Minimal occlusive volume is a safe and effective method for adjusting cuff pressure in mechanically ventilated patients

ABSTRACT The ideal cuff pressure (Pcuff) must prevent microaspiration of oropharyngeal secretions due to air leakage and avoid injury to the tracheal mucosa. Usually, monitoring consists of a manometer to keep the Pcuff between 20 and 30cmH2O. The minimal occlusive volume (MOV) method minimally inflates the cuff using a syringe so that no leakage occurs. This study aims to evaluate the ability of the minimal occlusive method to individualize the Pcuff adjustment in mechanically ventilated patients. Cross-sectional prospective study with 25 adult patients with more than 48 hours of mechanical ventilation. Cuff pressure was measured at two moments: initial and by MOV. The prevalence of Pcuff outside the normal range was 76%. Leakage in the initial measurement occurred in 9 patients, 4 of whom were within the reference values. The other 5 patients presented Pcuff<20cmH2O. In the adjustment by the MOV method, all patients presented Pcuff at the limit of normality. Patients without leakage with Pcuff>30cmH2O had a reduction when adjusted for MOV (45.4±9.6 against 28.5±1.6cmH2O; p<0.001). We can conclude that the minimal occlusive volume method was able to individualize the Pcuff within the reference values in all patients.

摘要
理想气囊压力（Pcuff）需既能避免因气体泄漏引发的口咽分泌物微量误吸，又可避免损伤气管黏膜。临床常规采用压力计进行监测，将Pcuff维持在20~30cmH₂O范围内。最小闭合容量（MOV）法通过注射器微量充盈气囊，直至无气体泄漏发生。本研究旨在评估最小闭合容量法对机械通气患者Pcuff的个体化调节效果。本研究为横断面前瞻性研究，纳入25例机械通气时长超过48小时的成年患者，分别于初始状态及采用MOV法调整后两个时间点测量气囊压力。结果显示，初始状态下Pcuff超出正常参考范围的患者比例为76%。初始测量时存在气体泄漏的患者共9例，其中4例的Pcuff处于参考值范围内，其余5例患者的Pcuff低于20cmH₂O。采用MOV法调整后，所有患者的Pcuff均处于正常参考范围区间内。初始无气体泄漏但Pcuff高于30cmH₂O的患者，经MOV法调整后Pcuff显著降低（调整前为45.4±9.6cmH₂O，调整后为28.5±1.6cmH₂O；p<0.001）。综上可知，最小闭合容量法可使所有患者的Pcuff个体化调整至正常参考范围内。