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Anaesthesia · Respiratory physiology and ventilation: curriculum recognition
Sample itemA ventilator trace shows every breath delivering the same preset quantity of gas with a square flow waveform, while the peak airway pressure climbs as the patient's lungs become stiffer. Which mode is in use?
Original practice item, not a recalled exam question. Nothing here is recorded.
The answer and the reasoning
B. Volume-controlled ventilation
In volume-controlled ventilation the set breath is delivered at constant flow, so the pressure varies with compliance and resistance while the delivered volume is guaranteed. In pressure-controlled modes the pressure is set and the volume varies.
Option by option
A. Pressure-controlled ventilation
In this mode the pressure is set and the delivered volume changes with compliance.
B. Volume-controlled ventilation (correct)
Correct. Guaranteed breath size with a pressure that varies is the feature of this mode.
C. Pressure support ventilation
This is a patient-triggered assist mode with a set inspiratory boost and variable volume.
D. Continuous positive airway pressure
This delivers a constant baseline pressure with no set breaths.
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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