ACLS: end-tidal CO2 and prognosis: practice question

A Anaesthesia question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Anaesthesia · ACLS: end-tidal CO2 and prognosis

Sample item

After 20 minutes of advanced life support in an intubated patient, the end-tidal CO2 remains below 10 mmHg. How is this interpreted?

AIt indicates return of circulationBIt indicates adequate compressionsCIt proves that resuscitation must stop immediatelyDIt is one factor suggesting a very low chance of ROSC, to be considered with other findings

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. It is one factor suggesting a very low chance of ROSC, to be considered with other findings

A persistently low ETCO2 during CPR reflects poor cardiac output and is associated with poor outcome. It should not be used alone to stop resuscitation but forms part of multimodal decision-making. A sudden rise suggests ROSC.

Option by option

A. It indicates return of circulation
ROSC causes a sudden rise in ETCO2.
B. It indicates adequate compressions
Adequate compressions give a higher ETCO2.
C. It proves that resuscitation must stop immediately
It should not be the sole basis for stopping.
D. It is one factor suggesting a very low chance of ROSC, to be considered with other findings (correct)
Correct. It is a poor prognostic marker to be combined with other factors.

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.

Questions about this Anaesthesia question

What is the answer to this Anaesthesia question?

The best answer is D, It is one factor suggesting a very low chance of ROSC, to be considered with other findings. A persistently low ETCO2 during CPR reflects poor cardiac output and is associated with poor outcome.

Why is "It indicates return of circulation" not the answer?

ROSC causes a sudden rise in ETCO2.

Why is "It indicates adequate compressions" not the answer?

Adequate compressions give a higher ETCO2.

Why is "It proves that resuscitation must stop immediately" not the answer?

It should not be the sole basis for stopping.

What concept does this question test?

It tests ACLS: end-tidal CO2 and prognosis in Anaesthesia. It should not be used alone to stop resuscitation but forms part of multimodal decision-making. A sudden rise suggests ROSC.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study ACLS: end-tidal CO2 and prognosis?

Make a table of each agent, its key advantage and its main side effect. Then use the flashcards and the other Anaesthesia questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.