动态监测气管导管气囊压力，观察不同因素作用下气囊压力的动态变化；探讨气管导管气囊渗漏的机制并指导防渗漏发生。

（1）使用压力传感器连接气囊和心电监护仪，动态监测气囊压力的波形变化，并观察呼吸、吸痰、咳嗽、上调呼气末正压通气（PEEP）等情况下气囊压力的变化。（2）将不同型号气管导管插入模拟气管（注射器）内，气囊注气至压力为25~30 cmH₂O（1 cmH₂O=0.098 kPa）；注入含有亚甲基蓝的0.9%NaCl稀释液模拟气囊上分泌物，探讨气管导管气囊渗漏的机制，指导气囊防渗漏的发生。

机械通气患者气囊压力随呼吸呈现周期性变化，与平静呼吸时气囊压力相比，吸痰、咳嗽时气囊压力均显著升高，差异有统计学意义[（27.95±2.72）mmHg vs（20.32±2.08）mmHg，t=0.14，P<0.01；（28.68±2.93）mmHg vs （20.32±2.08）mmHg，t=0.03，P<0.01；1 mmHg=0.133 kPa]；PEEP增加2 cmH₂O以上时，气囊压力升高至（24.12±2.94）mmHg，差异有统计学意义（t=0.01，P<0.01）；气囊压力不足时，压力波形呈一直线。体外渗漏模拟试验显示，与7号气管导管相比，8号气管导管气囊外径相对气管内径偏大气囊渗漏显著增加，差异有统计学意义（P<0.05）；气囊外径相对气管内径偏小时，气囊上方分泌物沿气囊与气管间隙呈袖套状渗漏。气管导管呈30°~45°倾斜位时，需注意气囊上导管外壁引流管口水平面以下分泌物潴留及渗漏。

气管导管气囊压力受多种因素影响而呈现动态变化，需个体化设置并动态监测、实时调整气囊压力。选择与气管相匹配的气管导管型号可降低气囊渗漏的发生。

To dynamically monitor the intracuff pressure of endotracheal tube and study the mechanism of leakage around endotracheal tube cuff to prevent the leakage.

(1) The disposable pressure sensor was used to connect endotracheal tube cuff and monitor and dynamically present the intracuff pressure waveform. The changes in intracuff pressure with breathings, sputum suctions, coughs, and upregulated PEEP were observed and recorded. (2) Different types of endotracheal tubes were inserted into the simulated tracheas (syringes) with intracuff pressure up to 25-30 cmH₂O, Methylene blue diluted with normal saline was used to simulate above cuff secretions and to explore the mechanism of fluid leakage past endotracheal tubes.

The intracuff pressures of patients on mechanical ventilation change periodically with breathing, compared with the cuff pressure during normal breathing [(20.32±2.08) mmHg], the cuff pressure significantly increased during sputum suction [ (27.95±2.72) mmHg] (t=0.14, P<0.01) and cough [(28.68±2.93) mmHg] (t=0.03, P<0.01); when PEEP increased by more than 2 cmH₂O, the cuff pressure increased to (24.12±2.94) mmHg (t=0.01, P<0.01); when the cuff pressure was insufficient, the pressure waveform was flat. The vitro leaking simulation test showed that compared with the No.7 endotracheal tube, the leakage of No.8 endotracheal tube balloon significantly increased (P<0.05), when the outer diameter of the inflated cuff was smaller than the inner diameter of the simulated trachea, the liquid above the cuff leaked through the gap between the cuff and the trachea in a sleeve shape.

The intracuff pressure can be affected by various factors and need individualized settings, and dynamic monitoring and adjustment. An endotracheal tube matching the trachea may reduce the leakage past the cuff.