UMEM Educational Pearls

Title: Does a cuff-leak mean anything?

Posted: 9/25/2012 by Haney Mallemat, MD
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Intubated patients may occasionally meet certain criteria for extubation while in the Emergency Department. Extubation is not without its risk, however, as up to 30% of patients have respiratory distress secondary to laryngeal and upper airway edema, with some patients requiring re-intubation.

Prior to extubation, Intensivists use a brief “cuff-leak” test (deflation of the endotracheal balloon to assess the presence or absence of an air-leak around the tube) to indirectly screen for the presence of upper airway edema and ultimately the risk of re-intubation. The cuff-leak test is performed by deflating the endotracheal balloon followed by one or more of the following maneuvers:

Using the ventilator to measure the difference between inspired and expired tidal volumes; if there is a difference in the measured volumes, then air is “leaking” around the endotracheal tube, implying minimal airway edema.
Auscultation for an air “leak” around the tube during mechanical ventilation; auscultation of a leak implies that air is passing around the tube and minimal airway edema is present.
Disconnecting the patient from the ventilator and occluding the endotracheal tube during spontaneous breathing; auscultation of a leak implies that there is air passing around the tube and minimal airway edema is present.

Ochoa et al. performed a systematic review to determine the accuracy of the “cuff-leak” test to predict upper airway edema prior to extubation. The authors concluded that a positive cuff-leak test (i.e., absence of an air-leak) indicates an elevated risk of upper airway obstruction and re-intubation. A negative cuff-leak test (i.e., presence of an air-leak), however, does not reliably exclude the presence of upper airway edema or the need for subsequent re-intubation.

Bottom line: No test prior to extubation reliably predicts the absence of upper airway edema. Patients extubated in the Emergency Department require close observation with airway equipment located nearby.

References

Ochoa, ME et al. Cuff-leak test for the diagnosis of upper airway obstruction in adults: A systematic review and meta-analysis. Intensive Care Med (2009) 35:1171–1179

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