高频-常频程序喷射通气时喷射导管前端位置对血二氧化碳清除效果的影响

The effect of different positions of injector catheter tip on carbon dioxide elimination during high-con-ventional frequency jet ventilation

目的:比较气道内不同位置施行高频-常频程序喷射通气清除血CO2的效果。方法:择期非气腹、非胸科手术患者20例,全麻后术中行高频-常频程序喷射通气,将实验对象随机分为A、B组,A组先将喷射导管前端置于隆突上3 cm施行高频-常频程序喷射通气40 min;再将喷射导管前端置于声门水平行高频-常频程序喷射通气,施行喷射通气40 min后改为间歇正压通气至术毕;B组除喷射导管前端放置顺序与A组相反,其他均同A组。记录喷射通气前(T0)、喷射通气20 min(T_1)、喷射通气40 min(T_2)3个时间点的呼气末CO2分压(P_(ET)CO_2)、吸气峰压(PIP)、平均动脉压(MAP)、心率(HR)、脉搏氧饱和度(Sp O2)和血气分析指标。结果:隆突上喷射通气时,P_(ET)CO_2在T_1、T_2时均显著高于T0时,T_2时显著高于T_1时,差异均有统计学意义(P<0.05);声门喷射通气时,P_(ET)CO_2在T_1、T_2时均显著低于T0时,差异有统计学意义(P<0.05);2组喷射通气位置先后顺序比较的血气指标差值d-Pa CO2、d-Pa O2、d-p H、d-HCO3-差异均无统计学意义(均P>0.05);2组喷射通气部位比较的d-Pa CO2、d-p H、d-HCO3-差异均有统计学意义(均P<0.01)。结论:高频-常频程序喷射通气时,声门水平喷射通气清除血CO2效果更好,而喷射导管头端置于隆突上3 cm处则有血CO2升高。

Objective： To compare the effect of carbon dioxide elimination during high-conventional frequency jet ventilation with different injector positions in trachea. Methods： Twenty patients undergoing scheduled surgery were selected in this study, with exclusion of thoracic or laparoscopic surgery. High-conventional frequency jet ventilation was applied after general anesthesia. The study objects were randomly divided into two groups named group A and group B by crossover design. In group A, the injection catheter tip was first placed in the endotracheal tube about 3 cm above carina for 40 minutes applying high-conventional frequency jet ventilation, then the injection catheter tip was placed proximal to vocal cord level for another 40 minutes for the same. After that, IPPV was carried out to the end of the surgery. In group B, the only difference is that the injection catheter tip placement sequence was opposite to group A. P_（ET）CO_2, PIP, MAP, HR, SpO_2 and the results of blood gas analysis were recorded at three defined time points including the time before jet ventilation（T0）, 20 minutes after jet ventilation（T_1）, 40 minutes after jet ventilation（T_2）. Results： The value of P_（ET）CO_2 at T_2 and T_1 was significantly higher than that at T0（P〈0.05）, and the value at T_2 was significantly higher than that at T_1（P〈0.05） when the injector head was placed about 3 cm above carina. While the value of P_（ET）CO_2 at T_2 and T_1 was significantly lower than that at T0（P〈0.05） when the injector tip was located proximal to the vocal cord level. Placement sequences of injection catheter tip in these two groups made no statistical differences in values of d-PaCO_2（P〉0.05）, dPaO2_（P〉0.05）, d-PH（P〉0.05）, d-HCO_3-（P〉0.05）. However, there were significant differences in d-PaCO_2 （P〈0.01）, d-PH（P〈0.01）, d-HCO_3-（P〈0.01）. Conclusion： It is easier to eliminate carbon dioxide in blood when the injector tip was located proximal to the vocal cord level than that was placed about 3 cm above carina where the level of carbon dioxide in blood increased during the high-conventional frequency jet ventilation.