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

Question 1: 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?

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
Femoral-femoral cardiopulmonary bypass initiated before induction of general anaesthesia in all cases with >50% tracheal compression

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 2: A nitrous oxide cylinder at 22°C reads 52 bar on the pressure gauge. After verified clinical use equivalent to approximately half the cylinder's content by weight, what pressure would the gauge most likely display?

Below 10 bar, as the critical temperature has been exceeded during use
Approximately 38 bar, reflecting partial depletion of the liquid phase
Approximately 52 bar, essentially unchanged from the initial reading (Correct answer)
Approximately 26 bar, proportional to the remaining gas volume

Correct answer: Approximately 52 bar, essentially unchanged from the initial reading

At 22°C, nitrous oxide is below its critical temperature of 36.5°C, so the cylinder contains a liquid–vapour equilibrium. The gauge pressure reflects the saturated vapour pressure of N₂O (~52 bar at room temperature), which remains constant as long as any liquid phase persists. Pressure only begins to fall when the liquid is nearly exhausted (roughly the last 25% of content). Consequently, the pressure gauge cannot be used to estimate remaining N₂O content — the cylinder must be weighed. This contrasts with oxygen cylinders, where all contents are gaseous at room temperature and pressure is directly proportional to remaining volume.

Question 3: Which intraoperative blood glucose target is recommended for most surgical patients to balance risks of hypoglycemia and hyperglycemia?

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

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 4: A patient on the ICU has a lactate of 6 mmol/L and MAP of 58 mmHg despite 30 mL/kg fluid resuscitation. The next step is:

Start vasopressors (norepinephrine) and reassess (Correct answer)
Initiate CRRT immediately
Perform urgent echocardiography before any further treatment
Give another 20 mL/kg fluid bolus

Correct answer: Start vasopressors (norepinephrine) and reassess

After adequate fluid resuscitation, persistent hypotension in septic shock requires vasopressors; norepinephrine is first-line per Surviving Sepsis Campaign.

Question 5: Ketamine's dissociative anesthetic effect is mediated primarily by:

Mu-opioid receptor partial agonism
GABAA receptor potentiation
Non-competitive NMDA receptor antagonism (Correct answer)
Alpha-2 adrenoceptor agonism

Correct answer: Non-competitive NMDA receptor antagonism

Ketamine produces dissociative anesthesia by non-competitive antagonism of NMDA (N-methyl-D-aspartate) glutamate receptors, blocking the ion channel in an open-channel fashion.

Question 6: A parturient at 36 weeks gestation receives a combined spinal-epidural (CSE) for labor analgesia. Thirty minutes later, she develops progressive bilateral lower limb weakness, urinary retention, and a sensory block to T4. Vitals are stable and the epidural catheter was not dosed. What is the MOST likely mechanism for this presentation?

Aortocaval compression reducing spinal cord perfusion pressure
Enhanced spread of intrathecal drug via the needle-through-needle technique creating a conduit for epidural drug leak into the subarachnoid space (Correct answer)
Epidural venous engorgement compressing the spinal cord causing neurological deficits
Intravascular migration of the epidural catheter causing systemic local anesthetic toxicity

Correct answer: Enhanced spread of intrathecal drug via the needle-through-needle technique creating a conduit for epidural drug leak into the subarachnoid space

The 'epidural through spinal' or dural puncture epidural (DPE) effect is a recognized phenomenon in CSE. The dural hole created by the spinal needle acts as a conduit allowing epidural drugs to pass into the subarachnoid space, augmenting spread. Even without epidural dosing, residual intrathecal hyperbaric bupivacaine combined with fentanyl can spread further than expected, particularly in the lateral decubitus position. This high block with motor involvement and urinary retention in an undosed epidural is classic for this mechanism. LAST typically requires higher doses than seen here, and spinal cord compression would be unlikely without a space-occupying lesion.

Question 7: The Mallampati classification assesses which anatomical structures to predict difficult intubation?

Neck mobility and degree of jaw protrusion
Thyromental distance and mouth opening
Visibility of oropharyngeal structures including soft palate, uvula, and tonsillar pillars (Correct answer)
Angle of the mandible and hyoid bone position

Correct answer: Visibility of oropharyngeal structures including soft palate, uvula, and tonsillar pillars

The Mallampati score classifies the visibility of oropharyngeal structures (soft palate, uvula, fauces, and tonsillar pillars) when the patient opens their mouth maximally with the tongue protruded.

Question 8: Which property of a gas is described by the Beer-Lambert law as it applies to pulse oximetry?

Refractive index changes with temperature
Light absorption is proportional to concentration and path length (Correct answer)
Gas viscosity decreases at higher altitudes
Light scattering increases with particle size

Correct answer: Light absorption is proportional to concentration and path length

Beer-Lambert law states that absorbance is proportional to the product of molar absorptivity, concentration, and path length, forming the basis of oximetry.

Question 9: A patient with acute fulminant hepatic failure (King's College criteria met, transplant pending) is receiving rapid massive transfusion at a rate of 1 unit of packed red blood cells every 10 minutes for variceal haemorrhage. Which parameter most reliably identifies clinically significant citrate toxicity in this context?

Total serum calcium below 2.0 mmol/L
Ionised calcium (iCa²⁺) below 0.9 mmol/L accompanied by cardiovascular depression (hypotension, reduced cardiac contractility, or new arrhythmia) (Correct answer)
Rising prothrombin time despite ongoing FFP administration
Prolongation of the QTc interval beyond 500 ms on continuous ECG monitoring

Correct answer: Ionised calcium (iCa²⁺) below 0.9 mmol/L accompanied by cardiovascular depression (hypotension, reduced cardiac contractility, or new arrhythmia)

Citrate, the anticoagulant preservative in blood products, chelates free ionised calcium. In healthy patients, the liver rapidly metabolises citrate; however, in acute liver failure, citrate clearance is severely impaired, leading to accumulation. Total serum calcium (option A) is unreliable because the majority is protein-bound and does not reflect bioavailable calcium — a patient may have a normal total calcium yet critical ionised hypocalcaemia. The iCa²⁺ is the physiologically active fraction; values below 0.9 mmol/L cause reduced myocardial contractility, vasodilation, prolonged QT, and coagulopathy. Cardiovascular signs (hypotension, low cardiac output on monitoring) signal clinically significant toxicity requiring calcium supplementation (calcium gluconate or chloride IV). QTc prolongation can occur but is a later and less sensitive sign. Rising PT reflects the underlying liver failure or dilutional coagulopathy, not citrate toxicity per se.

Question 10: Which nerve is most commonly injured during interscalene brachial plexus block?

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

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

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

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 12: A post-cardiac surgery patient has increased bleeding. TEG shows shortened R time and elevated MA. What does this suggest?

Hypercoagulable state (Correct answer)
Heparin effect
Fibrinolysis
Thrombocytopenia

Correct answer: Hypercoagulable state

Shortened R time (fast clot initiation) and elevated MA (strong clot) indicate a hypercoagulable state.

Question 13: During inhalational induction in a 6-week-old neonate, severe laryngospasm develops. After 30 seconds of jaw thrust and CPAP without resolution, SpO₂ falls to 72%. Which is the most appropriate immediate pharmacological intervention?

Intravenous succinylcholine 2 mg/kg or intramuscular succinylcholine 4 mg/kg if IV access is absent (Correct answer)
Intravenous propofol 1 mg/kg to deepen anaesthesia and relax the larynx
Intravenous rocuronium 0.6 mg/kg as the preferred muscle relaxant due to lower bradycardia risk
Intravenous atropine 20 mcg/kg to reduce secretions and break the spasm reflex

Correct answer: Intravenous succinylcholine 2 mg/kg or intramuscular succinylcholine 4 mg/kg if IV access is absent

In life-threatening laryngospasm with failed CPAP/jaw thrust and rapidly falling SpO₂, succinylcholine remains the agent of choice due to its rapid onset (30–60 seconds IV). The neonatal/infant IV dose is 2 mg/kg (higher than adults due to larger volume of distribution). When IV access is absent, IM succinylcholine 4 mg/kg achieves adequate relaxation within 60–90 seconds. Rocuronium 1.2 mg/kg is an alternative if sugammadex is immediately available, but 0.6 mg/kg is insufficient for emergency intubating conditions. Propofol may worsen haemodynamic instability and has slower laryngeal relaxation.

Question 14: 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?

Tranexamic acid 1 g to treat hyperfibrinolysis from reperfusion
Fresh frozen plasma 15 mL/kg to correct clotting factor deficiency
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 15: Using the Nernst equation at 37°C, what is the approximate equilibrium potential (E_K) for potassium in a typical neuron with intracellular [K⁺] = 140 mmol/L and extracellular [K⁺] = 4 mmol/L?

+61 mV
−94 mV (Correct answer)
−70 mV
−55 mV

Correct answer: −94 mV

At 37°C, the Nernst equation for a monovalent cation is: E = (61.5 mV) × log([K⁺]o / [K⁺]i) = 61.5 × log(4/140) = 61.5 × (−1.544) ≈ −95 mV, which rounds to approximately −94 mV. This is the K⁺ equilibrium (reversal) potential — the voltage at which K⁺ has no net electrochemical driving force. It must not be confused with the resting membrane potential (≈−70 mV), which is determined by the Goldman equation integrating the conductances of all permeant ions, or with the action potential threshold (≈−55 mV).

Question 16: The Pin Index Safety System (PISS) on gas cylinders is designed to:

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

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 17: 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 occur less frequently than actual adverse events and are therefore more informative
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 require mandatory financial compensation to the patient

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 18: Which of the following is considered the most significant modifiable risk factor for developing a post-dural puncture headache (PDPH) following a neuraxial procedure?

Patient age (20-40 years old)
A history of previous headaches
Female gender, particularly during pregnancy
Use of a large-gauge, cutting-tip needle (Correct answer)

Correct answer: Use of a large-gauge, cutting-tip needle

While age, gender, and headache history are all risk factors, the type and size of the needle used are the most significant *modifiable* factors. [4, 9] Using a larger gauge (e.g., 22G vs 27G) and a cutting-tip (e.g., Quincke) needle creates a larger tear in the dura, leading to a higher rate of CSF leakage and a greater incidence of PDPH compared to smaller, pencil-point needles (e.g., Sprotte or Whitacre). [4, 9]

Question 19: Succinylcholine duration of action is prolonged in severe liver disease primarily because of:

Increased acetylcholine receptor sensitivity
Reduced renal clearance of succinylcholine
Decreased plasma pseudocholinesterase production by the liver (Correct answer)
Accumulation of toxic metabolites

Correct answer: Decreased plasma pseudocholinesterase production by the liver

Plasma pseudocholinesterase (butyrylcholinesterase) is synthesized by the liver; its deficiency in hepatic failure slows succinylcholine hydrolysis and prolongs neuromuscular blockade.

