Monitoring: 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

Sample item

During a laparoscopic cholecystectomy, there is an abrupt fall in end-tidal CO2 from 38 to 10 mmHg with hypotension, tachycardia and a mill-wheel murmur. What is the most likely cause and the next immediate step?

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

The answer and the reasoning

A. Venous gas embolism; stop insufflation, release pneumoperitoneum and place the patient head-down on the left side

A sudden fall in ETCO2 with hypotension and a mill-wheel murmur indicates a gas embolus, which increases dead space and obstructs the right ventricular outflow. Insufflation is stopped, the pneumoperitoneum released, 100% oxygen given and the patient placed left lateral head-down (Durant position). Aspiration through a central line may be attempted.

Option by option

  • A. Venous gas embolism; stop insufflation, release pneumoperitoneum and place the patient head-down on the left side (correct)

    Correct. Sudden ETCO2 fall plus hypotension and a mill-wheel murmur point to gas embolism.

  • B. Tension pneumothorax; perform needle decompression only

    Tension pneumothorax raises airway pressure and a mill-wheel murmur is not a feature of it.

  • C. Malignant hyperthermia; give dantrolene

    Malignant hyperthermia causes a rise in ETCO2, not a fall.

  • D. Oesophageal intubation; remove the tube

    Oesophageal intubation would give no CO2 trace from the start, not an abrupt fall mid-procedure.

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.

More Anaesthesia questions

Questions about this Anaesthesia question

What is the answer to this Anaesthesia question?

The best answer is A, Venous gas embolism; stop insufflation, release pneumoperitoneum and place the patient head-down on the left side. A sudden fall in ETCO2 with hypotension and a mill-wheel murmur indicates a gas embolus, which increases dead space and obstructs the right ventricular outflow.

Why is "Tension pneumothorax; perform needle decompression only" not the answer?

Tension pneumothorax raises airway pressure and a mill-wheel murmur is not a feature of it.

Why is "Malignant hyperthermia; give dantrolene" not the answer?

Malignant hyperthermia causes a rise in ETCO2, not a fall.

Why is "Oesophageal intubation; remove the tube" not the answer?

Oesophageal intubation would give no CO2 trace from the start, not an abrupt fall mid-procedure.

What concept does this question test?

It tests Monitoring in Anaesthesia. Insufflation is stopped, the pneumoperitoneum released, 100% oxygen given and the patient placed left lateral head-down (Durant position). Aspiration through a central line may be attempted.

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 Monitoring?

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.