应用高频通气和吸入一氧化氮治疗实验性胎粪吸入

Effects of high frequency ventilation and inhaled nitric oxide in rabbits with meconium aspiration

目的 :评价实验性胎粪吸入 (MAS)联合应用吸入一氧化氮 (iNO)和高频通气(HFV)或常频通气 (CMV)的治疗效果。方法 :新西兰白兔气管切开插管常频机械通气 ,气道内滴入胎粪 3～ 4ml/kg约 30min后出现MAS模型 ,表现为肺顺应性 (Cdyn)下降 >30 % ,动脉血氧分压 (PaO2 ) <10kPa,随机分为对照组 (机械通气 )和治疗组 (机械通气 +iNO) ,每组中先用CMV 3h后改HFV 3h (CMV -HFV) ,或先用HFV 3h后改CMV 3h (HFV -CMV)。结果 :在治疗开始的 3h ,对照组HFV -CMV和治疗组HFV -CMV以及CMV -HFV的氧合指数 (OI)均有显著下降 (P<0 0 5 ) ,在继续治疗的 3h (6h) ,对照组CMV -HFV的OI无任何改善 ,对照组HFV -CMV的OI明显恶化 (P>0 0 5 ) ,而治疗组CMV -HFV和HFV -CMV的OI较治疗前均有改善 ,但无统计学意义。结论 :治疗实验性胎粪吸入联合应用iNO和CMV或iNO和HFV对早期氧合的改善较单用CMV更为有效。

Objective:To evaluate effects of inhaled nitric oxide(iNO) in experimental meconium aspiration syndrome(MAS) treated with high frequency ventilation(HFV) or conventional mechanical ventilation(CMV).Methods:10% meconium was instilled iutratracheally into ventilated adult rabbits resulting in respiratory failure as evidenced by more than 50% reduction in dynamic lung compliance(Cdyn) and increase in mean oxygenation index(OI).The animals were randomly allocated to 2 groups treated with or without iNO at 20ppm.In each group the animals were initially ventilated with either CMV or HFV mode for 3h and then crossed over to receive HFV or CMV for another 3h (CMV-HFV,HFV-CMV),respectively.Results :In the first 3h treatment the animals subjected to HFV-CMV in the control groap,and those with both HFV-CMV and CMV-HFV in the iNO group had significantly reduced OI(P<0 05).In the subsequent 3h,the animals in the control group with CMV-HFV didnt improve in OI and those with HFV-CMV deteriorated markedly ,whereas for those in the iNO group with both CMV-HFV and CMV-HFV moderate improvement of OI was observed(P>0 05).Conclusion:Combined treatment using iNO with either CMV or HFV was more effective in improving blood oxygenation than using CMV alone in this animal model.