Study objective: Laryngotracheal injury or edema in the setting of intubation may narrow the upper airway and predispose toward postextubation stridor. The presence or absence of an audible airleak when the sealing balloon cuff of the endotracheal tube is deflated has been demonstrated to be a marker of laryngotracheal edema in high-risk patients. We hypothesized that (1) the volume of the cuff leak can be quantified in a general medical ICU population, and (2) the cuff leak volume can be correlated with likelihood of postextubation stridor.
Methods: Within 24 h of both the initiation and termination of mechanical ventilation, the cuff leak volume, defined as the difference between the inspiratory tidal volume and the averaged expiratory tidal volume while the cuff around the endotracheal tube was deflated, was recorded.
Results: In 100 consecutive intubations, the preextubation cuff leak volume was 349 +/- 163 mL [mean +/- SD]). Overall, 6% of extubations were accompanied by postextubation stridor. The mean cuff leak volume measured within 24 h of planned extubation was significantly lower in those who subsequently developed stridor in comparison to those who did not (180 +/- 157 mL vs 360 +/- 157 mL; p = 0.012). The positive predictive value for postextubation stridor in the setting of a cuff leak less than 110 mL was 0.80, the predictive value for absence of postextubation stridor with a cuff leak volume greater than 110 mL was 0.98, and the specificity of the test was 0.99. No other demographic factors or indexes related to mechanical ventilation were significantly different between the two groups.
Conclusions: A reduced cuff leak volume prior to extubation identifies a population at increased risk for postextubation stridor.