【摘要】 目的　观察不同气道压及气流量对连续气流通气 ( CFV)犬气体交换的影响。方法　选用健康杂种犬 9只 ,在全麻肌松下 ,以较低气道正压 ( Paw为 3 cm H2 O)三种不同气流量 ( 0 .6L· kg- 1· min- 1 ,0 .8L· kg- 1· m in- 1 ,1.0 L· kg- 1· min- 1 )进行 CFV,并与间歇正压通气 ( IPPV)及气道压为 0 cm H2 O时不同气流量 CFV相比较。每种通气方式维持 3 0分钟后抽取股动脉血 ,肺动脉血即混合静脉血作血气分析 ,并根据标准分流公式计算肺内分流率。结果　 CFV各组均能维持 Pa CO2 在正常范围。气道压为 3 cm H2 O时 ,各流量组均能维持 Pa CO2 在正常生理范围 ,且 Pa CO2 随气体流量加大而降低 ,Pa CO2 及 Q.s/ Q.t均显著低于气道压为 0 cm H2 O时对应值 ( P<0 .0 5 )。结论　 CFV时 ,维持较低气道正压能维持有效肺气体交换 ,通气流量大小与 Pa CO2 有较密切关系更多还原

【Abstract】 Objective To evaluate the effects of different airway pressures and flow rates on gas exchange during constant flow ventilation(CFV) in dogs.Methods A lower airway pressure of 3cmH 2O and three gas flow rates(0.6L·kg -1 ·min -1 ,0.8L·kg -1 ·min -1 ,1 0L·kg -1 ·min -1 )were used during CFV in nine anesthetized and paralyzed dogs.After 30 min of each CFV mode,arterial blood gases and mixed venous blood gases were measured.Intrapulmonary shunt(Q s/Q t) was calculated from the measured data.The parameters measured above were compared with those of CFV at 0 cmH 2O of airway pressure(Paw) and those of intermmitent positive pressure ventilation(IPPV).Results PaCO 2 was maintained in the normal range at three CFV flow rates.PaCO 2 decreased with the increase of flow rate.Compared with those at Paw 0 cmH 2O,PaCO 2 and Q s/Q t significantly decreased at Paw 3cmH 2O(P<0 05) Conclusion A lower positive airway pressure and lower flow rate contribute to maintain adequate lung gas exchange and decrease intrapulmonary shunt to a certain extent during CFV.更多还原