-year-old patient with a known anterior mediastinal mass is anaesthetised in the supine position. After induction and neuromuscular blockade, SpO2 drops to 82% and ventilation becomes impossible despite high airway pressures. Fibreoptic bronchoscopy reveals severe external compression of the distal trachea at the carina. Which intervention is most likely to restore ventilation?

Apply high-frequency jet ventilation via a rigid bronchoscope
Change to lateral or prone positioning immediately (Correct answer)
Increase tidal volume and respiratory rate to overcome obstruction
Advance the ETT beyond the carina into the right main bronchus

Correct answer: Change to lateral or prone positioning immediately

Anterior mediastinal masses can cause life-threatening tracheobronchial compression under general anaesthesia due to loss of spontaneous breathing and muscle tone. Positioning the patient laterally or prone can relieve extrinsic compression by shifting the mass away from the airway. This is a recognised rescue manoeuvre described in major airway management guidelines. Advancing the ETT into a main bronchus may temporarily ventilate one lung but does not relieve the compression. Increasing ventilatory parameters against a fixed mechanical obstruction will not help and risks barotrauma.

Question 72: A patient with severe TBI (GCS 6) is being monitored using continuous pressure reactivity index (PRx). The PRx–CPP plot shows a U-shaped curve with a minimum PRx of 0.04 at CPP 76 mmHg (CPPopt). The current CPP is 62 mmHg with a real-time PRx of 0.38. Which statement most accurately characterizes this patient's cerebrovascular state?

The U-shaped PRx–CPP curve confirms global loss of autoregulation at all CPP values, making CPPopt calculation unreliable
PRx of 0.38 reflects a measurement artifact; reliable autoregulation assessment requires averaging over ≥30 minutes
Autoregulation is impaired at the current CPP; cerebral blood flow is pressure-passive and the patient is operating significantly below CPPopt (Correct answer)
Autoregulation is intact; CPP 62 mmHg lies within the lower limit of the autoregulatory plateau and no intervention is needed

Correct answer: Autoregulation is impaired at the current CPP; cerebral blood flow is pressure-passive and the patient is operating significantly below CPPopt

PRx is calculated as the moving correlation coefficient between arterial blood pressure and ICP. A PRx > +0.2–0.3 indicates pressure-passive (autoregulation-impaired) cerebral blood flow, while PRx < +0.2 suggests intact autoregulation. CPPopt is the CPP at which PRx is minimized (most negative or lowest positive). Here, the current CPP of 62 mmHg yields PRx 0.38, indicating impaired autoregulation with pressure-passive CBF. The patient is operating 14 mmHg below CPPopt (76 mmHg), suggesting that increasing CPP toward the optimal value could restore autoregulatory capacity and improve cerebrovascular regulation.

Question 73: A 44-year-old patient with a large anterior mediastinal mass (5 × 7 cm) is scheduled for mediastinoscopy under general anaesthesia. Preoperative CT shows >50% tracheal cross-sectional area compression at the level of the carina. The patient is symptomatic when supine. Which of the following is the safest induction strategy?

Femoral-femoral cardiopulmonary bypass initiated before induction of general anaesthesia in all cases with >50% tracheal compression
Standard RSI with propofol and suxamethonium in the supine position, followed by orotracheal intubation
Inhalational induction with sevoflurane maintaining spontaneous ventilation, with the patient semi-recumbent or in lateral position, and rigid bronchoscopy on standby (Correct answer)
Awake flexible bronchoscopy to assess the airway, followed by intravenous induction with ketamine and rocuronium

Correct answer: Inhalational induction with sevoflurane maintaining spontaneous ventilation, with the patient semi-recumbent or in lateral position, and rigid bronchoscopy on standby

Anterior mediastinal masses with significant (>50%) tracheal compression and positional symptoms represent one of the highest-risk scenarios in thoracic anaesthesia. Loss of spontaneous ventilation and muscle tone at induction can cause complete airway collapse (the mass compresses the trachea when thoracic muscle tone is lost), leading to 'can't intubate, can't oxygenate' cardiac arrest. The gold-standard approach is inhalational induction with sevoflurane in a semi-upright or lateral decubitus position, preserving spontaneous ventilation throughout, with rigid bronchoscopy and an experienced bronchoscopist immediately available to stent the airway open if collapse occurs. RSI abolishes spontaneous breathing and muscle tone, which is contraindicated. Awake fibreoptic intubation addresses vocal cord/upper airway issues but does not protect against tracheal or carinal collapse distal to the tube tip. Pre-bypass is reserved for cases where collapse is judged inevitable or where less invasive strategies have failed — not used routinely for all >50% compression cases.

Question 74: A patient undergoing rapid sequence induction develops complete laryngospasm after intubation fails. Bag-mask ventilation is impossible and SpO2 is falling rapidly to 70%. You have applied 30–40 cmH2O of continuous positive airway pressure with no improvement. What is the most appropriate immediate next step?

Apply firm bilateral jaw thrust with 5-finger laryngospasm notch pressure
Perform immediate surgical cricothyrotomy
Administer succinylcholine 1.5 mg/kg IV to break the laryngospasm (Correct answer)
Administer propofol 0.5 mg/kg IV to deepen anaesthesia

Correct answer: Administer succinylcholine 1.5 mg/kg IV to break the laryngospasm

Complete laryngospasm unresponsive to CPAP constitutes a 'cannot intubate, cannot oxygenate' (CICO) scenario in evolution. A full intubating dose of succinylcholine (1.5 mg/kg IV) is the recommended pharmacological intervention to relax the laryngeal adductors before resorting to a surgical airway. The laryngospasm notch manoeuvre (Larson's manoeuvre) is appropriate for partial laryngospasm but has limited effect in true complete laryngospasm. Deepening anaesthesia alone is insufficient when SpO2 is critically low.

Question 75: Diabetes insipidus after transsphenoidal pituitary surgery is characterized by which laboratory finding?

Low serum sodium with large volumes of dilute urine
Low serum sodium with concentrated urine
High serum sodium with large volumes of dilute urine (Correct answer)
High serum potassium with oliguria

Correct answer: High serum sodium with large volumes of dilute urine

Central diabetes insipidus causes ADH deficiency, resulting in massive production of dilute urine, volume depletion, and hypernatremia due to free water loss.