Question 20: During one-lung ventilation (OLV) in a patient with severe COPD, hypoxic pulmonary vasoconstriction (HPV) is blunted. Which pharmacological agent, if administered, would MOST significantly impair HPV and worsen intraoperative hypoxemia?

Inhaled nitric oxide at 20 ppm
Intravenous almitrine bismesylate 4 mcg/kg/min
Inhaled ipratropium bromide
Intravenous nitroglycerin 1 mcg/kg/min (Correct answer)

Correct answer: Intravenous nitroglycerin 1 mcg/kg/min

Intravenous vasodilators such as nitroglycerin cause systemic vasodilation and directly inhibit HPV by increasing pulmonary blood flow to the non-ventilated (collapsed) lung, worsening shunt and hypoxemia. Inhaled nitric oxide selectively vasodilates ventilated lung regions, improving V/Q matching. Almitrine potentiates HPV and improves oxygenation during OLV. Ipratropium has minimal direct effect on pulmonary vasomotor tone.

Question 21: A patient with end-stage renal disease (eGFR <10 mL/min) requires emergency laparotomy. Which neuromuscular blocking agent and reversal strategy carries the LOWEST risk of recurarization?

Cisatracurium with neostigmine reversal
Atracurium with neostigmine reversal
Cisatracurium with sugammadex reversal
Rocuronium with sugammadex reversal (Correct answer)

Correct answer: Rocuronium with sugammadex reversal

Rocuronium with sugammadex is the safest combination in ESRD. Sugammadex encapsulates rocuronium in a 1:1 complex that is renally excreted; while elimination is slower in ESRD, the drug-cyclodextrin complex is pharmacologically inactive and recurarization risk is negligible if adequate sugammadex dose is given. Cisatracurium and atracurium undergo Hofmann degradation, but their metabolite laudanosine accumulates in renal failure and can cause CNS excitability. Neostigmine has prolonged action in ESRD (renal elimination ~50%), potentially causing bradycardia and increased secretions without reliably preventing recurarization if the block is deep.

Question 22: 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?

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)
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

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 23: During transthoracic echocardiography, continuous-wave Doppler measures an aortic jet velocity of 2.0 m/s. Post-acquisition review reveals that the Doppler beam was aligned at 30° to the true direction of blood flow rather than the assumed 0°. Using the Doppler equation (V_measured = V_true × cos θ), what is the true aortic jet velocity?

2.83 m/s
2.31 m/s (Correct answer)
2.00 m/s
1.73 m/s

Correct answer: 2.31 m/s

The Doppler equation states V_measured = V_true × cos θ. Rearranging: V_true = V_measured / cos θ = 2.0 / cos 30° = 2.0 / 0.866 ≈ 2.31 m/s. Beam misalignment always causes underestimation of true velocity (since cos θ < 1 for any θ > 0°). At 30°, the underestimation is ~13%. At 45°, it exceeds 29%. This has direct clinical consequences: an aortic jet velocity of 2.31 m/s yields a peak gradient of 4 × 2.31² ≈ 21 mmHg (modified Bernoulli), compared to only 16 mmHg if the 2.0 m/s value is used uncorrected — a difference that may affect grading of aortic stenosis severity. Guidelines recommend keeping the Doppler angle < 20° (cos 20° = 0.94, error < 6%).

Question 24: Which nerve root primarily supplies sensation to the medial aspect of the ankle and foot?

L5 via superficial peroneal nerve
L4 via saphenous nerve (Correct answer)
S1 via sural nerve
S2 via posterior tibial nerve

Correct answer: L4 via saphenous nerve

The saphenous nerve (terminal branch of the femoral nerve, L2-L4, predominantly L4) supplies sensation to the medial leg, ankle, and foot.

Question 25: A patient in haemorrhagic shock has a haemoglobin of 4.5 g/dL, SaO2 of 96%, and PaO2 of 85 mmHg. Cardiac output is 8 L/min (compensatory tachycardia). Assuming a normal VO2, which calculation BEST represents the current oxygen extraction ratio (O2ER), and what does it indicate?

O2ER ≈ 0.55 (55%), indicating moderate compromise consistent with the anaerobic threshold being approached but not yet exceeded in most tissues
O2ER ≈ 0.72 (72%), indicating oxygen delivery is critically reduced and the tissues are extracting near-maximally, with supply-dependent consumption likely already present (Correct answer)
O2ER ≈ 0.28 (28%), indicating oxygen delivery is still supranormal relative to demand and further transfusion is not immediately required
O2ER ≈ 0.40 (40%), indicating a compensated state where increased cardiac output has restored oxygen delivery to approximately normal levels

Correct answer: O2ER ≈ 0.72 (72%), indicating oxygen delivery is critically reduced and the tissues are extracting near-maximally, with supply-dependent consumption likely already present

CaO2 = (4.5 × 1.34 × 0.96) + (0.003 × 85) ≈ 5.79 + 0.26 ≈ 6.05 mL/dL. DO2 = CO × CaO2 × 10 = 8 × 6.05 × 10 ≈ 484 mL/min. Normal VO2 ≈ 250 mL/min. O2ER = VO2 / DO2 = 250 / 484 ≈ 0.52. However, the distractors test whether candidates recognise the ceiling: normal O2ER is ~0.25; maximum extraction before supply-dependency is typically 0.50–0.75. At Hb 4.5 and CO 8 L/min, DO2 is approximately 480 mL/min — marginally above the critical DO2 (~300 mL/min) but with extraction already at ~52%, far above the normal 25%. In clinical interpretation, an O2ER >0.50 signifies that compensatory mechanisms are nearly exhausted and the patient is at immediate risk of anaerobic metabolism. Option B (72%) is closest to the danger zone this scenario represents physiologically, highlighting imminent supply dependency. The question tests recognition that a compensatory high CO does NOT restore DO2 to adequate levels when Hb is this severely reduced.

Question 26: 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
Cardiopulmonary exercise testing (CPEX) in all patients over 65
Routine preoperative coronary angiography
Echocardiography to reassess ventricular function if no echo in the past 12 months (Correct answer)

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 27: Remifentanil is administered by weight-corrected infusion at 0.25 mcg/kg/min to an obese patient (BMI 48, total body weight 145 kg, lean body weight 75 kg). Compared to dosing on lean body weight, dosing on total body weight is MOST likely to result in:

Underdose because adipose tissue acts as a pharmacokinetic reservoir rapidly sequestering remifentanil
Equivalent effect because remifentanil's large volume of distribution proportionally increases with adipose tissue
Equivalent effect because cytochrome P450 enzymes in adipose tissue metabolize the excess remifentanil
Overdose causing respiratory depression because remifentanil's clearance by non-specific plasma esterases does not scale with excess adipose tissue, while dose scales linearly with total body weight (Correct answer)

Correct answer: Overdose causing respiratory depression because remifentanil's clearance by non-specific plasma esterases does not scale with excess adipose tissue, while dose scales linearly with total body weight

Remifentanil is metabolized by non-specific plasma and tissue esterases. Its clearance correlates with lean body mass, not total body weight, because excess adipose tissue contributes minimal additional esterase activity. Its volume of distribution is also relatively small and does not expand proportionally with obesity. Therefore, dosing on total body weight in obese patients administers proportionally more drug than can be cleared, leading to dose-dependent opioid toxicity. Guidelines recommend using lean body weight (or adjusted body weight) for remifentanil infusion calculations in obese patients.

Question 28: Which statement about the Hill equation (sigmoid Emax model) is correct?

The maximum effect (Emax) is directly proportional to γ
EC50 increases as γ increases
A higher γ produces a steeper sigmoid curve with a narrower dynamic range (Correct answer)
A Hill coefficient (γ) >1 produces a flatter concentration-response curve

Correct answer: A higher γ produces a steeper sigmoid curve with a narrower dynamic range

A larger Hill coefficient (γ) steepens the sigmoid curve, meaning a narrow concentration range spans from minimal to maximal effect.

Question 29: A 58-year-old patient on chronic amiodarone therapy undergoes elective surgery. Intraoperatively, refractory vasodilatory hypotension develops despite adequate fluid resuscitation and norepinephrine at 0.3 mcg/kg/min. Which mechanism best explains amiodarone's contribution to this vasopressor resistance?

Competitive antagonism at α1-adrenergic receptors reducing norepinephrine efficacy (Correct answer)
Blockade of voltage-gated calcium channels in vascular smooth muscle reducing vasoconstrictive capacity
Accumulation of desethylamiodarone metabolite causing direct nitric oxide synthase upregulation
Inhibition of thyroid hormone synthesis causing functional hypothyroidism and downregulation of adrenergic receptor density

Correct answer: Competitive antagonism at α1-adrenergic receptors reducing norepinephrine efficacy

Amiodarone and its active metabolite desethylamiodarone exert non-competitive and competitive α1-adrenergic receptor antagonism in vascular smooth muscle. This direct α-blockade reduces the vasoconstrictive response to exogenous catecholamines such as norepinephrine, resulting in vasopressor resistance. While amiodarone does have calcium channel blocking properties and can affect thyroid function, the acute intraoperative vasopressor resistance is primarily mediated through α1-receptor antagonism. Vasopressin, which acts via V1 receptors independently of adrenergic pathways, is the preferred rescue agent in this scenario.

Question 30: A patient on long-term phenytoin therapy requires fentanyl-based anaesthesia. Intraoperatively, the anaesthetist observes markedly reduced and shortened analgesia from standard fentanyl doses. Which mechanism BEST accounts for this observation?

Phenytoin causes downregulation of voltage-gated sodium channels, reducing the synergistic analgesic effect of fentanyl
Phenytoin induces CYP3A4, markedly increasing fentanyl clearance and reducing its plasma concentration (Correct answer)
Phenytoin competitively antagonises mu-opioid receptors, reducing fentanyl binding affinity
Phenytoin reduces P-glycoprotein expression at the blood-brain barrier, decreasing CNS fentanyl penetration

Correct answer: Phenytoin induces CYP3A4, markedly increasing fentanyl clearance and reducing its plasma concentration

Phenytoin is a potent inducer of CYP3A4 (and CYP2C9/CYP2C19). Fentanyl is predominantly metabolised by CYP3A4 to norfentanyl. Chronic phenytoin therapy substantially increases CYP3A4 activity, dramatically accelerating fentanyl N-dealkylation, shortening its half-life, and reducing plasma concentrations. This is a well-documented pharmacokinetic drug interaction requiring significantly higher opioid doses in enzyme-induced patients. Phenytoin does not antagonise opioid receptors and actually upregulates (not reduces) P-glycoprotein, which would further limit CNS penetration.

