Monitoring: capnograph waveforms: 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 · Monitoring: capnograph waveforms

Sample item

A capnograph shows a sloping upstroke with no plateau (shark-fin pattern). What is the likely cause?

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

The answer and the reasoning

C. Bronchospasm or obstructed airflow

Obstruction delays gas emptying from alveoli with different time constants, producing a slanted rise and loss of the plateau. Rebreathing raises the baseline, and oesophageal intubation produces no trace.

Option by option

  • A. Cardiac arrest

    Cardiac arrest causes a rapid fall of EtCO2.

  • B. Oesophageal intubation

    Oesophageal intubation gives no sustained trace.

  • C. Bronchospasm or obstructed airflow (correct)

    Correct. A shark-fin trace indicates airway obstruction.

  • D. Rebreathing

    Rebreathing lifts the baseline.

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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Questions about this Anaesthesia question

What is the answer to this Anaesthesia question?

The best answer is C, Bronchospasm or obstructed airflow. Obstruction delays gas emptying from alveoli with different time constants, producing a slanted rise and loss of the plateau.

Why is "Cardiac arrest" not the answer?

Cardiac arrest causes a rapid fall of EtCO2.

Why is "Oesophageal intubation" not the answer?

Oesophageal intubation gives no sustained trace.

Why is "Rebreathing" not the answer?

Rebreathing lifts the baseline.

What concept does this question test?

It tests Monitoring: capnograph waveforms in Anaesthesia. Rebreathing raises the baseline, and oesophageal intubation produces no trace.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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 Monitoring: capnograph waveforms?

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.