Question 76: The transversus abdominis plane (TAP) block primarily targets which fascial plane?

Between transversus abdominis and peritoneum
Between external oblique and internal oblique
Between internal oblique and transversus abdominis (Correct answer)
Between rectus abdominis and posterior rectus sheath

Correct answer: Between internal oblique and transversus abdominis

The TAP block deposits local anesthetic between the internal oblique and transversus abdominis muscles, where the thoracolumbar nerves (T6-L1) travel.

Question 77: During a stellate ganglion block, Horner's syndrome confirms successful blockade. Which triad of signs characterizes Horner's syndrome?

Exophthalmos, tachycardia, and miosis
Ptosis, miosis, and anhidrosis (Correct answer)
Ptosis, enophthalmos, and hypertension
Mydriasis, ptosis, and facial flushing

Correct answer: Ptosis, miosis, and anhidrosis

Horner's syndrome results from sympathetic blockade and manifests as ptosis (drooping eyelid), miosis (pupillary constriction), and anhidrosis (loss of sweating) on the ipsilateral face.

Question 78: The recommended tidal volume during one-lung ventilation to minimize ventilator-induced lung injury is:

3-4 mL/kg IBW
10-12 mL/kg IBW
5-6 mL/kg IBW (Correct answer)
8-10 mL/kg IBW

Correct answer: 5-6 mL/kg IBW

Current lung-protective OLV strategy uses tidal volumes of 5-6 mL/kg ideal body weight to prevent overdistension of the ventilated lung.

Question 79: During anaesthesia for transsphenoidal resection of a macroprolactinoma, the patient suddenly develops polyuria with urine output of 850 mL/hour, urine osmolality of 85 mOsm/kg, and serum sodium rising to 152 mEq/L within 90 minutes. Which is the MOST appropriate immediate pharmacological intervention?

Intravenous 0.45% saline at 250 mL/hour to replace free water deficit
Intranasal vasopressin 10 units as a bolus to achieve immediate antidiuresis
Intravenous desmopressin (dDAVP) 1–2 µg and switch maintenance fluids to 5% dextrose (Correct answer)
Oral hydrochlorothiazide via nasogastric tube to reduce free water clearance

Correct answer: Intravenous desmopressin (dDAVP) 1–2 µg and switch maintenance fluids to 5% dextrose

The clinical picture — acute polyuria, hypotonic urine, and rising serum sodium — is consistent with intraoperative central diabetes insipidus from pituitary stalk manipulation during transsphenoidal surgery. Desmopressin (dDAVP) is the agent of choice: its selective V2-receptor agonism produces antidiuresis without significant vasopressor (V1) effects, and 1–2 µg IV achieves rapid effect within 15–30 minutes. Switching maintenance to 5% dextrose provides free water to begin correcting the hypernatraemia without a sodium load. Hypotonic saline alone does not address the underlying ADH deficiency and will not halt the massive urinary losses. Intranasal vasopressin is impractical intraoperatively and non-selective. Oral agents are inappropriate in the acute intraoperative setting.

Question 80: Which ion channel is primarily responsible for the plateau phase (phase 2) of the ventricular action potential?

Inward rectifier potassium channels
Transient outward potassium channels
Fast sodium channels
L-type calcium channels (Correct answer)

Correct answer: L-type calcium channels

L-type (long-lasting) calcium channels carry slow inward calcium current responsible for the prolonged plateau phase 2 of the ventricular action potential.

Question 81: A patient with Child-Pugh C cirrhosis and INR 2.9 is scheduled for emergency laparotomy. The surgical team requests FFP to 'correct' the coagulopathy before incision. Which statement BEST justifies why a markedly elevated INR in end-stage liver disease does NOT reliably predict haemorrhagic risk?

The PT/INR reagents were calibrated for warfarin monitoring using an ISI derived from warfarin-treated patients, making the assay systematically unreliable in liver disease
Thrombocytopenia in cirrhosis is offset by markedly elevated von Willebrand factor, restoring primary haemostasis independently of the coagulation cascade
Parallel reduction of both procoagulant and anticoagulant proteins (Protein C, Protein S, antithrombin III) creates a 'rebalanced haemostasis' that the PT/INR cannot capture (Correct answer)
Hepatic production of fibrinolytic inhibitors such as PAI-1 is preserved even in decompensated cirrhosis, preventing clinically significant fibrinolysis

Correct answer: Parallel reduction of both procoagulant and anticoagulant proteins (Protein C, Protein S, antithrombin III) creates a 'rebalanced haemostasis' that the PT/INR cannot capture

The concept of 'rebalanced haemostasis' in end-stage liver disease is critical. The liver produces both procoagulant (factors II, V, VII, X) and anticoagulant proteins (Protein C, Protein S, antithrombin III). Both are reduced proportionally in cirrhosis. The PT/INR only assesses procoagulant deficiency and is therefore blind to the simultaneous loss of natural anticoagulants. The net haemostatic state is far more nuanced than a simple INR-based assessment implies — many patients with grossly elevated INRs are neither coagulopathic nor hypercoagulable, but precariously balanced. VWF is indeed elevated (correct concept in option C), but the BEST explanation for INR unreliability is the rebalanced haemostasis concept captured in option B.

Question 82: In a diagnostic accuracy study, the area under the ROC curve (AUC) is reported as 0.50. How should this be interpreted?

The test performs no better than chance (random guessing) (Correct answer)
The test correctly identifies 50% of cases
The test has 50% sensitivity and 50% specificity
The test is perfect

Correct answer: The test performs no better than chance (random guessing)

An AUC of 0.50 corresponds to the diagonal line of the ROC curve, meaning the test discriminates no better than flipping a coin — it has no diagnostic value. An AUC of 1.0 is a perfect test; AUC ≥ 0.70 is generally considered acceptable. AUC represents the probability that the test correctly ranks a randomly chosen diseased individual above a randomly chosen non-diseased individual.

Question 83: A 55-year-old patient with known Type 2 diabetes is admitted to the ICU with septic shock secondary to necrotizing fasciitis. Despite adequate fluid resuscitation, MAP remains 58 mmHg on norepinephrine 0.35 μg/kg/min. Vasopressin 0.03 units/min is added. Cortisol stimulation testing reveals a delta cortisol of 4 μg/dL after 250 μg ACTH. The intensivist initiates hydrocortisone 200 mg/day by continuous infusion. Four hours later, the nurse notes capillary glucose of 18.2 mmol/L (328 mg/dL). What is the MOST physiologically accurate explanation for this glucose elevation in this specific context?

