Cardiorespiratory arrest and post-arrest care — formative SAQs

SAQ 1 (10 marks)

A 4-year-old boy is brought to the emergency department after a witnessed collapse at home. He is unresponsive, takes occasional gasping breaths, and has no central pulse. His weight is 16 kg.[2]

Question. Outline your immediate resuscitation over the first 5 minutes, including the drugs and defibrillation strategy you would use if the initial rhythm were (a) asystole and (b) ventricular fibrillation. (7 marks) State three features that would confirm return of spontaneous circulation. (3 marks)[2][3]

Model answer

Recognise the arrest within 10 seconds: unresponsive, gasping, no central pulse. Call for help, start high-quality chest compressions at once — lower half of the sternum, depth about one third of the anteroposterior chest (about 5 cm in a 4-year-old), rate 100 to 120 per minute, full recoil, minimised interruptions, and ventilate with 100 percent oxygen using a bag-valve-mask, two rescuers giving 15 compressions to 2 ventilations.[2]

Attach a cardiac monitor and establish intraosseous access early. Adrenaline 10 micrograms per kg IV or IO (that is 0.1 mL per kg of 1 in 10,000 — about 1.6 mL for 16 kg) every 3 to 5 minutes.[2][3]

(a) Asystole is non-shockable: continue CPR, give adrenaline as soon as access is established and every 3 to 5 minutes, and hunt for and correct the reversible causes (the 4 Hs and 4 Ts), starting with hypoxia and hypovolaemia. Give a 10 to 20 mL per kg bolus of isotonic crystalloid for suspected shock, reassessing carefully.[2]

(b) Ventricular fibrillation is shockable: defibrillate at 2 to 4 J per kg (32 to 64 J for 16 kg) using a biphasic defibrillator, resume compressions immediately, and give adrenaline after the second shock. For refractory VF give amiodarone 5 mg per kg (80 mg for 16 kg) after the third shock, escalating shock energy to at least 4 J per kg up to a maximum of 10 J per kg.[2][3]

ROSC is confirmed by a palpable central pulse returning, a sudden rise in end-tidal CO2 on capnography, and an organised rhythm with a measurable blood pressure on the monitor.[2]

SAQ 2 (10 marks)

A 7-year-old girl is admitted to PICU six hours after achieving ROSC following a drowning-related out-of-hospital arrest. She is intubated, sedated and comatose. Her temperature is 38.1 degrees C, SpO2 is 100 percent on FiO2 1.0, and her mean arterial pressure is 45 mmHg.[1]

Question. Describe the post-arrest care bundle you would deliver over the next 24 hours, justifying each target with the evidence. (8 marks) Outline how and when you would prognosticate her neurologic outcome. (2 marks)[1][3]

Model answer

Run the bundle as a single simultaneous package. Targeted temperature management: maintain 36 to 37.5 degrees C with active normothermia and treat her fever of 38.1 degrees C now with paracetamol and surface cooling — the THAPCA trials showed therapeutic hypothermia is not superior to normothermia, and fever worsens secondary brain injury.[1][5]

Oxygenation: wean FiO2 to the lowest value keeping SpO2 at 94 to 99 percent; her current SpO2 of 100 percent on FiO2 1.0 is hyperoxia, which observational data link to worse outcome.[1]

Ventilation: target normocarbia PaCO2 35 to 45 mmHg (4.7 to 6.0 kPa) with lung-protective settings, and avoid prophylactic hyperventilation, which causes cerebral vasoconstriction.[1]

Haemodynamics: her mean arterial pressure of 45 mmHg is hypotension, independently associated with death and poor neurologic outcome — start a vasoactive infusion (adrenaline or noradrenaline, adding milrinone for low cardiac output) to restore an age-appropriate MAP, guided by the post-arrest blood-pressure thresholds identified in the ICU-Resuscitation study.[1][9]

Glucose: avoid hypoglycaemia and marked hyperglycaemia with point-of-care monitoring. Seizures: apply continuous EEG and treat clinical and electrographic seizures. Keep the head midline and elevated 30 degrees.[1]

Prognostication is delayed and multimodal: wait at least 72 hours after ROSC (and longer while she is on targeted temperature management and sedation), then combine the neurologic examination, continuous EEG background and reactivity, somatosensory evoked potentials, neuroimaging and biomarkers into a consensus judgement, never on a single early examination or one EEG.[1]