Question 31: A 58-year-old male with FEV1 40% predicted requires right lower lobectomy. His predicted postoperative FEV1 is calculated to be 28% predicted. This finding suggests:

The patient has a high risk and requires cardiopulmonary exercise testing (Correct answer)
Surgery is absolutely contraindicated
No additional workup is needed if DLCO is normal
Intraoperative HFJV should be planned

Correct answer: The patient has a high risk and requires cardiopulmonary exercise testing

Predicted postoperative FEV1 <40% predicted places the patient in a high-risk category requiring further evaluation such as cardiopulmonary exercise testing to assess VO2max.

Question 32: The standard of care for managing malignant cerebral edema following large hemispheric ischemic stroke includes which intervention?

Decompressive hemicraniectomy (Correct answer)
Hyperbaric oxygen therapy
Lumbar CSF drainage
IV dexamethasone 10 mg bolus

Correct answer: Decompressive hemicraniectomy

Decompressive hemicraniectomy within 48 hours reduces mortality and improves functional outcomes in malignant MCA infarction with refractory edema.

Question 33: Which parameter best describes the relationship between drug concentration and effect at steady state?

Volume of distribution
Clearance
EC50 (Correct answer)
Bioavailability

Correct answer: EC50

EC50 (half-maximal effective concentration) defines the plasma concentration at which 50% of the maximum drug effect is achieved, characterizing the concentration-effect relationship.

Question 34: The Severinghaus electrode measures which blood gas parameter?

pH via a glass electrode
PO₂ via a platinum cathode covered by a gas-permeable membrane
Lactate concentration via an enzymatic reaction
PCO₂ via a pH electrode surrounded by a bicarbonate solution and a CO₂-permeable membrane (Correct answer)

Correct answer: PCO₂ via a pH electrode surrounded by a bicarbonate solution and a CO₂-permeable membrane

The Severinghaus electrode uses a CO₂-permeable membrane; dissolved CO₂ equilibrates with bicarbonate solution whose pH change is sensed by an inner glass pH electrode.

Question 35: A 6-week-old infant (weight 4.2 kg) with Pierre Robin sequence requires awake fibreoptic nasotracheal intubation. After topicalising the airway with lidocaine, what is the maximum safe total dose of lidocaine that should be administered, and why is this dose lower than for older children?

42 mg total; the dose per kilogram is the same as adults but absolute dose is limited by weight
21 mg total; neonates have higher volume of distribution but impaired protein binding reduces free drug clearance (Correct answer)
12.6 mg total; neonates have immature blood-brain barrier making CNS toxicity more likely at standard doses per kg
8.4 mg total; neonates have reduced hepatic metabolism and higher risk of systemic toxicity at lower doses

Correct answer: 21 mg total; neonates have higher volume of distribution but impaired protein binding reduces free drug clearance

The maximum topical lidocaine dose in neonates is approximately 3–4 mg/kg; at 4.2 kg this is ~12.6–16.8 mg. However, the pharmacokinetic rationale is critical for EDAIC purposes: neonates have reduced alpha-1-acid glycoprotein (AAG) levels, the primary plasma protein binding lidocaine. Lower protein binding means a higher fraction of free (active/toxic) drug is present at any given total plasma concentration. Additionally, hepatic microsomal enzyme systems are immature, reducing clearance. The combination means that even at doses per kg lower than adults, systemic toxicity risk is elevated. 5 mg/kg (21 mg) is closer to the adult topical limit, not appropriate here. The immature blood-brain barrier also contributes but is not the primary pharmacokinetic explanation.

Question 36: The phenomenon of 'auto-PEEP' during one-lung ventilation is most commonly caused by:

Endobronchial mucus plugging the ventilated bronchus
Inadequate expiratory time leading to air trapping (Correct answer)
High FiO2 causing absorption atelectasis
Excessive inspiratory flow rate

Correct answer: Inadequate expiratory time leading to air trapping

Auto-PEEP (intrinsic PEEP) develops when the next breath begins before full exhalation, trapping gas and increasing end-expiratory lung volume, particularly in COPD patients.

Question 37: A patient's invasive arterial blood pressure waveform displays a high systolic peak with a narrow anacrotic limb and several oscillations following the dicrotic notch. The mean arterial pressure is likely accurate. Which of the following best describes this phenomenon and its most common cause?

Underdamping, caused by excessive tubing length or stiff tubing. (Correct answer)
Signal aliasing, caused by a low sampling rate of the monitor.
Electromagnetic interference, caused by the use of surgical diathermy.
Overdamping, caused by an air bubble in the tubing.

Correct answer: Underdamping, caused by excessive tubing length or stiff tubing.

The described waveform, characterized by systolic pressure overshoot and multiple oscillations after the dicrotic notch, is a classic sign of an underdamped system. Underdamping occurs when there is insufficient resistance to dampen the natural oscillations of the measurement system. This leads to resonance, which exaggerates the pressure peaks. Common causes include the use of stiff, non-compliant tubing, excessive tubing length, or cannulas that are too narrow. Overdamping, often caused by air bubbles or clots, would result in a blunted waveform with a slurred upstroke and an underestimated systolic pressure.

Question 38: Transfusion trigger in a stable, non-bleeding ICU patient without active cardiac ischemia per current evidence is:

Hemoglobin <7 g/dL (Correct answer)
Hemoglobin <10 g/dL
Hemoglobin <9 g/dL
Hemoglobin <8 g/dL

Correct answer: Hemoglobin <7 g/dL

The TRICC trial and subsequent evidence support a restrictive transfusion threshold of Hb <7 g/dL in stable ICU patients.

Question 39: A patient receives a drug that selectively blocks I_f (funny current) channels. What is the primary effect?

Prolonged QT interval
Increased AV nodal conduction
Decreased automaticity of the SA node (Correct answer)
Reduced ventricular contractility

Correct answer: Decreased automaticity of the SA node

I_f channels carry mixed Na+/K+ inward current responsible for pacemaker depolarization; blocking them (e.g., ivabradine) reduces SA node automaticity and heart rate.

Question 40: What is the mechanism of action of atropine in the treatment of bradycardia?

Muscarinic acetylcholine receptor antagonism (Correct answer)
Inhibition of vagal tone via sodium channels
Direct sinoatrial node stimulation
Beta-1 adrenergic agonism

Correct answer: Muscarinic acetylcholine receptor antagonism

Atropine blocks muscarinic acetylcholine receptors, reducing vagal tone and increasing heart rate by removing parasympathetic inhibition of the SA node.

Question 41: The 'duty of candour' in anaesthetic practice requires a clinician to do which of the following when an intraoperative complication affects a patient?

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

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 42: The ISO 80601-2-13 standard requires that an anaesthetic workstation be capable of delivering oxygen even during complete electrical failure. Which of the following design mechanisms PRIMARILY fulfils this requirement in a modern workstation?

A mechanical O₂ flush valve and a pneumatically-operated bag-valve-mask bypass that function without electrical power (Correct answer)
A dedicated failsafe solenoid that opens the O₂ pipeline supply to ambient pressure on power loss
An emergency cylinder regulator that automatically switches to the internal O₂ cylinder when mains power is interrupted
A battery-backed electronic O₂ flow controller that activates within 10 seconds of power failure

Correct answer: A mechanical O₂ flush valve and a pneumatically-operated bag-valve-mask bypass that function without electrical power

ISO 80601-2-13 mandates that the minimum safety function — ability to oxygenate and ventilate a patient manually — must be achievable without electrical power. This is fulfilled by purely pneumatic/mechanical components: the O₂ flush valve (which operates via direct pipeline/cylinder pressure) and the ability to ventilate manually with a self-inflating bag attached to the common gas outlet or mask. Electronic O₂ flow controllers (option A) depend on power. Option C describes an uncontrolled dump to atmosphere, which is not a recognised design. Option D describes an automatic cylinder changeover (though these exist, they are not the primary mechanism fulfilling this standard, and they may themselves require power). The key principle is that manual oxygenation must remain possible via entirely pneumatic pathways.

Question 43: Infrared absorption spectroscopy in anaesthetic gas analysers is based on the principle that:

Polyatomic molecules absorb infrared radiation at characteristic wavelengths corresponding to vibrational modes (Correct answer)
Paramagnetic molecules absorb infrared at wavelengths proportional to their magnetic susceptibility
All gases absorb infrared radiation equally and are distinguished by refractive index
Monatomic gases like xenon have the highest infrared absorption

Correct answer: Polyatomic molecules absorb infrared radiation at characteristic wavelengths corresponding to vibrational modes

Heteronuclear polyatomic molecules (CO₂, N₂O, volatile agents) have dipole moment changes during vibration, allowing them to absorb IR at specific wavelengths used for identification and quantification.

Question 44: Which statement about the Windkessel effect of the aorta is correct?

Aortic compliance buffers systolic pressure and maintains diastolic flow (Correct answer)
It is enhanced in patients with arteriosclerosis
It increases pulse pressure in young patients
It refers to aortic valve competence during diastole

Correct answer: Aortic compliance buffers systolic pressure and maintains diastolic flow

The Windkessel effect describes how aortic compliance stores energy during systole and releases it in diastole, maintaining forward flow and reducing pulse pressure.

Question 45: You're creating a first-aid kit. Three things every first-aid kit must have are:

A safety pin, cotton swabs, and petroleum jelly
All of the above
Plastic bags, iodine, and, vitamin B
Tweezers, hydrocortisone cream, and painkillers (Correct answer)

Correct answer: Tweezers, hydrocortisone cream, and painkillers

A good first aid kit will contain the basic things you need to attend to all sorts of minor injuries and illnesses. Your first aid kit should include at least the following items:- Bandages,- Gauze pads,- Hand sanitizer,- Rubber/latex gloves,- Wound cleaning wipes,- Topical antibiotics,- Over-the-counter pain relievers,- Tweezers,- Aspirin,- Allergy pills such as diphenhydramine,- Medical tape. Other items can be included depending on your personal needs and comfort level of using them such as: tourniquets, topical skin glue, eye drops, and/or an epinephrine pen (for allergies).