Hydrocortisone causes direct pancreatic beta-cell apoptosis, reducing endogenous insulin production within hours of administration
Hydrocortisone induces hepatic gluconeogenesis and peripheral insulin resistance, compounded by counter-regulatory catecholamine effects and impaired insulin secretion due to vasopressin-mediated V1b receptor inhibition on pancreatic beta cells (Correct answer)
Vasopressin stimulates glycogenolysis via V2 receptors in hepatocytes, directly releasing stored glucose
Norepinephrine blocks GLUT-4 translocation in skeletal muscle via alpha-1 receptor activation, preventing insulin-mediated glucose uptake independently of corticosteroid effects

Correct answer: Hydrocortisone induces hepatic gluconeogenesis and peripheral insulin resistance, compounded by counter-regulatory catecholamine effects and impaired insulin secretion due to vasopressin-mediated V1b receptor inhibition on pancreatic beta cells

Hydrocortisone causes hyperglycemia through multiple mechanisms: it stimulates hepatic gluconeogenesis and glycogenolysis, promotes peripheral insulin resistance by reducing GLUT-4 expression and post-receptor signaling, and enhances the hyperglycemic effects of catecholamines. Additionally, vasopressin acts on V1b (V3) receptors on pancreatic beta cells to inhibit glucose-stimulated insulin secretion, contributing to reduced endogenous insulin response. This multi-mechanism explanation is the most complete. Vasopressin acts via V1b not V2 in the pancreas; V2 receptors are renal and mediate water retention, not glycogenolysis. Alpha-1 receptor activation by norepinephrine does cause some glucose elevation but GLUT-4 inhibition is not the primary mechanism cited. Hydrocortisone does not cause acute beta-cell apoptosis within hours.

Question 84: A 70-year-old patient with New York Heart Association Class III heart failure (EF 25%) develops cardiogenic shock with a cardiac index of 1.6 L/min/m² and a pulmonary capillary wedge pressure of 28 mmHg. Dopamine is started at 10 mcg/kg/min. Six hours later, the patient develops new atrial fibrillation with rapid ventricular response and the cardiac index drops to 1.3 L/min/m². Which statement about the use of dopamine in cardiogenic shock is MOST consistent with current evidence and pharmacology?

Dopamine should be uptitrated to 20 mcg/kg/min to achieve sufficient beta-1 stimulation and improve cardiac output before considering mechanical circulatory support
Dopamine at 10 mcg/kg/min acts primarily on dopaminergic receptors to increase renal perfusion without significant cardiac effects
Dopamine at >5 mcg/kg/min has a predominantly alpha-1 adrenergic effect, and its beta-1 activity increases myocardial oxygen demand, predisposing to arrhythmias — switching to norepinephrine reduces arrhythmia risk (Correct answer)
The atrial fibrillation is unrelated to dopamine; immediate DC cardioversion should be performed before reassessing the vasopressor regimen

Correct answer: Dopamine at >5 mcg/kg/min has a predominantly alpha-1 adrenergic effect, and its beta-1 activity increases myocardial oxygen demand, predisposing to arrhythmias — switching to norepinephrine reduces arrhythmia risk

The SOAP II trial (De Backer et al., NEJM 2010) demonstrated that dopamine — compared to norepinephrine — was associated with a significantly higher rate of arrhythmic events (primarily atrial fibrillation) in patients with cardiogenic shock. At doses >5–10 mcg/kg/min, dopamine has prominent beta-1 adrenergic effects that increase heart rate and myocardial oxygen demand, and also stimulates norepinephrine release from sympathetic terminals. This combination predisposes to tachyarrhythmias. Current guidelines (ESC 2021) recommend norepinephrine over dopamine in cardiogenic shock due to lower arrhythmia risk. Option B is incorrect — 'renal dose' dopaminergic effects are physiologically negligible at 10 mcg/kg/min relative to adrenergic activity. Option C is dangerous — escalating dopamine in the context of new AF would worsen haemodynamic compromise. Option D ignores the causative pharmacological relationship.

Question 85: A 70-year-old patient with stable heart failure (EF 35%) is scheduled for elective total hip replacement. According to ESC 2022 perioperative guidelines, which investigation adds the most diagnostic value for preoperative cardiac risk stratification in this scenario?

Routine preoperative troponin measurement
Echocardiography to reassess ventricular function if no echo in the past 12 months (Correct answer)
Routine preoperative coronary angiography
Cardiopulmonary exercise testing (CPEX) in all patients over 65

Correct answer: Echocardiography to reassess ventricular function if no echo in the past 12 months

In a patient with known heart failure scheduled for intermediate-risk surgery, reassessing ventricular function with echocardiography is appropriate if there has been a recent clinical change or no recent echo is available (within approximately 12 months). This guides anaesthetic planning (choice of agent, haemodynamic targets, need for invasive monitoring). CPEX is indicated for high-risk or uncertain functional capacity cases. Routine coronary angiography and troponin are not first-line for preoperative evaluation in stable heart failure.

Question 86: In a patient anaesthetised with 68% nitrous oxide, an infrared sidestream capnograph displays ETCO₂ of 6.8 kPa while arterial blood gas confirms PaCO₂ of 5.4 kPa. Beyond the normal a-ETCO₂ gradient, which physical mechanism most specifically accounts for the capnograph's overestimation of CO₂?

Raman backscattering from N₂O creating spurious signal at the CO₂ detection wavelength
Collision (pressure) broadening of the CO₂ infrared absorption band caused by N₂O molecules (Correct answer)
Doppler broadening of the CO₂ absorption spectrum due to high gas velocities in the sampling line
Thermal emission from N₂O molecules generating background infrared noise at 4.26 µm

Correct answer: Collision (pressure) broadening of the CO₂ infrared absorption band caused by N₂O molecules

Collision broadening (pressure broadening) occurs when N₂O molecules collide with CO₂ molecules, widening their infrared absorption band and increasing apparent absorbance at the 4.26 µm CO₂ detection wavelength. High N₂O concentrations therefore cause the capnograph to overread ETCO₂. Modern capnographs incorporate correction algorithms when N₂O is detected simultaneously; uncorrected or legacy devices may exhibit clinically significant error. Doppler broadening (caused by thermal molecular motion) is a separate phenomenon not specific to N₂O–CO₂ mixtures. Raman-scatter-based devices handle gas analysis differently and are not susceptible to this particular error.

