【摘要 】 目的 建立持续气管内吹气(CTGI)的方法，并探讨压力释放阀(PRV)在控制CTGI所致气道压力过高中的作用。方法 自行设计、制作CTGI装置；PRV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PCV(压力控制通气)，PCV+CTGI(TGI组)及PCV+CTGI+PRV(PRV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，TGI组气道吸气峰压(PIP)显著超过PRV组和PCV 组(P<0.01)，PRV组与PCV组相比差异无显著性；在不同吸呼比，TGI(2∶1)组PIP显著高于TGI(1∶2)组(P<0.01)；TGI组及PRV组PaCO₂ 较PCV组明显下降，TGI组较PRV组下降更明显；PaO₂ 、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CTGI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，PRV为安全使用CTGI提供了保证。

    

ZHAN Qingyuan, WANG Chen, SHANG Mingyu

Beijing Institute of Respiratory Medicine, Beijing Red Cross Chaoyang Hospital-Affiliate of Capital University of Medical Sciences, Beijing 100020

【Abstract 】 Objective Toestablish the method of continuous tracheal gas insufflation (CTGI) and investigate therole 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 mechanicallyventilated by using Evita 2 (Drager Inc.). PRV was inserted into the ventilatory circuitfor selected experiment steps and adjusted a threshold pressure equal to the presetinspiratoy pressure. PCV, PCV+CTGI (TGI group) and PCV+CTGI+PRV (PRV group) were conductedin different inspiration/expiration (I/E) ratio of 1∶2 and 2∶1. Gas exchange, lungmechanics and hemodynamics status were monitored at the constant set inspiratoy pressureof PCV. Results At the same I/E ratio, peak airway pressure in TGI group was higher thanthat of PRV and PCV group (P<0.01), whereas PRV group maintained the preset inspiratorypressure 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). PaCO₂ in TGI andPRV group decreased significantly than that of PCV, TGI group was more lower than PRVgroup. PaO₂ , hemodynamics and oxygenation remained unchanged in all groups.Conclusions The CTGI device is effective in improving alveolar ventilation with nosignificant influence on hemodynamics and oxygenation; A pressure relief valve isnecessary to ensure the safe use of CTGI.

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