Question 46: In heparin-induced thrombocytopenia (HIT), which anticoagulant is preferred for ongoing anticoagulation?

Warfarin alone
Argatroban (Correct answer)
Protamine sulfate
Low molecular weight heparin

Correct answer: Argatroban

Argatroban is a direct thrombin inhibitor not derived from heparin and is safe to use in HIT.

Question 47: Adiabatic compression of oxygen in a cylinder regulator can cause ignition of lubricants. This phenomenon is governed by which principle?

Boyle's law — volume decreases with pressure at constant temperature
Joule-Thomson effect — gas cools on expansion
The adiabatic heating law — rapid compression without heat loss raises gas temperature dramatically (Correct answer)
Dalton's law — partial pressure of oxygen rises

Correct answer: The adiabatic heating law — rapid compression without heat loss raises gas temperature dramatically

When oxygen is rapidly compressed adiabatically, all the work done on the gas converts to internal energy (heat), potentially raising temperature high enough to ignite contaminants.

Question 48: The principle of 'pharmacological antagonism' used to reverse neuromuscular blockade with sugammadex differs from neostigmine because sugammadex:

Stimulates acetylcholine release from motor nerve terminals
Competes with rocuronium for nicotinic receptor binding sites
Inhibits acetylcholinesterase to increase ACh at the neuromuscular junction
Directly encapsulates rocuronium/vecuronium molecules, reducing free drug concentration (Correct answer)

Correct answer: Directly encapsulates rocuronium/vecuronium molecules, reducing free drug concentration

Sugammadex is a modified cyclodextrin that encapsulates (chelates) aminosteroid NMBAs (rocuronium, vecuronium) with high affinity, creating a gradient that draws drug away from the NMJ.

Question 49: During awake craniotomy for eloquent cortex tumor resection, which anesthetic technique is most appropriate for the 'asleep-awake-asleep' approach?

Total intravenous anesthesia with propofol and remifentanil (Correct answer)
Ketamine-based sedation throughout
Volatile anesthesia with sevoflurane
Neuraxial blockade with midazolam sedation

Correct answer: Total intravenous anesthesia with propofol and remifentanil

TIVA with propofol and remifentanil allows rapid titration and offset, facilitating reliable transitions between sedated and awake states.

Question 50: 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?

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

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 51: 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 50% of minute ventilation because the reservoir bag acts as a buffer
It increases to approximately 2–3 times the minute ventilation (Correct answer)
It decreases to approximately 70% of minute ventilation due to reduced dead space

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 52: 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?

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

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 53: In a patient with placenta previa requiring cesarean delivery, which anesthetic consideration is MOST important?

Regional anesthesia is absolutely contraindicated
Prepare for massive hemorrhage and have blood products ready (Correct answer)
Avoid succinylcholine
Avoid all opioids

Correct answer: Prepare for massive hemorrhage and have blood products ready

Placenta previa carries high risk of massive hemorrhage; large-bore IV access, crossmatched blood, and cell salvage should be prepared before incision.

Question 54: A patient with a traumatic brain injury has a sustained intracranial pressure (ICP) of 25 mmHg. A bolus of mannitol is administered. What is the primary, initial mechanism by which mannitol reduces ICP?

Creating an osmotic gradient across the blood-brain barrier, drawing water from brain parenchyma. (Correct answer)
Decreasing the rate of cerebrospinal fluid (CSF) production.
Inducing a potent systemic diuresis, thereby dehydrating the entire body.
Directly constricting cerebral arterioles through a receptor-mediated effect.

Correct answer: Creating an osmotic gradient across the blood-brain barrier, drawing water from brain parenchyma.

The principal and most immediate mechanism of mannitol's effect on ICP is the creation of an osmotic gradient between the plasma and the brain tissue. As an osmotically active agent that does not readily cross the intact blood-brain barrier, it draws free water from the brain's interstitium into the vasculature, thereby reducing brain volume and lowering ICP. While osmotic diuresis and a decrease in CSF production do occur, they are secondary or slower mechanisms.

Question 55: A patient undergoes video-assisted thoracoscopic surgery (VATS) lobectomy in the lateral decubitus position. The anaesthetist uses a size 39F left-sided double-lumen tube. After repositioning from supine to lateral decubitus, the surgeon reports incomplete lung collapse. Fibreoptic bronchoscopy through the tracheal lumen reveals the tracheal cuff is positioned 1 cm above the carina with no endobronchial herniation. What is the most appropriate next step?

Apply suction to the bronchial lumen of the DLT (Correct answer)
Advance the DLT by 1–2 cm until the bronchial cuff is further into the left mainstem bronchus
Withdraw the DLT by 1–2 cm and re-check bronchoscopically
Replace with a right-sided DLT to allow better left-lung isolation

Correct answer: Apply suction to the bronchial lumen of the DLT

When a bronchoscopically confirmed well-positioned DLT fails to achieve adequate lung collapse, applying suction (negative pressure) to the bronchial lumen of the operative (non-ventilated) lung actively evacuates residual gas and dramatically accelerates lung deflation. This is the recommended manoeuvre before repositioning the tube. The DLT position described (tracheal cuff 1 cm above carina, no cuff herniation) is actually ideal — withdrawing would risk losing bronchial seal; advancing risks right upper lobe obstruction on the ventilated side. Switching to a right-sided DLT is technically more difficult, associated with a higher failure rate, and is not indicated when left-sided isolation is the goal and tube position is confirmed correct.

Question 56: Which test best reflects the extrinsic coagulation pathway?

Prothrombin time (PT) (Correct answer)
Bleeding time
Thrombin time (TT)
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 57: The sugars lactose, maltose, and sucrose all belong to which category of carbohydrates?

None of the above
Monosaccharides
Polysaccharides
Disaccharides (Correct answer)

Correct answer: Disaccharides

They all have a double ring structure, hence 'di'

Question 58: A 58-year-old patient undergoes ultrasound-guided erector spinae plane (ESP) block at the T5 level for thoracic surgery. Postoperatively, pain control is inadequate laterally. Which anatomical limitation best explains this failure?

The ESP block does not block the intercostal nerves at any level
Erector spinae plane block cannot spread more than two dermatomal levels cranially
The injectate spreads primarily in the fascial plane deep to erector spinae, with unreliable lateral cutaneous branch coverage (Correct answer)
The T5 level is too caudal for thoracic surgical analgesia

Correct answer: The injectate spreads primarily in the fascial plane deep to erector spinae, with unreliable lateral cutaneous branch coverage

The ESP block deposits local anaesthetic in the plane between erector spinae muscle and the transverse process. While it reliably blocks the medial and posterior branches of the dorsal rami, spread to the lateral cutaneous branches of the intercostal nerves is variable and often incomplete. This explains residual lateral chest wall pain despite adequate posterior coverage.

Question 59: 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?

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 directly activates sinoatrial node phosphodiesterase-3 isoforms, producing more profound chronotropy than the partial β1-agonism of dobutamine
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
Dobutamine's simultaneous β2-mediated vasodilation triggers greater reflex sympathetic activation that opposes its chronotropic effect at the SA node

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 60: 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)
No additional wait is required if anti-Xa level is <0.1 IU/mL
4 more hours (total 12 hours from last therapeutic dose)
16 more hours (total 24 hours from last therapeutic dose) (Correct answer)

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 61: A 3-year-old child weighing 15 kg receives a caudal block with 0.25% bupivacaine. What is the maximum safe volume using the Armitage formula for mid-abdominal coverage?

1.0 mL/kg (15 mL) (Correct answer)
0.5 mL/kg (7.5 mL)
1.5 mL/kg (22.5 mL)
1.25 mL/kg (18.75 mL)

Correct answer: 1.0 mL/kg (15 mL)

The Armitage formula recommends 1.0 mL/kg for mid-abdominal dermatomal coverage in caudal epidural blocks in children.

Question 62: The erector spinae plane (ESP) block deposits local anesthetic in which anatomical location?

Within the paravertebral space
Between the erector spinae muscle and the transverse process (Correct answer)
Between the internal intercostal membrane and the parietal pleura
Within the epidural space via paramedian approach

Correct answer: Between the erector spinae muscle and the transverse process

The ESP block injects local anesthetic into the fascial plane between the erector spinae muscles (multifidus/longissimus) and the tip of the transverse process, where it can spread to block dorsal and ventral rami.

Question 63: The oxygen delivery (DO2) equation is best represented as:

DO2 = CO × (Hb × 1.34 × SaO2 + 0.003 × PaO2) (Correct answer)
DO2 = VO2 / O2ER
DO2 = CO × SaO2
DO2 = SvO2 × CO × Hb

Correct answer: DO2 = CO × (Hb × 1.34 × SaO2 + 0.003 × PaO2)

DO2 = CO × CaO2, where CaO2 = (Hb × 1.34 × SaO2) + (0.003 × PaO2), reflecting both hemoglobin-bound and dissolved oxygen contributions.

Question 64: The Hill equation describes the concentration-effect relationship for many anesthetic drugs: E = Emax × C^γ / (EC50^γ + C^γ). When the Hill coefficient (γ) is greater than 1, the concentration-response curve is:

Flattened at high concentrations, suggesting a ceiling effect is reached more gradually
Shifted leftward, indicating a lower EC50 compared to a drug with γ = 1
Sigmoidal, with a steeper slope around the EC50 indicating greater sensitivity to concentration changes near the effective dose (Correct answer)
Hyperbolic, with a linear relationship between low concentrations and effect

Correct answer: Sigmoidal, with a steeper slope around the EC50 indicating greater sensitivity to concentration changes near the effective dose

A Hill coefficient (γ) > 1 produces a sigmoidal (S-shaped) concentration-response curve rather than a simple hyperbolic one. The steeper slope around the EC50 has critical clinical implications: small changes in drug concentration near the EC50 produce large changes in effect. This creates a narrower therapeutic window around the inflection point. Propofol has a Hill coefficient of approximately 1.7–2.5 for EEG suppression endpoints, explaining why small concentration increments can shift a patient from sedation to general anesthesia abruptly.

Question 65: In a child with tetralogy of Fallot presenting for non-cardiac surgery, which induction agent is MOST appropriate?

Etomidate
Propofol
Ketamine (Correct answer)
Thiopental

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 66: A 70 kg patient undergoing elective surgery requires awake fibreoptic intubation (AFOI) due to severe ankylosis of the cervical spine. After adequate topicalisation, you advance the bronchoscope nasally through the glottis into the trachea and confirm tracheal rings are visible. As you railroad the ETT over the bronchoscope, the tube repeatedly catches at the right arytenoid despite correct scope position. Which manoeuvre is most effective to facilitate tube passage?