Question 87: Which of the following chronic medications should routinely be CONTINUED on the morning of elective non-cardiac surgery?

ACE inhibitors / angiotensin receptor blockers
Warfarin
Metformin (before major abdominal surgery)
Chronically prescribed beta-blockers (Correct answer)

Correct answer: Chronically prescribed beta-blockers

Chronically prescribed beta-blockers must be continued perioperatively; abrupt withdrawal risks rebound hypertension, tachycardia, and myocardial ischaemia. Metformin is typically withheld ≥ 24–48 hours before major surgery due to lactic acidosis risk in the setting of haemodynamic instability. ACE inhibitors/ARBs are generally withheld on the morning of surgery to reduce the risk of refractory intraoperative hypotension. Warfarin requires bridging or cessation based on thrombotic and haemorrhagic risk assessment.

Question 88: In ultrasound-guided femoral nerve block, where is the nerve typically located relative to the femoral artery?

Lateral to the femoral artery, beneath the fascia iliaca (Correct answer)
Medial to the femoral artery, within the femoral sheath
Deep to the femoral artery within the adductor canal
Posterior to the femoral vein

Correct answer: Lateral to the femoral artery, beneath the fascia iliaca

The femoral nerve lies lateral to the femoral artery and deep to the fascia iliaca (but outside the femoral sheath) at the inguinal level.

Question 89: Bronchospasm during thoracic surgery is LEAST likely to respond to which intervention?

IV ketamine
IV rocuronium (Correct answer)
Inhaled salbutamol via the breathing circuit
Deepening volatile anesthetic depth

Correct answer: IV rocuronium

Neuromuscular blocking agents have no bronchodilatory effect; bronchospasm requires agents that relax airway smooth muscle via adrenergic or anti-cholinergic mechanisms.

Question 90: In a patient with hypertrophic obstructive cardiomyopathy (HOCM) under general anaesthesia, acute systemic hypotension occurs. A registrar administers phenylephrine (200 mcg IV bolus). Five minutes later, the patient develops syncope with LVOT gradient increasing from 40 to 110 mmHg. What is the most likely explanation?

Pure alpha-1 agonism raised aortic pressure, increasing ventricular wall stress, triggering a Bezold-Jarisch reflex that worsened obstruction
Phenylephrine caused coronary vasospasm, inducing ischaemia of the septum and worsening hypertrophy-driven obstruction acutely
Phenylephrine's alpha-1-mediated increase in SVR reduced forward flow, but the simultaneous negative chronotropic effect increased time for systolic anterior motion (SAM) to develop (Correct answer)
Reflex bradycardia from phenylephrine's baroreceptor activation prolonged diastole, increased LV filling and end-diastolic volume, paradoxically worsening SAM and LVOT obstruction by increasing contractility-driven obstruction

Correct answer: Phenylephrine's alpha-1-mediated increase in SVR reduced forward flow, but the simultaneous negative chronotropic effect increased time for systolic anterior motion (SAM) to develop

Phenylephrine, a pure alpha-1 agonist, raises SVR and arterial pressure — which is generally desirable in HOCM to increase afterload and reduce obstruction. However, via baroreceptor reflex, it causes significant reflex bradycardia. The prolonged diastolic filling time increases LV end-diastolic volume, and the slower heart rate increases time available per systole for SAM to develop. Paradoxically, in a setting of already elevated contractility, the combination of reflex bradycardia + increased preload may worsen the dynamic obstruction. While the increase in SVR helps, the net effect in this case was worsening. This subtle interaction is clinically important: phenylephrine is still preferred over vasodilators, but the reflex bradycardia component can worsen dynamic obstruction.

Question 91: Which nerve is most commonly injured during interscalene brachial plexus block?

Phrenic nerve (Correct answer)
Long thoracic nerve
Recurrent laryngeal nerve
Suprascapular nerve

Correct answer: Phrenic nerve

The phrenic nerve (C3-C5) runs adjacent to the brachial plexus at the interscalene level and is blocked in nearly 100% of cases, causing ipsilateral hemidiaphragm paresis.

Question 92: Which of the following anesthetic agents is known to most significantly inhibit hypoxic pulmonary vasoconstriction (HPV), potentially worsening oxygenation during one-lung ventilation?

Propofol
Nitroglycerin (Correct answer)
Desflurane
Fentanyl

Correct answer: Nitroglycerin

Nitroglycerin, a potent vasodilator and nitric oxide donor, is a significant inhibitor of hypoxic pulmonary vasoconstriction (HPV). By attenuating the HPV response in the non-ventilated lung, it can increase intrapulmonary shunt and worsen hypoxemia during one-lung ventilation. While volatile anesthetics like desflurane can also inhibit HPV, this effect is dose-dependent and generally less profound than that of direct vasodilators. Propofol and opioids such as fentanyl have minimal to no clinically significant effect on HPV.

Question 93: In capnography, a sustained elevated baseline (above zero) between breaths most likely indicates:

Rebreathing of CO₂ due to exhausted soda lime or defective expiratory valve (Correct answer)
Pulmonary embolism
Esophageal intubation
Bronchospasm causing gas trapping

Correct answer: Rebreathing of CO₂ due to exhausted soda lime or defective expiratory valve

An elevated baseline (>0 mmHg) between inspirations signifies inspired CO₂, classically caused by exhausted absorber or a stuck expiratory valve.

Question 94: During posterior fossa surgery in the sitting position, a sudden increase in end-tidal CO2 from 35 to 28 mmHg, a 15% drop in ETCO2, a mill-wheel murmur on precordial Doppler, and a drop in SpO2 to 90% occur simultaneously. Transesophageal echocardiography reveals air in the right ventricle. Which sequence of interventions is MOST appropriate?

