体外循环手术对小儿肺表面活性物质的影响及其与肺功能的关系

目的　探讨体外循环手术对小儿肺表面活性物质 (PS)的影响 ,以及体外循环术后PS异常和肺功能不全的关系 ,并观察外源性PS对小儿体外循环肺保护作用。方法　将 2 0例先天性心脏病室间隔缺损伴肺动脉高压并实施体外循环手术的患儿 ,随机分为对照组和用药组 (外源性PS治疗组 )。分别于术前和术后 ,检测支气管肺泡灌洗液中总磷脂、饱和卵磷脂、总蛋白的含量 ,并同步测定呼吸指数、肺动态顺应性、氧合指数及肺超微结构的改变。结果　体外循环术后PS水平显著降低 ,体外循环 6h ,用药组肺动态顺应性显著高于对照组 (P <0 .0 5 ) ,氧合指数显著低于对照组 (P <0 .0 5 )。其余时点两组无显著差异 (P <0 .0 5 )。用药组气管插管维持时间较对照组明显减少 (P<0 .0 5 ) ,但肺组织超微结构改变并无明显减轻。结论　体外循环可明显降低PS活性 ,其PS异常与呼吸功能不全密切相关。预防性应用外源性PS并不能减轻肺损伤的程度 ,但对术后出现肺功能不全有明显的保护作用

Effect of cardiopulmonary bypass on the pulmonary surfactant (PS) in children and the relationship between PS and respiratory function

Objective To elvaluate the effect of cardiopulmonary bypass (CPB) on pulmonary surfactant (PS) activity and its respiratory function, and study the protective effect of exogenous PS on respiratory insufficiency after CPB in children.Methods Twenty children of VSD associated with pulmonary hypertension undergoing heart surgery with CPB were randomly divided into two groups: control group and PS group. In control group, the bronchoalveolar lavage fluid (BALF) was obtained before and after surgery for analysing content of total phospholipid (TPL), saturate phosphatidycholine (SPC) and total protein (TP). Arterial blood was taken for gas analysis. The respiratory index (RI) was calculated. Lung dynamic compliance and oxygenate index were measured before and after opration. The intubation time of the two groups and ultrastructural change of the lung also were observed.Results In control group PS activity decreased significantly. The respiratory index was markedly increased after CPB. There was a negative correlation between PS activity and RI.After 6 hours of CPB, the dynamic compliance in the PS group was higher than that in the control group ( P <0.05),and the oxygenate index was significantly lover than that in the control group ( P <0.05). The electrical microscopy confirmed that the degree of pulmonary damage was not significantly ameliorated in the PS group.Conclusion CPB reduces pulmonary surfactant activity signifficantly. The incidence of postoperative respiratory disfunction after CPB is closely related to the reduction of PS activity. Exogenous natural PS has protective effect on respiratory insufficiency after CPB, but this is not important for the early pulmonary damage after CPB.