急性肺损伤时胃黏膜pH值和肺微循环相关性研究

目的 探讨急性肺损伤(acute lung injury,ALI)时胃黏膜pH值(gastric intramucosal pH,pHi)与肺微循环的相关性. 方法 健康家兔24只,体重2.6～3.2 kg,采用随机数字表法分为3组(每组8只):对照组(C组)、模型组(M组)和治疗组(T组).麻醉稳定后30 min (T0),M组和T组制备兔ALI模型,模型制备成功后(T1),T组静脉输注前列腺素E1(prostaglandin E1,PGE1)30 ng·kg-1· min-1.分别于T0、T1及模型成功后30 min(T2)、60 min(T3)、90min(T4)、120min(T5)、150min(T6)、180min(T7),记录平均肺动脉压(mean pulmonary artery pressure,MPAP)、动脉血氧分压(pressure of artery oxygen,PaO2)、气道峰压(peakinspiratory pressure,PIP)及测量肺微循环和pHi.T7时记录支气管肺泡灌洗液(bronchoalveolar lavage fluid,BALF)中中性粒细胞(polymorphonuclear neutrophils,PMN)及总细胞计数,计算肺湿/干重比(wet/dry,W/D).应用线性混合效应模型分析肺微循环和pHi的相关性. 结果 与C组比较,M组与T组T1～T7时PaO2降低,MPAP及PIP升高(P＜0.05);M组和T组BALF中PMN百分比和肺W/D升高(P＜0.05);M组T2～T7时pHi降低,T3～T7肺微循环血流量减少(P＜0.05).与M组比较,T组T3～T7时PaO2升高,T4～T7时PIP降低,T5～T7时MPAP降低(P＜0.05);T组BALF中PMN百分比(20.341±0.033)比(40.232±0.054)]和肺W/D(0.191±0.020)比(0.472±0.061)]降低(P＜0.05),T2～T7时pHi升高,T3～T7肺微循环血流量增加(P＜0.05).C组、M组和T组肺微循环的变化与pHi的变化相关(P＜0.05). 结论 随着肺损伤的产生和改善,肺微循环和pHi也发生相应的改变,二者具有相关性,可以通过pHi来预测肺损伤的情况.

The correlation study between gastric intramucosal pH and pulmonary blood flow during acute lung injury

Objective To investigate the correlation between gastric intramucosal pH(pHi) and pulmonary blood flow during acute lung injury(ALI).Methods Twenty-four healthy male rabbits weighing 2.6-3.2 kg were randomly divided into 3 groups(n=8):rabbits without any treatment(group C),rabbits with ALl(group M) and rabbits with ALI and Prostaglandin treatment(group T).After 30 min stabilization (T0),oleic acid 0.015 ml/kg was injected intravenouslyin group M and group T.ALI model was successful (T1).prostaglandin E1 (PGE0 was then continuously infused iv at 30 ng·kg-1 ·min-1 Mean pulmonary artery pressure (MPAP),pressure of artery oxygen(PaO2),peak inspiratory pressure(PIP),lung blood flow (measured with Doppler laser flow meter) and pHi (measured with Datex-EngstromTonocap) at T0,T1 and 30,60,90,120,150 min and 180 min after ALI models were established (T2-T7).The animals were killed at T7 by exsanguination and the lungs were removed for lung wet/dry (W/D).The right lung was lavaged and bronchoalveolar lavage fluid (BALF) was collected for determination of total number of cells and the percentage of PMN.Investigate the correlation between the pulmonary microcirculation and the pHi with linear mixed effect model.Results Compared with group C,PaO2 levels were decreased while MPAP and PIP were increased at T1-T7 in group M and group T (P＜0.05),the percentage of PMN in BALF and the ratio of lung W/D were increased in group M and group T(P＜0.05),the pHi at T2-T7 and the microcirculation of lung at T3-T7 were lower in group M (P＜0.05).Compared with group M,the PaO2 was incrcased at T3-T7 while the PIP and the MPAP was decreased at T4-T7 and at T5-T7 respectively in group T(P＜0.05),the percentage of PMN in BALF (20.341±0.033) vs (40.232±0.054)] and the ratio of lung W/D (0.191±0.020) vs (0.472±0.061)] were decreased in group T (P＜0.05).The pHi at T2-T7 and the microcirculation of lung at T3-T7 were higher in group T (P＜0.05).The pHi and the pulmonary blood flow have the positive correlation in group C,group M and group T(P＜0.05).Conclusioas The pHi and pulmonary blood flow relatively changed during the ALI deterioration and amelioration.The pHi and the pulmonary blood flow have the positive conrelation.We can predict the status of ALI through detection of pHi.