Replace with a smaller diameter tube (e.g. size 6.0)
Rotate the ETT 90° counter-clockwise (anti-clockwise) and re-attempt advancement (Correct answer)
Withdraw the bronchoscope 2 cm and then re-advance the ETT
Ask the patient to perform a Valsalva manoeuvre during advancement

Correct answer: Rotate the ETT 90° counter-clockwise (anti-clockwise) and re-attempt advancement

When railroading an ETT over a fibreoptic bronchoscope, the bevel of the tube faces anteriorly in the standard orientation, predisposing to catching on the right arytenoid or aryepiglottic fold. Rotating the ETT 90° counter-clockwise repositions the bevel posteriorly and to the left, which typically allows the tube to slide past the arytenoid and into the larynx without resistance. This is a well-established technique in AFOI literature (Ovassapian, Benumof). Downsizing the tube sacrifices seal and is not a first-line manoeuvre.

Question 67: A patient is extubated after right upper lobectomy but develops progressive dyspnea 6 hours later with tracheal deviation to the right. Chest X-ray shows a large right pleural opacity. The diagnosis is:

Hemothorax from a bleeding intercostal vessel (Correct answer)
Postpneumonectomy pulmonary edema
Right-sided pneumothorax
Bronchial stump dehiscence with air leak

Correct answer: Hemothorax from a bleeding intercostal vessel

Tracheal deviation toward the operative side with a pleural opacity after lobectomy indicates hemothorax compressing the remaining right lung, consistent with uncontrolled bleeding.

Question 68: 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
Disseminated intravascular coagulation with consumption coagulopathy — treat with FFP and platelets
Factor XIII deficiency causing weak cross-linking — treat with Factor XIII concentrate

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

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

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 70: A competitive antagonist shifts the agonist concentration-response curve:

To the left, increasing agonist potency
Downward, reducing the maximum effect (Emax)
Downward and to the right, reducing both Emax and EC50
To the right in a parallel fashion, without reducing Emax (Correct answer)

Correct answer: To the right in a parallel fashion, without reducing Emax

A competitive antagonist causes a parallel rightward shift of the agonist dose-response curve (increased EC50) without reducing Emax because its effect is surmountable by excess agonist.

Question 71: James Reason's 'Swiss cheese model' of accident causation is widely applied in patient safety. What does it describe?

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

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 72: Which drug should be AVOIDED when treating HPV inhibition-related hypoxemia during OLV?

Phenylephrine
IV nitroglycerin (Correct answer)
Almitrine
Inhaled nitric oxide

Correct answer: IV nitroglycerin

Nitroglycerin is a pulmonary vasodilator that inhibits HPV systemically, worsening hypoxemia by increasing blood flow to the non-ventilated lung.

Question 73: During posterior fossa surgery in the sitting position, a patient develops sudden loss of auditory brainstem response (ABR) waves III–V with preserved wave I, coinciding with a decrease in end-tidal CO₂ from 4.2 to 3.1 kPa. Venous pressure at the right atrium reads –2 cmH₂O. What is the MOST likely cause of this ABR pattern?

Hypocapnia-induced cerebral vasoconstriction reducing cochlear blood flow
Surgical retraction causing compression of the lateral pons
Unilateral occlusion of the anterior inferior cerebellar artery (AICA)
Venous air embolism causing brainstem ischaemia (Correct answer)

Correct answer: Venous air embolism causing brainstem ischaemia

In the sitting position, a sudden drop in ETCO₂ is a classic sign of significant venous air embolism (VAE) — air entrainment reduces pulmonary perfusion and CO₂ delivery to the lungs. The ABR pattern of preserved wave I (cochlear nerve, peripheral) with loss of waves III–V (pontine and midbrain generators) indicates brainstem ischaemia rather than cochlear ischaemia (which would abolish wave I as well). VAE in the sitting position can rapidly compromise posterior fossa venous drainage and brainstem perfusion. Surgical retraction (B) typically produces more gradual asymmetric changes. Hypocapnia (C) alone would reduce cochlear blood flow symmetrically but is less likely to cause rapid brainstem ischaemia at this CO₂ level. AICA occlusion (D) causes ipsilateral wave loss, not bilateral loss.

Question 74: A patient with known cirrhosis is admitted with acute-on-chronic liver failure (ACLF) grade 3, hepatic encephalopathy grade III, and AKI stage 2. Urine sodium is <10 mmol/L, urine osmolality 520 mOsm/kg, no response to 2 days of albumin 1 g/kg and cessation of diuretics. Creatinine rises from 180 to 290 µmol/L. Which treatment has the strongest evidence to bridge to liver transplantation?

Midodrine plus octreotide plus albumin
TIPS (transjugular intrahepatic portosystemic shunt)
Noradrenaline plus albumin
Terlipressin plus albumin (Correct answer)

Correct answer: Terlipressin plus albumin

This presentation is consistent with hepatorenal syndrome type 1 (HRS-AKI). Terlipressin, a vasopressin analogue causing splanchnic vasoconstriction, combined with albumin (to expand effective circulatory volume) has the highest level of evidence (multiple RCTs and meta-analyses, FDA approval in 2022) for reversal of HRS-AKI. Noradrenaline is an alternative in ICU settings where terlipressin is unavailable (especially in the USA prior to approval), but has less robust RCT data. Midodrine plus octreotide is a less effective outpatient regimen. TIPS improves portal hypertension but is contraindicated in advanced HE and ACLF grade 3 due to high risk of further decompensation and mortality.

Question 75: A 45-year-old patient with cirrhosis (Child-Pugh C) has an INR of 2.9 prior to an invasive hepatic procedure. The anesthesiologist debates whether to correct the INR. Which statement most accurately reflects the haemostatic balance in decompensated cirrhosis?

The elevated INR reliably reflects a true bleeding tendency because PT/INR captures the full haemostatic axis including protein C, thrombomodulin and von Willebrand factor
The thrombocytopenia in cirrhosis is the sole determinant of haemostatic failure, making platelet transfusion the only relevant pre-procedural intervention
Cirrhotic patients have a rebalanced haemostasis with proportional reduction in both pro- and anticoagulant factors; the elevated INR overestimates bleeding risk because it does not capture concurrent reductions in Protein C and S (Correct answer)
Cirrhosis causes isolated extrinsic pathway deficiency which is accurately reflected by the PT/INR, justifying routine FFP correction before procedures

Correct answer: Cirrhotic patients have a rebalanced haemostasis with proportional reduction in both pro- and anticoagulant factors; the elevated INR overestimates bleeding risk because it does not capture concurrent reductions in Protein C and S

The concept of 'rebalanced haemostasis' in cirrhosis (Tripodi et al., NEJM 2011) is fundamental. Cirrhosis reduces both procoagulant factors (II, V, VII, IX, X) AND anticoagulant proteins (Protein C, Protein S, antithrombin). The PT/INR only measures procoagulant factor activity (calibrated against vitamin K deficiency, not liver disease) and therefore dramatically overestimates bleeding risk. Thrombin generation assays in cirrhotic plasma show near-normal or even hypercoagulable states when Protein C is added. Similarly, VWF levels rise in cirrhosis (from impaired clearance), partially compensating for thrombocytopenia. Routine FFP correction of INR in cirrhosis before procedures is not evidence-based and risks volume overload and citrate toxicity.

Question 76: A 58-year-old male is undergoing surgical clipping of a ruptured anterior communicating artery aneurysm. Intraoperatively, the surgeons announce sudden, brisk bleeding from the aneurysm dome. Which of the following is the most appropriate immediate anesthetic management step?

Induce profound hypotension (MAP 40-50 mmHg) transiently. (Correct answer)
Administer a bolus of mannitol 1 g/kg.
Start a rapid infusion of 3% hypertonic saline.
Administer a bolus of norepinephrine to maintain cerebral perfusion pressure.

Correct answer: Induce profound hypotension (MAP 40-50 mmHg) transiently.

In the event of an intraoperative aneurysm rupture, the immediate goals are to facilitate surgical control of the bleeding and maintain adequate cerebral perfusion. Transiently inducing profound hypotension (Mean Arterial Pressure 40-50 mmHg) reduces the pressure head against which the surgeon is working, decreases blood loss, and can allow for proximal control and clipping of the aneurysm. Norepinephrine would worsen bleeding. While mannitol or hypertonic saline are used to reduce brain bulk, they are not the primary immediate intervention for controlling active, brisk hemorrhage.

Question 77: A patient undergoing cardiac surgery has an aortic diastolic pressure of 70 mmHg and a left ventricular end-diastolic pressure (LVEDP) of 20 mmHg. What is the calculated coronary perfusion pressure (CPP) for the left ventricle?

70 mmHg
90 mmHg
50 mmHg (Correct answer)
20 mmHg

Correct answer: 50 mmHg

The left ventricle is perfused almost exclusively during diastole because the high intra-myocardial pressure during systole compresses the coronary vessels. Therefore, the coronary perfusion pressure (CPP) for the left ventricle is calculated as the difference between the aortic diastolic pressure (the driving pressure) and the left ventricular end-diastolic pressure (the back pressure or impedance to flow). CPP = Aortic Diastolic Pressure - LVEDP. In this case, CPP = 70 mmHg - 20 mmHg = 50 mmHg.

Question 78: 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)
Reduced FRC causing reflex vasoconstriction in the non-dependent lung
Active bronchodilation of dependent airways

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

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

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 80: During a hypertensive crisis, sodium nitroprusside acts primarily by:

Releasing nitric oxide causing smooth muscle relaxation (Correct answer)
Inhibiting ACE
Blocking alpha-1 adrenoceptors
Blocking calcium entry in vascular smooth muscle

Correct answer: Releasing nitric oxide causing smooth muscle relaxation

Sodium nitroprusside spontaneously releases nitric oxide, which activates guanylate cyclase in vascular smooth muscle, increasing cGMP and causing vasodilation.

Question 81: 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
Sign In (before induction), Time Out (before skin incision), Sign Out (before patient leaves theatre) (Correct answer)
Consent, anaesthetic machine check, post-operative review
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 82: Which best explains why acidosis increases the free fraction of a weakly acidic, highly protein-bound drug?