Immediately convert to supine position → 100% FiO2 → cardiac massage → adrenaline 1 mg IV
Flood surgical field with saline → compress jugular veins → aspirate air via central venous catheter → left lateral Trendelenburg position (Correct answer)
Nitrous oxide discontinuation only, as small VAE is self-limiting in sitting position
Aspirate air via central venous catheter → PEEP 10 cmH2O → notify surgeon → maintain sitting position

Correct answer: Flood surgical field with saline → compress jugular veins → aspirate air via central venous catheter → left lateral Trendelenburg position

Management of significant venous air embolism (VAE) follows a stepwise approach: (1) Flood the surgical field to stop air entrainment; (2) Compress jugular veins bilaterally (raises venous pressure, reducing air entry); (3) Aspirate via a right atrial/CVP catheter (positioned at the RA–SVC junction) to remove entrained air; (4) Place in left lateral Trendelenburg to trap air in the right ventricle apex and prevent RV outflow obstruction. Supine conversion with CPR is reserved for cardiovascular collapse. PEEP alone cannot remove air. Discontinuing N2O (if used) is correct but insufficient alone. The scenario describes haemodynamically significant VAE requiring active intervention.

Question 95: A bronchial blocker is preferred over a double-lumen tube in which clinical scenario?

Surgeon requiring rapid lung re-expansion
Patient with a difficult airway already intubated with a size 7.5 single-lumen tube (Correct answer)
Left pneumonectomy planned
Need for postoperative differential lung ventilation

Correct answer: Patient with a difficult airway already intubated with a size 7.5 single-lumen tube

A bronchial blocker can be advanced through an existing single-lumen ETT under fiberoptic guidance, avoiding the need to exchange to a larger tube in a difficult airway.

Question 96: A 61-year-old with alcoholic cirrhosis (MELD score 22) undergoes elective transjugular intrahepatic portosystemic shunt (TIPS) insertion for refractory variceal bleeding. Anaesthetic consent is being obtained. Which complication should be weighted as MOST likely to occur in the first 48 hours post-procedure?

New or worsening hepatic encephalopathy due to portosystemic diversion of ammonia-rich blood bypassing hepatic detoxification (Correct answer)
Pulmonary hypertension from sudden increase in right heart preload causing acute right ventricular failure
Acute hepatic artery thrombosis secondary to haemodynamic redistribution requiring emergency liver transplantation
Type 1 hepatorenal syndrome precipitated by iodinated contrast-mediated tubular toxicity

Correct answer: New or worsening hepatic encephalopathy due to portosystemic diversion of ammonia-rich blood bypassing hepatic detoxification

TIPS creates a direct communication between the portal vein and hepatic vein, intentionally shunting portal blood away from the hepatic parenchyma. While this decompresses the portal system, it simultaneously delivers gut-derived nitrogenous products (primarily ammonia) directly into the systemic circulation without hepatic first-pass metabolism. Hepatic encephalopathy (HE) develops in 25–45% of patients post-TIPS, and existing HE worsens significantly. Patients with MELD >15, pre-existing HE, or older age are at highest risk. While pulmonary hypertension can occur due to increased cardiac output (a recognised long-term complication), it is far less acute. AHT is a transplant complication. HRS type 1 is more typically precipitated by infection or GI bleeding, not contrast alone.

Question 97: The most common immediate complication of percutaneous dilatational tracheostomy (PDT) is:

Bleeding at the insertion site (Correct answer)
Tracheoesophageal fistula
Accidental decannulation during the procedure
Tracheal stenosis requiring surgical repair

Correct answer: Bleeding at the insertion site

Bleeding at the tracheostomy site is the most frequent immediate complication of PDT, typically minor and controlled with local pressure, though significant hemorrhage can occur if anterior jugular veins or thyroid vessels are injured.

Question 98: The WHO Surgical Safety Checklist is structured around three pause points during the surgical episode. Which of the following correctly identifies all three?

Pre-operative ward round, anaesthetic room check, recovery room handover
Consent, anaesthetic machine check, post-operative review
Sign In (before induction), Time Out (before skin incision), Sign Out (before patient leaves theatre) (Correct answer)
Pre-admission, pre-induction, post-operative

Correct answer: Sign In (before induction), Time Out (before skin incision), Sign Out (before patient leaves theatre)

The WHO Surgical Safety Checklist (introduced 2008) comprises: (1) Sign In — before induction of anaesthesia, confirming patient identity, consent, allergies, airway assessment, and anaesthetic machine check; (2) Time Out — before skin incision, confirming team introductions, procedure, site, imaging, and antibiotic prophylaxis; (3) Sign Out — before the patient leaves theatre, confirming instrument/swab counts, specimen labelling, and recovery plan. Systematic use has been shown to reduce surgical mortality and complication rates.

Question 99: Which volatile anesthetic is associated with the highest risk of laryngospasm in pediatric patients?

Desflurane (Correct answer)
Isoflurane
Sevoflurane
Halothane

Correct answer: Desflurane

Desflurane is the most pungent volatile agent and is associated with the highest incidence of airway reactivity, coughing, and laryngospasm in children.

Question 100: The coronary perfusion pressure is defined as:

MAP minus PCWP
Aortic diastolic pressure minus LVEDP (Correct answer)
Systolic BP minus PCWP
MAP minus CVP

Correct answer: Aortic diastolic pressure minus LVEDP

Coronary perfusion pressure = aortic diastolic pressure minus left ventricular end-diastolic pressure, as most LV coronary flow occurs during diastole.

Question 101: At what postconceptional age is it generally safe to perform elective surgery without overnight monitoring for apnea in a premature infant?

56 weeks (Correct answer)
50 weeks
44 weeks
60 weeks

Correct answer: 56 weeks

Most guidelines recommend 56–60 weeks postconceptional age before elective surgery without mandatory overnight apnea monitoring, though thresholds vary by institution.

Question 102: During anaesthesia for a living-donor renal transplant recipient, the transplanted kidney is reperfused. The anaesthesiologist notes an acute rise in serum potassium from 4.2 to 6.8 mmol/L on ABG. Which combination of interventions is MOST appropriate as immediate management, assuming the patient is haemodynamically stable with no ECG changes yet?

