高频振荡通气联合肺表面活性物质治疗吸入性肺损伤并急性呼吸衰竭的实验研究

目的 探讨高频振荡通气（HFOV）和常规机械通气（CMV）及其联合肺表面活性物质（IS）对重度蒸汽吸入性肺损伤并呼吸衰竭的治疗效果。方法 新西兰大白兔37只制成重度蒸汽吸入性肺损伤并呼吸衰竭模型，随机分为五组，采用四种方法进行通气治疗（CMV，HFOV，CMV＋PS及HFOV＋PS），分别在治疗后1，2，3及4h取动脉血行血气分析。治疗4h后处死动物，取右肺下叶称重后，计算湿质量／干质量比值（W／D）；右肺中叶4个不同部位（依赖区和非依赖区）取标本，行病理学检查。对照组不行机械通气。结果 伤后PaO2均降至60mmHg以下，各组伤前、伤后组内比较均有显著性差异（P〈0．01），各组PaCO2伤前、伤后组间比较均无显著性差异（P〉0．05）。4个治疗组的PaO2均在通气治疗1h后明显上升。通气治疗4h内PaO2维持在良好水平。HFOV组和HFOV＋PS组的PaO2分别高于CMV组和CMV＋PS组（P〈0．01，P〈0．05）；CMV＋PS组在伤后2h。HFOV＋PS组在伤后2和3h，PaO2明显优于相应未加PS组（P〈0．05）。肺泡气．动脉血氧分压差P（A-a）O2]在HFOV组和HFOV＋PS组分别低于CMV组和CMV＋PS组（P〈0．01，P〈0．05）；CMV＋PS组和HFOV＋PS组在治疗2，3及4h，P（A-a）O2均分别显著低于CMV组和HFOV组（P〈0．05）。4个治疗组伤后各时点的PaCO2均无明显变化（P均〉0．05）；伤前、伤后各时点的动脉压和中心静脉压也无明显变化（P均〉0．05）。肺组织W／D在HFOV和CMV组，HFOV＋PS组和CMV＋PS组间比较均无显著性差异（P均〉0．05）；加用PS组与相应未加PS组比较有显著性差异（P〈0．05）。肺组织病理学检查发现HFOV组的损伤程度较CMV组明显减轻，HFOV＋PS组损伤最轻，CMV组损伤最重。结论 HFOV联合PS能提高蒸汽吸入性损伤兔的Pa02，减轻肺损伤。且对循环功能无不良影响，是治疗吸入性损伤并呼吸衰竭较好的方法。

Experimental study of high frequency oscillatory ventilation combined with exogenous pulmonary surfactant for the treatment of acute lung injury with acute respiratory failure induced by vapour inhalation

Objective To compare the effects of high frequency oscillatory ventilation (HFOV) and conventional mechanical ventilation (CMV) with or without pulmonary surfactant(PS) supplement on water vapour inhalation injury.Methods New Zealand rabbits model of severe acute lung injury with acute respiratory failure caused by steam inhalation was established.Then the animals were treated by CMV,HFOV,CMV+PS or HFOV+PS,respectively while animals in control group were not ventilated and supplemented with PS.Femoral arterial blood samples were obtained at 1,2,3,4 h after treatment for blood gas analysis.4 h after treatment, the lowest lobe of right lung was weighed for calculating wet-to-dry weight ratio (W/D).Four different parts including dependent areas and non-dependent areas of the middle lobe of right lung were excised for histological observation.Results (A) After ALI established PaO_2 in the five groups decreased below 60 mm Hg (P<0.01),and intergroup differences were not found(P>0.05).Meanwhile the change of PaCO_2 showd no statistical significance(P>0.05).(B) PaO_2 in the four treatment groups had increased since one hour after treatment and sustained at favorite levels during treatment period.PaO_2 in the HFOV and HFOV+PS groups were higher than those in CMV and CMV+PS groups,respectively (P<0.01,P<0.05).PaO_2 in the CMV+PS group at 2 h and HFOV+PS group at 2 h and 3 h were significantly higher than those in corresponding non-PS groups at the same timepoints (P<0.05).P_ (A-a) O_2 in the HFOV and HFOV+PS groups were lower than those in CMV and CMV+PS groups (P<0.05).P_ (A-a) O_2 in the two groups with PS at 2 h,3 h and 4 h t were statistically lower than those in the two corresponding groups without PS (P<0.05).The pH and PaCO_2 as well as circulatory function in the four groups were not significantly different at different treatment timepoints (P>0.05).(C) Lung W/D was not different between CMV and HFOV groups (P>0.05),or CMV+PS and HFOV+PS groups.But lung W/D in the two groups treated with PS showed statistically decrement than that in non-PS groups (P<0.05).(D) Histological injury score was lowest in HFOV+PS group and highest in CMV group.Conclusion HFOV combined with exogenous PS supplement can improve arterial oxygenation and alleviate pulmonary edema and injury,which may be a optimal method for the treatment of acute lung injury with acute respiratory failure caused by water vapour inhalation.