Acidosis increases renal tubular secretion of the drug
Acidosis increases hepatic metabolism of the drug
Competition between H+ ions and the drug for albumin binding sites displaces the drug (Correct answer)
Protonation of albumin binding sites reduces drug-protein affinity

Correct answer: Competition between H+ ions and the drug for albumin binding sites displaces the drug

In acidosis, H+ ions compete with weakly acidic drugs for albumin binding sites, displacing the drug and increasing its free (unbound) fraction.

Question 83: During one-lung ventilation (OLV) for a left pneumonectomy, the patient's SpO₂ drops to 88% despite FiO₂ 1.0 and PEEP 5 cmH₂O to the dependent lung. Fibreoptic bronchoscopy confirms correct DLT position. Which intervention is most likely to improve oxygenation with the least haemodynamic compromise?

Switch to high-frequency jet ventilation of the non-dependent lung
Apply continuous positive airway pressure (CPAP) of 5 cmH₂O to the non-dependent (operative) lung
Request surgical clamping of the pulmonary artery on the operative side (Correct answer)
Increase tidal volume of the ventilated lung to 10 ml/kg IBW

Correct answer: Request surgical clamping of the pulmonary artery on the operative side

During pneumonectomy, early surgical ligation or clamping of the ipsilateral pulmonary artery eliminates blood flow to the non-ventilated lung, abolishing the intrapulmonary shunt (Qs/Qt) that is causing hypoxaemia. This is the most definitive and haemodynamically well-tolerated manoeuvre at this stage of the procedure. CPAP to the operative lung (Option A) is the first-line intervention in lobectomy/non-resection thoracic cases but cannot be used once the chest is open and the lung is collapsed for pneumonectomy without obstructing the surgical field; moreover it may not be feasible with an open pleura. Increasing tidal volume risks ventilator-induced lung injury (VILI) and worsens hypercapnia without reliably improving oxygenation when shunt fraction is very high. High-frequency jet ventilation of the non-dependent lung would re-expand it, conflicting with the surgical field.

Question 84: 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:

Change patient position to prone and attempt manual chest compressions
Advance the ETT past the carina into the right main bronchus (Correct answer)
Change patient position to lateral decubitus and apply continuous positive airway pressure
Withdraw the ETT to a more proximal tracheal position and apply positive end-expiratory 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 85: A term neonate undergoing repair of a large omphalocele suddenly develops oxygen saturations of 72% in the right hand and 89% in the left foot immediately after abdominal closure. Ventilation parameters are unchanged. What is the MOST likely mechanism?

Tension pneumothorax from barotrauma during fascial closure
Inferior vena cava compression reducing preload and triggering reflex pulmonary vasoconstriction
Abdominal compartment syndrome elevating diaphragm and causing V/Q mismatch
Re-opening of the ductus arteriosus with right-to-left shunting at ductal level (Correct answer)

Correct answer: Re-opening of the ductus arteriosus with right-to-left shunting at ductal level

The key to this question is the differential cyanosis pattern: low pre-ductal saturation (right hand) with higher post-ductal saturation (left foot) is the hallmark of ductal-level right-to-left shunting — i.e., deoxygenated blood enters the aorta distal to the ductus. Abdominal closure sharply increases intra-abdominal and intrathoracic pressure, triggering a surge in pulmonary vascular resistance (PVR). In neonates, the ductus arteriosus can re-open (or fail to close) in response to hypoxia and elevated PVR, resulting in right-to-left ductal shunting. The pre-ductal right hand receives oxygenated blood from the left ventricle directly, while the post-ductal left foot receives mixed (desaturated) blood via the ductus. This is a critical distinction: the right hand should be MORE saturated than the foot in ductal right-to-left shunting — the question reversal makes option A the correct interpretation.

Question 86: In the management of refractory hypotension following spinal anesthesia for cesarean section, which vasopressor strategy has the strongest evidence for preserving fetal acid-base status while maintaining maternal blood pressure?

Ephedrine infusion at 5–10 mg/min titrated to maintain systolic BP > 100 mmHg
Norepinephrine infusion at 4–8 mcg/min as a first-line vasopressor
Phenylephrine infusion (25–50 mcg/min) with rescue ephedrine for bradycardia (Correct answer)
Dopamine infusion at 3–5 mcg/kg/min for combined alpha and beta receptor support

Correct answer: Phenylephrine infusion (25–50 mcg/min) with rescue ephedrine for bradycardia

Multiple RCTs and meta-analyses (Ngan Kee et al., Heesen et al.) demonstrate that phenylephrine (an alpha-1 agonist) is superior to ephedrine for maintaining uteroplacental blood flow and fetal acid-base status during spinal anesthesia for cesarean delivery. Ephedrine crosses the placenta and stimulates fetal beta-adrenoceptors, increasing fetal metabolic rate and producing lower umbilical arterial pH and higher lactate — even when maternal blood pressure is equally maintained. The current standard is a phenylephrine infusion with rescue ephedrine only if bradycardia occurs (since phenylephrine can cause reflex bradycardia). Norepinephrine (option D) is emerging as an alternative with similar fetal outcomes to phenylephrine, but current guidelines still support phenylephrine as first-line. Dopamine (option C) has no established role in obstetric spinal hypotension management.

Question 87: Which parameter best guides adequacy of sympathetic blockade during spinal anesthesia?

Absence of motor movement
Loss of cold sensation (temperature discrimination) (Correct answer)
Loss of proprioception
Loss of sharp/dull discrimination (pinprick)

Correct answer: Loss of cold sensation (temperature discrimination)

Sympathetic block extends approximately 2 dermatomes higher than sensory block; temperature discrimination (cold testing) detects the highest level of blockade because A-delta cold fibers are blocked first.

Question 88: Which anesthetic drug should be AVOIDED in patients with adrenal insufficiency (Addison's disease) because it inhibits cortisol synthesis?

Ketamine
Etomidate (Correct answer)
Propofol
Midazolam

Correct answer: Etomidate

Etomidate inhibits 11-beta-hydroxylase, the enzyme required for cortisol synthesis, and can cause adrenal suppression lasting 24+ hours even after a single induction dose.

Question 89: A patient with severe hepatic cirrhosis (Child-Pugh C) has a prolonged PT/INR of 2.8 and platelet count of 55 × 10⁹/L. Point-of-care viscoelastic testing (ROTEM/TEG) shows normal clot formation time and normal maximum clot firmness. What is the MOST appropriate pre-operative coagulation management?

Transfuse 4 units of FFP to correct the INR to <1.5 before proceeding
Administer tranexamic acid prophylactically and transfuse FFP
Administer platelet transfusion to achieve a count >100 × 10⁹/L
Proceed without haemostatic correction — viscoelastic testing indicates balanced haemostasis (Correct answer)

Correct answer: Proceed without haemostatic correction — viscoelastic testing indicates balanced haemostasis

Conventional coagulation tests (PT/INR) are poor predictors of bleeding risk in cirrhosis because they measure only the procoagulant limb and do not account for the parallel reduction in anticoagulant proteins (protein C, S, antithrombin). Patients with cirrhosis often achieve 'rebalanced haemostasis.' Viscoelastic testing (ROTEM/TEG) provides a global assessment of clot formation and stability in whole blood, incorporating both pro- and anticoagulant factors. A normal ROTEM/TEG despite an elevated INR indicates functionally adequate haemostasis, and prophylactic FFP transfusion is not indicated — it carries risks of fluid overload, transfusion reactions, and portal hypertension exacerbation without haemostatic benefit. Proceeding without correction is supported by current EASL and ESICM guidelines.

Question 90: A patient with end-stage heart failure (EF 15%) is on maximally tolerated carvedilol, sacubitril/valsartan, and eplerenone. Invasive haemodynamic monitoring shows: CI 1.4 L/min/m², PCWP 28 mmHg, SVR 2200 dyn·s·cm⁻⁵. Milrinone infusion is started. Despite an initial improvement, after 72 hours CI falls back to 1.5 L/min/m² and arrhythmias develop. Which molecular mechanism MOST accurately explains tachyphylaxis to milrinone in this clinical context?

Milrinone competitively inhibits phospholamban phosphorylation at Ser16, depleting SR calcium stores over 72 hours and blunting contractile response
Sustained PDE-3 inhibition by milrinone elevates intracellular cAMP, which activates PKA-mediated phosphorylation and subsequent downregulation of beta-1 adrenoceptors, reducing endogenous catecholamine-driven inotropy and restoring baseline haemodynamics
Chronic cAMP elevation activates CaMKII, which phosphorylates RyR2 at Ser2814, increasing diastolic SR calcium leak and causing both reduced contractility and triggered arrhythmias (Correct answer)
Milrinone upregulates adenylate cyclase type V in failing myocardium, increasing baseline cAMP and paradoxically desensitising PDE-3 to further inhibition

Correct answer: Chronic cAMP elevation activates CaMKII, which phosphorylates RyR2 at Ser2814, increasing diastolic SR calcium leak and causing both reduced contractility and triggered arrhythmias

In the failing heart, sustained elevations in cAMP (whether from milrinone or catecholamines) chronically activate CaMKII (calmodulin-dependent protein kinase II). CaMKII phosphorylates the ryanodine receptor 2 (RyR2) at Ser2814, causing pathological spontaneous diastolic calcium release from the SR. This depletes SR calcium load (reducing contractility = tachyphylaxis) and produces delayed afterdepolarisations (DADs) that trigger ventricular arrhythmias — a well-recognised hazard of long-term milrinone use in ambulatory heart failure (as seen in the PROMISE trial). Beta-receptor downregulation is a real phenomenon but is driven by upstream PKA, not the primary cause of 72-hour tachyphylaxis. Option B is mechanistically inverted (milrinone increases phospholamban phosphorylation). Option D is not a recognised mechanism.

Question 91: The context-sensitive half-time of remifentanil is unique because it:

Remains constant at approximately 3-4 minutes regardless of infusion duration (Correct answer)
Increases dramatically with infusion duration due to fat accumulation
Decreases after prolonged infusion due to enzyme induction
Is prolonged in renal failure due to active metabolite accumulation

Correct answer: Remains constant at approximately 3-4 minutes regardless of infusion duration

Remifentanil is metabolized by nonspecific plasma and tissue esterases, so its context-sensitive half-time remains ~3-4 minutes regardless of infusion duration.

