Miller R L, Cole R P
Department of Medicine, Columbia-Presbyterian Medical Center, New York, NY 10032, USA.
Chest. 1996 Oct;110(4):1035-40. doi: 10.1378/chest.110.4.1035.
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.
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.
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.
A reduced cuff leak volume prior to extubation identifies a population at increased risk for postextubation stridor.
气管插管时发生的喉气管损伤或水肿可能会使上呼吸道变窄，并易于引发拔管后喘鸣。对于高危患者，气管导管密封气囊放气时是否存在可闻及的漏气已被证明是喉气管水肿的一个指标。我们假设：（1）在普通内科重症监护病房人群中可以对气囊漏气量进行量化；（2）气囊漏气量与拔管后喘鸣的可能性相关。
在机械通气开始和结束后的24小时内，记录气囊漏气量，其定义为气管导管周围气囊放气时吸气潮气量与平均呼气潮气量之差。
在连续100例插管病例中，拔管前气囊漏气量为349±163毫升[平均值±标准差]）。总体而言，6%的拔管伴有拔管后喘鸣。与未发生喘鸣的患者相比，随后发生喘鸣的患者在计划拔管后24小时内测得的平均气囊漏气量显著更低（180±157毫升对360±157毫升；p = 0.012）。气囊漏气量小于110毫升时拔管后喘鸣的阳性预测值为0.80，气囊漏气量大于110毫升时无拔管后喘鸣的预测值为0.98，该检测的特异性为0.99。两组之间的其他人口统计学因素或与机械通气相关的指标无显著差异。
拔管前气囊漏气量减少表明患者发生拔管后喘鸣的风险增加。
