Title: Does a cuff-leak mean anything?
题目：气囊放气在拔管中有什么意义？
Author 作者: Haney Mallemat

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.
在急诊科已插管的病人偶尔会符合一些拔管的标准。拔管并不是没有危险的，约30％的病人会因为拔管后喉头和上呼吸道水肿而出现呼吸困难，有的病人可能需要再插管。
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:
危重病医生在拔管前通常要进行一个短暂的‘气囊放气’试验（通过气管导管气囊放气以确定是否导管气囊周围有漏气的现象），间接发现上呼吸道水肿的存在，进而确定再插管的可能性。气囊放气试验在放掉气管导管气囊后，应用如下的一个或几个方法：
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.
用呼吸机来测量吸气和呼气时的潮气量差别，如有差别，则证实气管导管周围有漏气，标志着没有明显的气道水肿。
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.
用听诊的方式检查机械通气时导管周围的漏气，如有漏气，则证实气管导管周围有漏气，标志着没有明显的气道水肿。
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.
将病人与呼吸机分开，在病人自主呼吸时堵住气管导管，如听到漏气，则证实气管导管周围有漏气，标志着没有明显的气道水肿。

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.
Ochoa等人发表了一个文献综述，以确定用‘气囊放气’试验预测拔管前气道水肿的存在。他们的结论是，阳性试验（没有漏气）意味着上呼吸道梗阻和再插管的可能性很高。而阴性试验并不能够可靠地排除上呼吸道水肿或再插管的可能性。
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.
结论：在拔管前，没有任何一个试验可以可靠的预测没有上呼吸道水肿。因此，在急诊科里拔管后，要对病人进行严密观察，将呼吸设备放在附近。
References 参考文献
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