IV salbutamol nebulisation and furosemide to promote renal potassium excretion
IV calcium gluconate 10 mL 10%, insulin 10 units with 50 mL 50% dextrose, and sodium bicarbonate 50 mmol (Correct answer)
Immediate haemodialysis via the transplant team
IV calcium chloride 10 mL 10% only — membrane stabilisation is sufficient

Correct answer: IV calcium gluconate 10 mL 10%, insulin 10 units with 50 mL 50% dextrose, and sodium bicarbonate 50 mmol

Reperfusion hyperkalaemia during renal transplantation results from release of high-potassium preservation solution (e.g. University of Wisconsin or Custodiol solution, K+ ~120 mmol/L) and ischaemic metabolites from the graft. A jump to 6.8 mmol/L requires prompt, multimodal management: (1) Calcium gluconate (or chloride) for immediate cardiac membrane stabilisation; (2) Insulin + glucose to shift K+ intracellularly (most reliable rapid mechanism); (3) Sodium bicarbonate to alkalinise plasma and further shift K+ intracellularly — especially useful in the concurrent metabolic acidosis of reperfusion. While salbutamol also shifts K+ intracellularly, it causes tachycardia and is not first-line in the OR. Furosemide requires a functioning kidney for effect (the transplant may not yet be working). Immediate dialysis is not warranted without ECG changes and is not logistically immediate intraoperatively.

Question 103: Which local anesthetic has the longest duration of action for peripheral nerve blocks?

Ropivacaine
Mepivacaine
Lidocaine
Bupivacaine (Correct answer)

Correct answer: Bupivacaine

Bupivacaine provides the longest duration (up to 12-18 hours for nerve blocks), though ropivacaine has a similar but slightly shorter duration with a better safety profile.

Question 104: During video-assisted thoracoscopic surgery (VATS), inadequate lung collapse despite a correctly positioned DLT is most efficiently addressed by:

Applying 5 cmH2O CPAP to the collapsed lung
Insufflating CO2 into the pleural space at low pressure (Correct answer)
Increasing PEEP on the ventilated lung
Switching to a single-lumen tube with bronchial blocker

Correct answer: Insufflating CO2 into the pleural space at low pressure

Low-pressure CO2 insufflation (up to 8 mmHg) into the pleural cavity rapidly collapses the operative lung and improves surgical visualization when passive collapse is incomplete.

Question 105: A 28-week preterm neonate (1.1 kg) requires emergency laparotomy for necrotizing enterocolitis. Intraoperatively, you notice persistent metabolic acidosis despite adequate ventilation. Which of the following is the MOST likely cause in this specific scenario?

Hypothermia-induced impaired lactate clearance (Correct answer)
Excessive crystalloid causing hyperchloremic acidosis
Sepsis-driven mitochondrial dysfunction with cytopathic hypoxia
Intraoperative hypoglycemia from depleted glycogen stores

Correct answer: Hypothermia-induced impaired lactate clearance

Premature neonates have extremely limited capacity for thermogenesis and virtually no brown adipose tissue reserves at 28 weeks. The open abdominal cavity during laparotomy, combined with wet surgical drapes, cold irrigation fluids, and a large surface-area-to-volume ratio leads to rapid hypothermia. Hypothermia impairs hepatic lactate clearance (the liver is the primary lactate consumer), reduces cardiac output, and shifts the oxyhemoglobin dissociation curve leftward — all compounding a persistent metabolic acidosis that will not respond to bicarbonate without addressing the temperature deficit. While the other options are plausible, hypothermia is the most immediate and correctable cause uniquely amplified in this gestational age and surgical context.

Question 106: During cardiopulmonary bypass, a patient receives protamine to reverse heparin. Pulmonary artery pressure rises from 22/10 to 54/30 mmHg and systemic arterial pressure falls sharply. Complement activation is confirmed. Which receptor pathway is the PRIMARY mediator of the pulmonary vasoconstriction in this protamine reaction?

Thromboxane A2 receptors on pulmonary vascular smooth muscle, activated by TXA2 released from complement-triggered platelet and macrophage activation (Correct answer)
Histamine H1 receptors causing direct pulmonary arteriolar constriction via IP3-mediated calcium release
Endothelin-1 receptors (ET-A) upregulated by complement anaphylatoxins C3a and C5a
Alpha-1 adrenoceptors stimulated by catecholamine surge from anaphylactic mast cell degranulation

Correct answer: Thromboxane A2 receptors on pulmonary vascular smooth muscle, activated by TXA2 released from complement-triggered platelet and macrophage activation

Protamine-heparin complexes activate complement via the classical pathway, generating C3a and C5a. These anaphylatoxins trigger pulmonary intravascular macrophages and platelets to release thromboxane A2 (TXA2). TXA2 binds TP receptors on pulmonary vascular smooth muscle causing intense vasoconstriction — the dominant mechanism in complement-mediated protamine pulmonary hypertension. Histamine contributes to systemic vasodilation rather than pulmonary vasoconstriction. ET-1 elevation is slower and not the acute mediator. Catecholamine surge is secondary.

Question 107: A 58-year-old patient with a biochemically confirmed phaeochromocytoma is scheduled for laparoscopic adrenalectomy. Despite 3 weeks of alpha-blockade with phenoxybenzamine, intraoperative hypertensive crisis (BP 240/130 mmHg) occurs during tumour manipulation. After IV phentolamine fails to control BP adequately, which agent is most appropriate as second-line therapy?

IV nicardipine as a titratable calcium channel blocker (Correct answer)
IV esmolol to address reflex tachycardia and reduce BP
IV sodium nitroprusside (SNP) as a direct vasodilator
IV magnesium sulphate to inhibit catecholamine release

Correct answer: IV nicardipine as a titratable calcium channel blocker

Nicardipine, a dihydropyridine calcium channel blocker, is highly effective as a second-line agent for phaeochromocytoma-related hypertensive crisis. It provides rapid, titratable, predictable vasodilation without the risk of cyanide toxicity associated with sodium nitroprusside (problematic in prolonged use or hepatic dysfunction). SNP remains an option but carries toxicity risk. Esmolol (a beta-blocker) must NEVER be used without adequate alpha-blockade in phaeochromocytoma, as unopposed alpha-stimulation can paradoxically worsen hypertension — and even with prior phenoxybenzamine, adding a beta-blocker during active catecholamine surge is dangerous. Magnesium can reduce catecholamine release and is used as an adjunct but is not potent enough as a sole second-line agent for severe crisis.

