Question:medium
Which of the following does the capnograph image below depict?
Which of the following does the capnograph image below depict?
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A single notch dipping into the phase III plateau points to returning patient effort.
Updated On: Jun 23, 2026
- During inspiration
- Inspiration with cardiac oscillations
- During expiration
- Spontaneous respiration
Show Solution
The Correct Option is D
Solution and Explanation
Clinical pearl: The curare cleft is the capnograph's way of telling you the paralysis is fading.
Picture the alveolar plateau (phase III) as a flat-topped box. When a notch suddenly carves into that flat top, the diaphragm has fired on its own and briefly diluted the expired CO2, so the trace dips. This is the curare cleft, and its presence on a ventilated patient signals spontaneous respiratory effort returning, classically as a neuromuscular blocker wears off.
Option elimination: A capnograph trace at true inspiration sits near zero, not on the plateau, so 'during inspiration' is out. 'Inspiration with cardiac oscillations' would give tiny, regular, heartbeat-timed ripples rather than one deep cleft. 'During expiration' just names a phase and does not explain the notch. That leaves spontaneous respiration as the answer.
Mnemonic: Curare notch = the curarised patient is starting to breathe back.
Ref: Miller's Anesthesia, 8th edition.
Picture the alveolar plateau (phase III) as a flat-topped box. When a notch suddenly carves into that flat top, the diaphragm has fired on its own and briefly diluted the expired CO2, so the trace dips. This is the curare cleft, and its presence on a ventilated patient signals spontaneous respiratory effort returning, classically as a neuromuscular blocker wears off.
Option elimination: A capnograph trace at true inspiration sits near zero, not on the plateau, so 'during inspiration' is out. 'Inspiration with cardiac oscillations' would give tiny, regular, heartbeat-timed ripples rather than one deep cleft. 'During expiration' just names a phase and does not explain the notch. That leaves spontaneous respiration as the answer.
Mnemonic: Curare notch = the curarised patient is starting to breathe back.
Ref: Miller's Anesthesia, 8th edition.
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