吸入一氧化氮对婴幼儿体外循环中肺功能及其超微结构的影响

目的探讨吸入一氧化氮（NO）对婴幼儿体外循环（CPB）中肺功能及其超微结构的影响。方法将30例患室间隔缺损的婴幼儿随机分为对照组和NO组,NO组在CPB期间吸入40×10^-6mg/L NO直至关胸。CPB前和术后气管插管未拔前0-1 h,〉1-2 h,〉3-4 h测定气道压、吸入氧浓度和呼气末二氧化碳浓度（ET CO2）,并分别在同时点采动脉血进行血气分析,计算肺泡死腔率（VD/VT）,肺泡动脉血氧分压差P（A-a）O2]、动脉血氧含量（CaO2）和肺泡氧合指数（OI）;记录术后呼吸机支持时间,并行肺组织超微结构的观察。结果与对照组比较,NO组VD/VT、P（A-a）O2、OI明显下降（P〈0.05）,CaO2升高（P〈0.05）;肺组织超微结构显示炎症水肿明显减轻。结论婴幼儿CPB术中存在明显肺损害,表现为一些亚临床性肺功能损伤。吸入40×10^-6mg/L NO对CPB期间肺功能有保护作用。

Effects of Inhaled Nitric Oxide on Pulmonary Function and Ultrastructure during Cardiopulmonary Bypass in Infants

Objective To explore the effects of inhaled nitric oxide（NO） on pulmonary function and ultrastructure during cardiopulmonary bypass（CPB）in infants. Methods Thirty infants with ventricular septal defect were randomly divided into two groups： control group（n=15） and NO group（n=15）.The cases of NO group kept inhaling 40×10^-6mg/L NO until the sternum closure.Before CPB and 0～1 h,〉1～2 h,〉3～4 h before postoperative extubation,the mean pulmonary airway pressure,fraction of inspired oxygen（FiO2）,end-tidal CO2（ET-C02）, arterial blood gas, value of volume of dead air space/tidal volume （VD/VT）, alveolar-arterial PO2 difference P （A-a）O2], arterial mooa oxygen cull （CaO2）, and oxygenation index （OI）were detected to evaluate pulmonary function. The time of mechanical ventilation was recorded, and pulmonary tissue cut to observe the changes ultrastructural. Results The VD/VT, ,P（A-a）O2 and OI in control group were much higher than those in NO group after reperfusion while the CaO2 was lower than that in NO group. Uhrastructural changes indicated that pulmonary edema in NO group was less severe than that in control group. Conclusion Cardiopulmonary bypass in infants leads to obvious lung injury with sub-clinical manifestations. Inhaled 40 × 10^-6mg/L NO has protective effects on lung function during CPB for infants.