死腔内气体吸出技术对急性高碳酸血症犬呼吸功能及血流动力学的影响

Effects of aspiration of airway dead space on blood gases and respiratory mechanics in acute hypercapnia model dogs

目的 建立死腔内气体吸出技术 (ASPIDS)的方法 ,并探讨ASPIDS对急性高碳酸血症(HC)杂种犬二氧化碳清除的效果及其对通气效率的改善作用。方法 将 12只杂种犬分为常规机械通气 (CMV)组和高碳酸血症 (HC)组 ,每组 6只。用自行设计的ASPIDS装置对两组动物行气管内吹气(TGI)和ASPIDS ,分别观察两组动物在TGI(吹气流量 4 0L min)和ASPIDS(抽气流量 4 0L min)时呼气末二氧化碳分压 (PetCO2 )、血气、呼吸力学、血流动力学等指标的变化。结果 (1)ASPIDS可明显降低两组动物的动脉血二氧化碳分压 (PaCO2 )水平 (P <0 0 0 0 1) ,并能在潮气量 (VT)降低 30 %的情况下维持PaCO2 在正常范围 ,ASPIDS对二氧化碳的清除效果优于TGI;(2 )ASPIDS使两组动物的气道压力明显降低 (P <0 0 0 0 1) ;(3)ASPIDS使PetCO2 和呼气阻力 (Re)显著降低 ,而对肺顺应性 (Cst)无明显影响(P >0 0 5 ) ;(4 )ASPIDS对血流动力学和氧动力学指标无显著影响 (P >0 0 5 )。结论 ASPIDS是一种简便实用的机械通气的辅助手段 ,较TGI更能有效地降低PaCO2 。

Objective To establish the method of aspiration of airway dead space (ASPIDS) and evaluate the effects of ASPIDS on elimination of CO 2 and improvement of ventilation efficiency Methods Using self designed ASPIDS device, physiological parameters such as PaCO 2,P peak ,P pause ,end expiratory carbondioxide pressure (P et CO 2), lung statistic compliance (Cst), respiratory resistance (Re) and hemodynamics in two animal groups of conventional mechanical ventilation (CMV) and hypercapnia (HC) were observed by applying tracheal gas insufflation (TGI 4 0 L/min) and ASPIDS (4 0 L/min) Results ASPIDS significantly decreased PaCO 2 level , enhanced CO 2 elimination and maintained PaCO 2 in normal range while decreased V T by 30%, the elimination of CO 2 of ASPIDS was superior to that of TGI ASPIDS significantly decreased airway pressure in both animal groups P et CO 2 and Re levels significantly decreased after ASPIDS ASPIDS showed no influence on Cst , hemodynamics and oxygenation Conclusions The ASPIDS device is a simple and practical adjunct method to mechanical ventilation, it can more effectively decrease PaCO 2 than TGI, and maintain lower airway pressure