胎粪吸入性肺炎应用常频与高频通气的研究

目的　 评估常频通气和高频通气治疗胎粪吸入性肺炎 (MAS)所致呼吸衰竭的临床与实验对比疗效。 方法 　实验方面 :健康白兔 ,气管注入胎粪混悬液 ( 3～ 5ml/kg) ,呼吸衰竭模型出现后随机分组 :①继续常频通气 (CMV) 3h后转为高频通气 (HFV) 3h(CMV HFV组 ) ;②转为HFV 3h后再转为CMV 3h(HFV CMV组 )。 2 0例MAS患儿入院后即用CMV治疗 ,当所用吸入氧浓度 (FiO2 ) >0 82h左右 ,经皮氧饱和度 (TcPO2 )仍 <90 %,改为HFV治疗 ;当FiO2 >0 82h左右 ,TcPO2 能维持在90 %以上 ,继续用CMV治疗。 10例继续应用CMV治疗 ,10例改用HFV治疗。 结果 　动物出现呼吸衰竭模型时 ( 0h)的氧合指数 (OI)二组无差异 ,CMV HFV组在治疗后 3hOI无明显变化 ,至 6hOI有上升 ;HFV CMV组治疗后 3hOI较 0h时有下降 ,两组动物治疗后 3h的OI的组间比较有差异。 2 0例患儿中 ,CMV组治愈 7例 ,死亡 2例 ,放弃 1例 ;HFV组治愈 7例 ,放弃 2例 ,死亡1例。HFV组患儿治疗后 1hOI较 0h有下降 ,至治疗后 6h ,OI与 0h比较差异显著 ;CMV组治疗后 1hOI有明显下降 ,但至治疗后 6h下降幅度不明显。二组患儿的呼吸机应用时间和用氧时间均无差异。 结论 　MAS用HFV治疗后的氧合作用较CMV改善明显和吸入氧浓度下降迅速

Comparing study of high frequency ventilation and conventional ventilation in meconium aspirated syndrome

Objective To compare the efficacy of high frequency ventilation (HFV) and conventional ventilation (CMV) both in animal model and in clinical patients with respiratory failure induced by meconium aspirated syndrome (MAS).Methods Experiment:White rabbits were tracheotomized,cannulated and ventilated mechanically.The ventilated rabbits were instilled intratracheally with meconium suspension resulting in respiratory failure as evidenced by more than 50% reduction of dynamic lung compliance (Cdyn) and increase in mean oxygenation index (OI) or decreased PaO\-2 less than 75 mmHg.The animals were then allocated to two groups.In each group the animals were initially ventilated with CMV or HFV mode for 3 h and then in a crossover fashion with HFV or CMV for another 3 h respectively (CMV HFV,HFV CMV).Clinical observations 20 patients diagnosed MAS and needed CMV were enrolled in this study.Patients who failed to maintain TcPO\-2>90% when FiO\-2>0.8 with 2 hs were changed to HFV.Results There was no OI difference between two animal groups when respiratory failure occured. In the first 3 h of treatment,HFV CMV group had significantly reduced OI compared with 0 h ,while in CMV HFV groups hadn't reduced OI compared with 0 h;There had be significantly difference in OI between two animal groups after 3 h treatment.There were 10 neonates changed to HFV treatment.After 1 h treatment,the OI of HFV group was decreased rapidly compared with 0 h, but no significantly difference.After 6 h treatment,the OI of HFV decreased significantly.Conclusion Compared with the CMV,HFV can rapidly reduce OI,also HFV rapidly decreased FiO\-2 of MAS in clinical and animal study.