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Anaesthesia · Basic resuscitation: ventilation targets after return of circulation
Sample itemA comatose patient is ventilated after return of spontaneous circulation, and the arterial PaCO2 is 24 mmHg. What is the appropriate ventilation goal?
Original practice item, not a recalled exam question. Nothing here is recorded.
The answer and the reasoning
B. Normocapnia, PaCO2 about 35 to 45 mmHg
Hypocapnia causes cerebral vasoconstriction and reduces cerebral blood flow in a brain that is already vulnerable to ischaemia after arrest. Ventilation after return of circulation should aim for normal PaCO2, avoiding both hyperventilation and hypercapnia.
Option by option
A. Permissive hypercapnia with PaCO2 near 60 mmHg
Hypercapnia dilates cerebral vessels, can raise intracranial pressure and is not the goal.
B. Normocapnia, PaCO2 about 35 to 45 mmHg (correct)
Correct. Normal carbon dioxide levels preserve cerebral blood flow after arrest.
C. Hypocapnia to lower intracranial pressure further
Hypocapnia reduces cerebral blood flow and risks further ischaemic injury.
D. Marked hypocapnia below 20 mmHg for brain protection
Marked hypocapnia worsens cerebral ischaemia and has no neuroprotective role.
Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.
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