持续气管内吹气方法的建立及压力释放阀在其中的应用

Continuous tracheal gas insufflation during pressure control ventilation with a pressure relief valve

目的 建立持续气管内吹气（ Ｃ Ｔ Ｇ Ｉ） 的方法，并探讨压力释放阀（ Ｐ Ｒ Ｖ） 在控制 Ｃ Ｔ Ｇ Ｉ所致气道压力过高中的作用。方法 自行设计、制作 Ｃ Ｔ Ｇ Ｉ装置； Ｐ Ｒ Ｖ 放置在呼吸机吸气管路中，其压力释放水平与设置的压力控制水平相同。选择健康犬９ 只，在相同压力控制水平及不同的吸呼比（２∶１ 或１∶２） 行 Ｐ Ｃ Ｖ（ 压力控制通气） ， Ｐ Ｃ Ｖ＋ Ｃ Ｔ Ｇ Ｉ（ Ｔ Ｇ Ｉ组） 及 Ｐ Ｃ Ｖ＋ Ｃ Ｔ Ｇ Ｉ＋ Ｐ Ｒ Ｖ（ Ｐ Ｒ Ｖ 组） 通气。对气体交换、呼吸力学、血流动力学和氧动力学指标进行监测。结果 在同一吸呼比， Ｔ Ｇ Ｉ 组气道吸气峰压（ Ｐ Ｉ Ｐ） 显著超过 Ｐ Ｒ Ｖ 组和 Ｐ Ｃ Ｖ 组（ Ｐ＜ ００１） ， Ｐ Ｒ Ｖ 组与 Ｐ Ｃ Ｖ 组相比差异无显著性；在不同吸呼比， Ｔ Ｇ Ｉ（２∶１） 组 Ｐ Ｉ Ｐ显著高于 Ｔ Ｇ Ｉ（１∶２） 组（ Ｐ＜ ００１） ； Ｔ Ｇ Ｉ组及 Ｐ Ｒ Ｖ 组 Ｐａ Ｃ Ｏ２ 较 Ｐ Ｃ Ｖ 组明显下降， Ｔ Ｇ Ｉ组较 Ｐ Ｒ Ｖ 组下降更明显； Ｐａ Ｏ２ 、血流动力学和氧动力学指标在各组间差异无显著性。结论 本研究设计和制作的 Ｃ Ｔ Ｇ Ｉ能有效改善肺泡通气，对血流动力学和氧动力学无显著影响， Ｐ Ｒ Ｖ 为安全使用 Ｃ

Objective To establish the method of continuous tracheal gas insufflation (CTGI) and investigate the role of pressure relief valve (PRV) in limiting high peak airway pressure induced by CTGI Methods CTGI device was made by authors Nine healthy mongrel dogs were mechanically ventilated by using Evita 2 (Drager Inc ) PRV was inserted into the ventilatory circuit for selected experiment steps and adjusted a threshold pressure equal to the preset inspiratoy pressure PCV, PCV+CTGI (TGI group) and PCV+CTGI+PRV (PRV group) were conducted in different inspiration/expiration (I/E) ratio of 1∶2 and 2∶1 Gas exchange, lung mechanics and hemodynamics status were monitored at the constant set inspiratoy pressure of PCV Results At the same I/E ratio, peak airway pressure in TGI group was higher than that of PRV and PCV group ( P <0 01), whereas PRV group maintained the preset inspiratory pressure as PCV group. At the different I/E ratio, peak airway pressure in TGI (2∶1) group was higher than that of TGI (1∶2) group( P <0 01). PaCO 2 in TGI and PRV group decreased significantly than that of PCV, TGI group was more lower than PRV group PaO 2, hemodynamics and oxygenation remained unchanged in all groups Conclusions The CTGI device is effective in improving alveolar ventilation with no significant influence on hemodynamics and oxygenation; A pressure relief valve is necessary to ensure the safe use of CTGI