Emergency Medicine Flashcards

A 58-year-old man presents with sudden-onset severe chest pain radiating to the back. BP is 178/92 mmHg in the right arm and 134/78 mmHg in the left arm. CT angiography confirms a Type A aortic dissection. Which of the following is the MOST appropriate initial pharmacological management?

Answer: IV labetalol to reduce heart rate to <60 bpm and SBP to <120 mmHg before surgical referral

In Type A aortic dissection, the priority is to reduce aortic wall stress by lowering both heart rate and blood pressure. Beta-blockers (e.g., labetalol or esmolol) are first-line to target HR <60 bpm and SBP 100–120 mmHg, thereby reducing dP/dt (rate of pressure rise). Nitroprusside alone is contraindicated without prior beta-blockade as it causes reflex tachycardia, worsening shear stress. Heparin and thrombolytics are absolutely contraindicated. Vasopressors worsen dissection by increasing wall tension.

A 34-year-old woman is brought in after an intentional overdose of sustained-release verapamil (approximately 4g). She is bradycardic (HR 38 bpm), hypotensive (BP 70/40 mmHg), and has a serum glucose of 9.2 mmol/L. Atropine and calcium gluconate have been given with minimal effect. Which intervention has the strongest evidence for refractory calcium channel blocker toxicity?

Answer: High-dose insulin euglycaemic therapy (HIET) at 1 unit/kg/hr with dextrose infusion

High-dose insulin euglycaemic therapy (HIET) is the cornerstone of refractory calcium channel blocker toxicity management. Cardiac myocytes in CCB toxicity shift to glucose as their primary fuel; insulin facilitates this uptake and improves inotropy. The modest hyperglycaemia seen here (9.2 mmol/L) reflects toxin-mediated insulin resistance, not adequate metabolic compensation. Glucagon has theoretical benefit but poor clinical evidence and causes vomiting. Transcutaneous/transvenous pacing addresses rate but not myocardial contractility. Lipid emulsion is used for lipophilic agents like bupivacaine but has very limited evidence for verapamil specifically.

During resuscitation of a patient in refractory ventricular fibrillation, three defibrillation attempts, amiodarone 300 mg, and lidocaine have been administered. The patient remains in VF. Which of the following represents the MOST evidence-based next step?

Answer: Switching to vector change defibrillation using anterior-posterior pad positioning

Vector change defibrillation (changing pad position from anterior-lateral to anterior-posterior) is a well-supported strategy for refractory VF and is recommended in the 2021 ERC guidelines. It alters the electrical vector through the myocardium, potentially depolarising cells resistant to the original vector. DSED has emerging evidence (notably the DOSE VF trial, 2022) showing benefit, but guideline incorporation is still evolving. Standard defibrillators are capped at 360 J and increasing beyond manufacturer limits is not recommended. Magnesium is indicated specifically for torsades de pointes-related VF, not refractory VF of other causes.

A 67-year-old male presents with acute altered consciousness, BP 210/130 mmHg, papilloedema, and serum creatinine 320 µmol/L (baseline unknown). MRI shows posterior reversible encephalopathy syndrome (PRES). Which of the following statements regarding blood pressure management is CORRECT?

Answer: MAP should be reduced by no more than 25% within the first hour to avoid cerebral ischaemia

In hypertensive emergency complicated by PRES, rapid overcorrection of BP is dangerous and can precipitate cerebral ischaemia due to impaired autoregulation. Guidelines recommend reducing MAP by no more than 25% in the first hour, then targeting 160/100 mmHg over the next 2–6 hours. PRES is a radiological diagnosis that does not constitute a contraindication to gradual BP reduction but does mandate avoiding overshoot. Aggressive normalisation risks watershed infarction. Thrombolysis is contraindicated in PRES (it is not ischaemic stroke). Nitroprusside can cause cyanide toxicity with prolonged use and does not directly reduce cerebral oedema.

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

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

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

A 44-year-old woman with known alcohol use disorder presents obtunded, with a core temperature of 28.5°C following cold-water immersion. Her ECG shows an Osborn (J) wave, HR 38 bpm with a wide QRS, and BP 60/40 mmHg. Which of the following is the MOST appropriate immediate intervention?

Answer: Extracorporeal membrane oxygenation (ECMO) rewarming if cardiac arrest occurs or haemodynamic instability is refractory to passive rewarming

Severe accidental hypothermia (30°C. Antiarrhythmics are ineffective in hypothermic VF. Active external rewarming is appropriate for mild-moderate cases but is insufficient for severe cardiovascular compromise; it also risks afterdrop (core temperature paradox). The principle 'no one is dead until warm and dead' applies — CPR must continue until rewarming is achieved.