Question 108: Which mechanism explains the analgesic effect of intrathecal clonidine?

Sodium channel blockade of primary afferent fibers
Mu-opioid receptor activation in the dorsal horn
Alpha-2 adrenergic receptor activation inhibiting substance P release in the spinal cord (Correct answer)
NMDA receptor blockade at the dorsal horn

Correct answer: Alpha-2 adrenergic receptor activation inhibiting substance P release in the spinal cord

Clonidine activates spinal alpha-2 adrenergic receptors on presynaptic C-fiber terminals, inhibiting substance P and glutamate release, and on postsynaptic dorsal horn neurons, producing hyperpolarization and analgesia.

Question 109: Which component of the massive transfusion protocol is primarily given to replace fibrinogen?

Fresh frozen plasma
Cryoprecipitate (Correct answer)
Platelet concentrate
Packed red blood cells

Correct answer: Cryoprecipitate

Cryoprecipitate is rich in fibrinogen, Factor VIII, von Willebrand factor, and Factor XIII.

Question 110: In thoracic epidural analgesia for open thoracotomy, the optimal dermatomal level of catheter insertion is:

T4-T8 (Correct answer)
T1-T4
C7-T1
T8-T12

Correct answer: T4-T8

Thoracic epidural catheters placed at T4-T8 provide analgesia centered on the thoracotomy incision, optimizing pain control and preserving respiratory function.

Question 111: What is the primary concern with using nitrous oxide in neonates with suspected bowel obstruction?

Impaired hypoxic pulmonary vasoconstriction
Increased risk of laryngospasm
Cardiotoxicity in the neonatal myocardium
Diffusion into air-filled spaces causing bowel distension (Correct answer)

Correct answer: Diffusion into air-filled spaces causing bowel distension

Nitrous oxide diffuses into closed air-containing spaces 30 times faster than nitrogen exits, causing distension of obstructed bowel loops and worsening the surgical field.

Question 112: A 55-year-old patient with sepsis develops moderate-to-severe ARDS, with a PaO2/FiO2 ratio of 110 mmHg. The patient is ventilated according to a lung-protective strategy (6 mL/kg predicted body weight, plateau pressure < 30 cmH2O). Which of the following adjunctive therapies has demonstrated the most significant mortality benefit in this patient population?

High-frequency oscillatory ventilation (HFOV)
Inhaled nitric oxide
Routine administration of high-dose corticosteroids
Prone positioning for at least 16 hours per day (Correct answer)

Correct answer: Prone positioning for at least 16 hours per day

The PROSEVA trial demonstrated a significant reduction in both 28-day and 90-day mortality when prone positioning, for at least 16 hours per day, was applied early to patients with severe ARDS (PaO2/FiO2 < 150 mmHg). [7, 23, 28] Other interventions like HFOV and inhaled nitric oxide have not consistently shown a mortality benefit, and routine high-dose corticosteroids are not recommended for most ARDS patients.

Question 113: Within two hours of receiving a transfusion of packed red blood cells, a 65-year-old ICU patient develops acute respiratory distress, hypoxemia (SpO2 85% on 60% O2), and bilateral infiltrates on chest X-ray. Her blood pressure is 90/50 mmHg, and there are no signs of fluid overload such as jugular venous distension or peripheral edema. Which of the following is the most likely diagnosis?

Anaphylactic Reaction
Transfusion-Associated Circulatory Overload (TACO)
Acute Hemolytic Transfusion Reaction
Transfusion-Related Acute Lung Injury (TRALI) (Correct answer)

Correct answer: Transfusion-Related Acute Lung Injury (TRALI)

The clinical picture of acute hypoxemia and bilateral pulmonary edema occurring within 6 hours of transfusion, in the absence of signs of circulatory overload (e.g., hypotension rather than hypertension), is characteristic of Transfusion-Related Acute Lung Injury (TRALI). [11, 23, 34] TRALI is a form of non-cardiogenic pulmonary edema. [10, 34] In contrast, Transfusion-Associated Circulatory Overload (TACO) is a cardiogenic or hydrostatic pulmonary edema, typically associated with signs of fluid overload like hypertension and elevated central venous pressure. [36, 42] Anaphylaxis often involves bronchospasm and urticaria, and an acute hemolytic reaction typically presents with fever, chills, hemoglobinuria, and flank pain.

Question 114: What is the maximum recommended dose of lidocaine with epinephrine for peripheral nerve block in adults?

5 mg/kg
3 mg/kg
7 mg/kg (Correct answer)
9 mg/kg

Correct answer: 7 mg/kg

With epinephrine (1:200,000), the maximum safe dose of lidocaine is 7 mg/kg due to the vasoconstrictive effect slowing systemic absorption.

Question 115: Which of the following physiological mechanisms BEST explains the phenomenon of 'luxury perfusion' seen on cerebral blood flow studies after reperfusion of an ischaemic penumbra, and what is its primary risk?

Loss of cerebrovascular autoregulation causing pressure-passive hyperaemia, risking haemorrhagic transformation (Correct answer)
Vasospasm-induced compensatory hyperperfusion with risk of delayed ischaemia
Intact autoregulation with maximal vasodilation leading to metabolic uncoupling and oedema
CO2-driven vasodilatation from tissue acidosis causing benign temporary hyperaemia

Correct answer: Loss of cerebrovascular autoregulation causing pressure-passive hyperaemia, risking haemorrhagic transformation

Luxury perfusion occurs when ischaemia-injured cerebrovascular smooth muscle loses autoregulatory capacity. Blood flow then becomes passively pressure-dependent, producing CBF that exceeds metabolic demand (CMRO2). The primary clinical danger is that the disrupted blood-brain barrier combined with elevated perfusion pressure promotes haemorrhagic transformation of the infarct. This is the mechanistic basis for blood pressure control targets after reperfusion therapy (thrombolysis/thrombectomy) in stroke and after carotid endarterectomy hyperperfusion syndrome.

Question 116: In a patient with a large right-sided bronchopleural fistula (BPF) requiring general anesthesia, which sequence of induction and airway management is MOST appropriate to prevent tension pneumothorax and ensure lung isolation BEFORE positive pressure ventilation?