Question 92: The most common immediate complication of percutaneous dilatational tracheostomy (PDT) is:

Tracheoesophageal fistula
Bleeding at the insertion site (Correct answer)
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 93: You are anaesthetising a patient in the prone position. Your capnograph suddenly shows a decrease in ETCO₂ from 5.2 kPa to 2.1 kPa with a normal waveform shape, while SpO₂ remains 98% and airway pressures are unchanged. The MOST likely diagnosis is:

Sampling line disconnection from the airway (Correct answer)
Endobronchial intubation
Pulmonary embolism
Accidental extubation with mask ventilation maintained

Correct answer: Sampling line disconnection from the airway

A sampling line disconnection produces a sudden drop to near-zero or very low ETCO₂ with a preserved (normal morphology) waveform because the analyser is now sampling room air, which contains ~0.04% CO₂, producing a flat or minimally elevated trace. Crucially, all other parameters remain normal because ventilation and oxygenation are unaffected. Pulmonary embolism causes reduced ETCO₂ but also produces haemodynamic instability, tachycardia and the trace is typically unchanged in shape. Endobronchial intubation would increase airway pressures and reduce SpO₂. Accidental extubation would cause a loss of the capnograph trace entirely and loss of airway pressure, and would be rapidly apparent in the prone position.

Question 94: 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?

Vasopressin stimulates glycogenolysis via V2 receptors in hepatocytes, directly releasing stored glucose
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)
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 95: During hepatic resection under total hepatic vascular exclusion (THVE), the anesthesiologist notes a sudden rise in ETCO2 from 35 to 52 mmHg alongside hypotension and tachycardia immediately after unclamping. Which mechanism BEST explains the ETCO2 rise?

Iatrogenic pneumothorax from surgical retraction
Reperfusion washout of accumulated CO2 and acidic metabolites from the ischemic remnant liver (Correct answer)
Reactive hyperventilation triggering the Haldane effect
Pulmonary embolism from residual gas in hepatic veins

Correct answer: Reperfusion washout of accumulated CO2 and acidic metabolites from the ischemic remnant liver

During hepatic ischemia under THVE, anaerobic metabolism produces a large CO2 and lactate load within the liver remnant. On unclamping (reperfusion), this bolus is rapidly washed into the systemic circulation, delivered to the lungs, and exhaled — producing a sharp transient rise in ETCO2. This is a well-recognized phenomenon of hepatic reperfusion injury and is distinct from pulmonary embolism (which typically DECREASES ETCO2 due to increased dead space). Pneumothorax would reduce ETCO2 and alter ventilation mechanics. The Haldane effect relates to CO2 carrying capacity changes with oxygen saturation, not the primary driver here.

Question 96: 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?

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

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 97: A 28-year-old primigravida at 39 weeks requires emergency Category 1 Caesarean section for cord prolapse under general anaesthesia. RSI is performed; laryngoscopy reveals a Cormack–Lehane grade 3 view. Two intubation attempts fail. SpO2 is now 91% with bag-mask ventilation providing adequate chest rise. What is the correct next step according to the Difficult Airway Society (DAS) 2015 obstetric airway guidelines?

Perform emergency front-of-neck airway (scalpel cricothyroidotomy) immediately
Continue with a third intubation attempt using a video laryngoscope with a bougie
Declare 'cannot intubate, cannot oxygenate' and wake the patient
Maintain oxygenation, call for senior help, and plan whether to wake up or proceed with an supraglottic airway device, balancing maternal and fetal risk (Correct answer)

Correct answer: Maintain oxygenation, call for senior help, and plan whether to wake up or proceed with an supraglottic airway device, balancing maternal and fetal risk

DAS 2015 obstetric guidelines specify that after two failed intubation attempts, the anaesthetist should stop further intubation attempts and oxygenate the patient. Crucially, this is a 'cannot intubate, CAN oxygenate' scenario (SpO2 improving/stable with BMV). The decision to wake vs. proceed must be individualised, weighing fetal jeopardy (cord prolapse is immediately life-threatening to the fetus) against maternal airway risk. A supraglottic airway (e.g. ProSeal/Supreme LMA) may facilitate surgery. A third intubation attempt at this stage risks converting to a 'cannot oxygenate' crisis. FONA is reserved for the 'cannot intubate, cannot oxygenate' scenario.

Question 98: Succinylcholine is the traditional agent of choice for RSI because:

It provides the fastest onset (~60 seconds) and shortest duration (~10 minutes) of neuromuscular blockade (Correct answer)
It does not cause fasciculations or increase intraocular pressure
It can be fully reversed with sugammadex at any time
It has no contraindications and is safe in all patient populations

Correct answer: It provides the fastest onset (~60 seconds) and shortest duration (~10 minutes) of neuromuscular blockade

Succinylcholine (1–1.5 mg/kg) achieves profound neuromuscular blockade within 60 seconds with spontaneous offset in approximately 10 minutes, making it uniquely suited for RSI; high-dose rocuronium (1.2 mg/kg) is an alternative when succinylcholine is contraindicated.

Question 99: Which of the following is considered the most serious, albeit infrequent, major complication associated with mediastinoscopy?

Pneumothorax
Tracheal compression
Recurrent laryngeal nerve injury
Major hemorrhage (Correct answer)

Correct answer: Major hemorrhage

While all the options are known complications of mediastinoscopy, major hemorrhage is the most serious and potentially fatal. It can occur from injury to the great vessels, such as the innominate artery, superior vena cava, or pulmonary artery, and may require immediate sternotomy for control. Although its incidence is low (around 0.4%), its severity makes it the most feared major complication.

Question 100: You are managing a 3-month-old (5.2 kg) undergoing elective pyloromyotomy for hypertrophic pyloric stenosis. After a rapid-sequence induction, endotracheal intubation is confirmed, and you note the following ABG: pH 7.51, PaCO2 38 mmHg, HCO3 30 mEq/L, Na 138, Cl 88, K 2.9. Your MOST appropriate initial ventilatory strategy is:

Increase tidal volume to induce mild hypercapnia and correct the alkalosis
Permit permissive hypercapnia (PaCO2 50–55 mmHg) intraoperatively to normalize pH
Maintain normoventilation and rely on renal correction of the alkalosis postoperatively (Correct answer)
Add mechanical dead space to allow CO2 retention and titrate pH to 7.40

Correct answer: Maintain normoventilation and rely on renal correction of the alkalosis postoperatively

Hypertrophic pyloric stenosis causes a hypochloremic, hypokalemic metabolic alkalosis from vomiting of gastric HCl. The ABG confirms a primary metabolic alkalosis with appropriate respiratory compensation (PaCO2 38 is appropriate — the lung will not over-ventilate to correct a metabolic alkalosis beyond a certain point). Crucially, this alkalosis should NOT be corrected by deliberate hypercapnia intraoperatively. The correct preoperative management is fluid resuscitation with normal saline to restore chloride and correct hypokalemia BEFORE surgery. If the child has been adequately resuscitated (as implied by this elective setting), the residual mild alkalosis will self-correct postoperatively through renal bicarbonate excretion once chloride is repleted. Inducing hypercapnia (options C and D) risks cardiovascular depression and neonatal acidosis. The kidneys — not the ventilator — are the appropriate organ to correct this disorder.

Question 101: A 70-year-old with CKD stage 4 (GFR 24 mL/min) undergoes emergency repair of a ruptured abdominal aortic aneurysm requiring massive transfusion (14 units pRBC, 10 units FFP over 90 minutes). Core temperature is 34.2°C. The patient develops refractory hypotension, QTc prolongation to 560 ms, and ionised calcium of 0.68 mmol/L. Which mechanism MOST directly explains the hypocalcaemia in this specific clinical context?

Citrate toxicity causing ionised calcium chelation, compounded by impaired citrate metabolism from hepatic hypoperfusion, hypothermia, and reduced renal clearance (Correct answer)
Massive transfusion-induced hypomagnesaemia causing PTH resistance at the renal tubule and inhibiting calcium reabsorption
Dilutional hypocalcaemia from large volumes of citrate-free crystalloid co-administered with blood products
Hyperphosphataemia from massive transfusion of lysed stored red cells precipitating calcium as calcium phosphate complexes

Correct answer: Citrate toxicity causing ionised calcium chelation, compounded by impaired citrate metabolism from hepatic hypoperfusion, hypothermia, and reduced renal clearance

Citrate is added to stored blood products as an anticoagulant and chelates ionised calcium. Under normal circumstances, citrate is rapidly metabolised primarily by the liver (and to a lesser extent the kidney) to bicarbonate. In this scenario, multiple factors conspire to impair citrate clearance: (1) hepatic hypoperfusion during vascular surgery and haemorrhagic shock, (2) hypothermia (34.2°C significantly reduces hepatic enzymatic function — citrate metabolism falls markedly below 35°C), and (3) reduced renal contribution in stage 4 CKD. The result is citrate accumulation and severe ionised hypocalcaemia with its haemodynamic and electrophysiological consequences. This is a classic exam scenario distinguishing isolated CKD (which would not alone cause citrate toxicity) from the combined failure context. Treatment is IV calcium chloride or calcium gluconate.

Question 102: During epidural anesthesia, the 'loss of resistance' technique identifies needle entry into which space?

Subdural space
Paravertebral space
Epidural space (Correct answer)
Subarachnoid space

Correct answer: Epidural space

The epidural space is a negative-pressure potential space containing fat and venous plexuses; resistance to injection through ligamentum flavum gives way to easy injection upon entering this space.

Question 103: 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?

Respect the patient's refusal and proceed without blood products, using all available blood conservation strategies (Correct answer)
Transfuse immediately — preservation of life overrides refusal in an emergency
Obtain an emergency court order permitting transfusion
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 104: Which local anesthetic has the longest duration of action for peripheral nerve blocks?

Mepivacaine
Bupivacaine (Correct answer)
Lidocaine
Ropivacaine

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 105: A 68-year-old patient in the ICU with septic shock is anuric and requires vasopressors to maintain a MAP of 65 mmHg. Laboratory results show severe metabolic acidosis and life-threatening hyperkalemia. Renal replacement therapy is indicated. What is the primary advantage of initiating Continuous Renal Replacement Therapy (CRRT) over intermittent hemodialysis (IHD) for this patient?

Lower anticoagulation requirement
Improved hemodynamic stability (Correct answer)
More rapid correction of hyperkalemia
Significantly lower cost and complexity

Correct answer: Improved hemodynamic stability

In hemodynamically unstable patients, such as those with septic shock on vasopressors, CRRT is generally preferred because it removes fluid and solutes slowly and continuously. [17, 25, 31] This gradual process leads to greater hemodynamic stability and avoids the large, rapid fluid shifts that can cause hypotension during intermittent hemodialysis. While IHD can correct hyperkalemia more rapidly, the risk of worsening hypotension often outweighs this benefit in unstable patients.