Rapid sequence induction with succinylcholine, then left-sided double-lumen tube (DLT) placement after intubation
Awake fiberoptic intubation with a left-sided DLT under spontaneous ventilation, confirming position before induction of general anesthesia
Inhalational induction with sevoflurane maintaining spontaneous ventilation, followed by left-sided DLT with bronchoscopic confirmation (Correct answer)
Insertion of a right-sided chest drain under local anesthesia followed by standard RSI with orotracheal tube and bronchial blocker

Correct answer: Inhalational induction with sevoflurane maintaining spontaneous ventilation, followed by left-sided DLT with bronchoscopic confirmation

With a large BPF, positive pressure ventilation before lung isolation risks converting a communicating fistula into a tension pneumothorax. Inhalational induction maintaining spontaneous respiration preserves the patient's own airway pressures (which are lower) until the DLT is placed and the fistula side is isolated. Awake FOI with a DLT is also acceptable but technically demanding with a large DLT in an awake patient. RSI before isolation risks immediate barotrauma. A chest drain alone does not prevent ventilatory loss through the fistula. The left-sided DLT is chosen because right-sided DLTs have poor endobronchial fit variability and a BPF is already on the right.

Question 117: The 'duty of candour' in anaesthetic practice requires a clinician to do which of the following when an intraoperative complication affects a patient?

Maintain confidentiality about the complication to protect other team members from blame
Only disclose the complication if the patient asks specifically about it
Report the incident to the police within 24 hours
Proactively inform the patient (or their representative) that something went wrong, apologise, and explain what is known and what will be done (Correct answer)

Correct answer: Proactively inform the patient (or their representative) that something went wrong, apologise, and explain what is known and what will be done

Duty of candour — now enshrined in professional codes across Europe (GMC, professional societies) and statute in some jurisdictions — requires healthcare professionals to be open and honest with patients when things go wrong. This includes: telling the patient something has gone wrong, offering an apology, explaining what happened and its short-term effects, and outlining the steps being taken to minimise harm and prevent recurrence. Candour applies proactively, not only in response to patient enquiry.

Question 118: Which intraoperative blood glucose target is recommended for most surgical patients to balance risks of hypoglycemia and hyperglycemia?

60–80 mg/dL
80–110 mg/dL
180–220 mg/dL
140–180 mg/dL (Correct answer)

Correct answer: 140–180 mg/dL

Current perioperative guidelines recommend a blood glucose target of 140–180 mg/dL, as tight control (80–110) increases hypoglycemia risk without improving outcomes in most surgical patients.

Question 119: Video laryngoscopy compared to direct laryngoscopy for anticipated difficult airways:

Consistently results in faster intubation times across all operators
Is contraindicated when blood or secretions are present in the airway
Improves glottic visualization but tube delivery can still be challenging (Correct answer)
Always provides a superior glottic view and always improves intubation success equally

Correct answer: Improves glottic visualization but tube delivery can still be challenging

Video laryngoscopy reliably improves glottic visualization, but this does not automatically translate to easier tube delivery — particularly with hyperangulated blades where directing the tube into the trachea requires additional technique.

Question 120: A patient with known immune thrombocytopenic purpura (ITP) and a platelet count of 9 × 10⁹/L requires emergency laparotomy for bowel perforation within 2 hours. Which statement regarding platelet transfusion is most accurate?

Give 1 adult therapeutic dose immediately before skin incision and repeat intraoperatively as needed, targeting a count >100 × 10⁹/L
Platelet transfusion is absolutely contraindicated in ITP regardless of clinical context
Platelet transfusion will be largely ineffective due to rapid antibody-mediated destruction; IV immunoglobulin with or without corticosteroids is the preferred strategy (Correct answer)
Transfuse 2 adult therapeutic doses of platelets now to achieve a pre-operative count >50 × 10⁹/L

Correct answer: Platelet transfusion will be largely ineffective due to rapid antibody-mediated destruction; IV immunoglobulin with or without corticosteroids is the preferred strategy

In ITP, circulating anti-platelet IgG autoantibodies (targeting GPIIb/IIIa or GPIb/IX) cause rapid reticuloendothelial destruction of transfused platelets, typically within minutes to 1–2 hours. Transfusion is therefore largely ineffective when given hours before surgery. IVIg (1 g/kg/day for 1–2 days) saturates Fc receptors and can raise platelet counts within 24–48 hours; high-dose corticosteroids offer a similar effect over 2–5 days. If surgery cannot be delayed and platelet transfusion is deemed necessary, it should be given as a large dose (2–3 adult doses) immediately at the time of skin incision — not hours beforehand. It is not absolutely contraindicated but should not be the sole strategy.

Question 121: A study reports a 95% confidence interval for the mean difference in arterial pressure between two groups as −2 to +8 mmHg. What is the most appropriate interpretation?

The result is statistically significant at p < 0.05
The result is not statistically significant at p < 0.05 because the interval includes zero (Correct answer)
A larger sample would guarantee significance
The treatment definitely has no effect

Correct answer: The result is not statistically significant at p < 0.05 because the interval includes zero

A 95% CI that crosses zero (the null value for a difference) means we cannot exclude no effect, which corresponds to p > 0.05 — the result is not statistically significant. Note this does not prove the treatment has no effect; the study may simply be underpowered. Clinical significance (is a difference of 8 mmHg important?) is a separate question from statistical significance.

EDAIC Part I — European Diploma in Anaesthesiology and Intensive Care

The EDAIC Part I exam assesses knowledge of basic sciences and clinical anaesthesiology through two papers of 60 multiple true/false questions each, covering pharmacology, physiology, anatomy, physics, and clinical anaesthesia.

120

Questions

180 min

Time Limit

60%

To Pass

Checking for saved progress...

Exam Rules

You can skip questions and return to them later
Flag questions for review before submitting
No feedback shown until you submit the entire exam
Unanswered questions count as wrong — answer everything
10 pretest questions are mixed in and don't affect your score
Timer auto-submits when time runs out
Your progress is auto-saved every 30 seconds

These practice questions were written with AI tools. They are not real exam questions. Exam facts are checked against the official sources listed below. Not reviewed by a subject-matter expert. Editorial policy

Sources & references

Exam facts on this page (fees, format, dates, passing scores) are checked against these official sources; the date is our last check. Editorial policy

esaic.org — Eligibility, passing score, time limit, test delivery, score release, exam dates · verified Oct 2026