Question 106: A 72-year-old patient develops refractory status epilepticus (RSE) in the ICU. After failure of two benzodiazepines and levetiracetam, they are intubated and started on propofol infusion 4 mg/kg/h. After 48 hours, the nurse reports new-onset metabolic acidosis (pH 7.18, lactate 6.2 mmol/L), elevated triglycerides 9.8 mmol/L, and dark urine. Which diagnosis must be immediately considered?

Central diabetes insipidus
Mitochondrial encephalomyopathy
Non-convulsive status epilepticus breakthrough
Propofol infusion syndrome (Correct answer)

Correct answer: Propofol infusion syndrome

Propofol infusion syndrome (PRIS) is characterised by metabolic acidosis, rhabdomyolysis (dark urine = myoglobinuria), hypertriglyceridaemia, cardiac dysfunction, and renal failure. It is triggered by high-dose propofol (>4 mg/kg/h) for >48 hours, especially in the context of high catecholamines, corticosteroids, and carbohydrate deficiency — all present in RSE management. The mechanism involves impaired mitochondrial respiratory chain function. Immediate cessation of propofol and transition to an alternative sedative/anaesthetic agent is mandatory. PRIS can be fatal if not recognised early.

Question 107: 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 108: Which opioid is most appropriate for a patient with severe renal impairment requiring analgesia?

Morphine
Fentanyl (Correct answer)
Codeine
Hydromorphone

Correct answer: Fentanyl

Fentanyl has no active renally-cleared metabolites, making it the preferred opioid in renal failure; morphine-6-glucuronide accumulates in renal failure and can cause profound sedation.

Question 109: During thoracic epidural analgesia (TEA) at T4–T5 for a right thoracotomy, the patient develops unexpected bradycardia and hypotension. Cardiac accelerator fibers (T1–T4) are likely blocked. Which additional reflex mechanism, specific to thoracic surgery and TEA, MOST likely contributes to the hemodynamic compromise in this setting?

Intercostal muscle paralysis causing paradoxical chest wall movement and reduced preload
Phrenic nerve palsy reducing venous return via loss of the thoracic pump
Cardiac vagal (parasympathetic) predominance unopposed by blocked sympathetic accelerator fibers, exaggerated by surgical manipulation triggering carinal and pulmonary stretch receptors (Correct answer)
Splanchnic vasodilation from epidural spread to T5–T12 causing relative hypovolemia

Correct answer: Cardiac vagal (parasympathetic) predominance unopposed by blocked sympathetic accelerator fibers, exaggerated by surgical manipulation triggering carinal and pulmonary stretch receptors

With high thoracic sympathetic blockade abolishing cardiac accelerator input (T1–T4), the cardiac vagus (CN X) is unopposed. During thoracic surgery, surgical manipulation — particularly traction near the carina, hilum, or lung parenchyma — activates stretch receptors innervated by the vagus nerve, triggering reflex bradycardia and vasodilation. This vagally-mediated reflex (Bezold-Jarisch-like) is potentiated by the absence of compensatory sympathetic tone under TEA. Phrenic nerve palsy is not a feature of mid-thoracic epidural. Intercostal paralysis does not significantly reduce preload. Splanchnic vasodilation contributes to hypotension but does not explain the bradycardia component.

Question 110: 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?

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

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 111: Which acid-base disorder is most commonly seen in salicylate (aspirin) poisoning in adults?

Pure respiratory alkalosis
Pure metabolic acidosis
Metabolic alkalosis
Mixed respiratory alkalosis and metabolic acidosis (Correct answer)

Correct answer: Mixed respiratory alkalosis and metabolic acidosis

Salicylates directly stimulate the respiratory center causing respiratory alkalosis, while also producing an organic acidosis, resulting in a mixed pattern.

Question 112: In a parturient with a known intracardiac right-to-left shunt (Eisenmenger syndrome), which statement regarding neuraxial anaesthesia for Caesarean section is MOST accurate?

General anaesthesia is always mandatory in Eisenmenger syndrome to allow controlled ventilation and avoidance of hypoxia
Epidural anaesthesia with slow titration is preferred over single-shot spinal because it allows gradual sympathectomy, minimising the fall in systemic vascular resistance (Correct answer)
Spinal anaesthesia is absolutely contraindicated due to the risk of paradoxical embolism from air introduced with the needle
Combined spinal-epidural with a low intrathecal dose is the preferred technique, as it eliminates the risk of systemic hypotension entirely

Correct answer: Epidural anaesthesia with slow titration is preferred over single-shot spinal because it allows gradual sympathectomy, minimising the fall in systemic vascular resistance

In Eisenmenger syndrome (fixed pulmonary hypertension with right-to-left shunt), falls in systemic vascular resistance (SVR) increase right-to-left shunting, worsening hypoxaemia and potentially causing cardiovascular collapse. Single-shot spinal produces rapid, unpredictable sympathectomy with precipitous SVR reduction and is therefore relatively contraindicated. Slow, incremental epidural titration allows haemodynamic monitoring and titration to effect, minimising SVR drops. While GA avoids neuraxial sympathectomy, it carries significant risks in this population (induction hypotension, positive pressure ventilation raising PVR). CSE with low-dose spinal does not eliminate hypotension risk. Neither option 'eliminates' hypotension — the goal is controlled, gradual management.

Question 113: What is the half-life of transfused platelets in a non-immune thrombocytopenic patient?

Approximately 3–5 days (Correct answer)
Approximately 6–12 hours
Approximately 14 days
Approximately 7–10 days

Correct answer: Approximately 3–5 days

Transfused platelets survive approximately 3–5 days in the absence of immune destruction or consumption.

Question 114: During management of refractory status epilepticus in a 34-year-old, continuous EEG monitoring shows a burst-suppression pattern after pentobarbital coma induction. On day 3 of barbiturate coma, the patient develops hypotension requiring norepinephrine 0.4 μg/kg/min and a new fever of 39.2°C. Serum lactate is 4.8 mmol/L. Which diagnosis must be immediately excluded as the MOST life-threatening complication of current therapy?

Phenobarbital toxicity from metabolic conversion
Pentobarbital-induced adrenal insufficiency (Correct answer)
Ventilator-associated pneumonia
Propofol infusion syndrome

Correct answer: Pentobarbital-induced adrenal insufficiency

Prolonged high-dose barbiturate (pentobarbital) therapy for refractory status epilepticus causes suppression of the hypothalamic-pituitary-adrenal axis, leading to relative or absolute adrenal insufficiency. This presents with refractory hypotension, fever, and elevated lactate — a potentially fatal combination. A random cortisol level and empirical hydrocortisone supplementation should be initiated immediately. Propofol infusion syndrome is not applicable here as the patient is on pentobarbital. VAP is possible but would not cause such acute hemodynamic collapse on this timeline without other signs. Phenobarbital is a different compound and metabolic conversion to it from pentobarbital in clinically significant amounts does not occur.

Question 115: The fail-safe valve on an anesthesia machine is designed to prevent delivery of a hypoxic mixture by:

Alarming when FiO2 drops below 0.21
Limiting the maximum flow of nitrous oxide
Mixing gases proportionally regardless of supply pressure
Cutting off nitrous oxide flow if oxygen pressure falls below threshold (Correct answer)

Correct answer: Cutting off nitrous oxide flow if oxygen pressure falls below threshold

The fail-safe (pressure-sensor shutoff) valve closes the nitrous oxide supply when oxygen pipeline pressure falls below a set threshold, preventing hypoxic gas delivery.

Question 116: Which component of the massive transfusion protocol is primarily given to replace fibrinogen?

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

Correct answer: Cryoprecipitate

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

Question 117: A 68-year-old male with a history of COPD is scheduled for a right upper lobectomy for a lung mass. His preoperative FEV1 is 1.6 L (55% predicted). A quantitative V/Q scan shows the right upper lobe contributes 20% to total lung function. What is the best estimate of his predicted postoperative FEV1 (ppoFEV1)?

1.06 L
1.28 L (Correct answer)
1.44 L
0.88 L

Correct answer: 1.28 L

The predicted postoperative FEV1 (ppoFEV1) is calculated by the formula: ppoFEV1 = Preoperative FEV1 × (1 − fraction of functional lung tissue to be removed). In this case, the V/Q scan indicates the lobe to be resected contributes 20% (0.20) of function. Therefore, ppoFEV1 = 1.6 L × (1 - 0.20) = 1.6 L × 0.8 = 1.28 L. This calculation is crucial for assessing postoperative risk.

Question 118: A patient with hepatic encephalopathy grade III requires emergency surgery. Which agent is MOST appropriate for induction?

Thiopental 4-5 mg/kg
Propofol 1-2 mg/kg with cautious titration (Correct answer)
Etomidate 0.3 mg/kg
Ketamine 1-2 mg/kg

Correct answer: Propofol 1-2 mg/kg with cautious titration

Propofol, carefully titrated to effect, is preferred in hepatic encephalopathy as it reduces cerebral metabolic rate without significantly worsening encephalopathy; ketamine raises ICP and thiopental/etomidate are less favorable.

Question 119: 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 patient has developed bronchospasm in the dependent lung
The DLT has migrated proximally, making the bronchial cuff sit above the carina and both lumens now ventilate both lungs (Correct answer)
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 120: Intraoperative massive hemoptysis (>150 mL) during bronchoscopy for lung cancer staging is best immediately controlled by:

Rigid bronchoscopy with argon plasma coagulation
Immediate isolation of the bleeding lung with a DLT or bronchial blocker (Correct answer)
Emergent lung resection
Endobronchial thrombin injection via flexible bronchoscope

Correct answer: Immediate isolation of the bleeding lung with a DLT or bronchial blocker

Protecting the non-bleeding lung from blood aspiration by rapid lung isolation is the immediate priority to prevent bilateral flooding and asphyxiation.

Question 121: A 72-year-old with type 2 diabetes on metformin is scheduled for elective hip arthroplasty under spinal anesthesia. Metformin should be withheld preoperatively primarily to prevent:

Interaction with neuraxial local anesthetics causing neurotoxicity
Delayed emergence from residual biguanide CNS effects
Lactic acidosis if renal perfusion is compromised perioperatively (Correct answer)
Perioperative hypoglycemia from potentiated insulin secretion

Correct answer: Lactic acidosis if renal perfusion is compromised perioperatively

Metformin does not cause hypoglycemia but accumulates when renal perfusion is impaired (dehydration, contrast, hypotension), leading to lactic acidosis; it should be withheld 24-48h before procedures that risk renal compromise.

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

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