抗坏血酸在体外循环中对肺的保护作用

The Protective Effects of Ascorbic Acid on Lung during Cardiopulmonary Bypass

目的研究抗坏血酸对体外循环(CPB)所致肺损伤的保护作用。方法选择心脏瓣膜置换术且腔静脉阻断时间≥60min的患者50例,采用随机双盲对照研究法分为两组。实验组在手术前及体外循环中分别缓慢给予抗坏血酸125mg/kg,对照组予以等体积生理盐水。两组均于手术开始时、CPB后1、3、6h查动脉血气分析,计算肺泡气-动脉血氧分压差[D(A-a)O2],呼吸指数(RI),氧合指数(OI);在上下腔静脉开放后15min分别取肺动脉、肺静脉血测定丙二醛(MDA)、超氧化物歧化酶(SOD)。结果CPB后两组D(A-a)O2、RI、OI相对于基础值增长或下降百分比差异有统计学意义(P<0.05);实验组左右心房之间MDA和SOD浓度的增长或下降百分比较对照组低(P<0.05);实验组术后拔管时间较对照组短(P<0.05)。结论抗坏血酸对体外循环所致肺损伤有保护作用。

Objective To investigate the efficacy of ascorbic acid on lung against ischemia-reperfusion injury under cardiopul- monary bypass（ CPB ）. Methods Fifty patients were randomly divided into two groups. Ascorbic acid group：ascorbic acid was injected in-travenously 10 minutes before operation and caval veins declamping（ 125mg/kg each time ）. control group：ascorbic acid was replaced by normal saline.Before operation and 1,3,6h after CPB,alveolar-arterial oxygen difference（ D（A-a）O2） ,oxygenation index（OI） and respiratory index（ RI）were measured in each group. Plasma malondialdehyde（MDA） and superoxide dismutase（SOD） levels were measured in each group at 15 minutes after caval veins declamping. Results At 3,6h after CPB,the increase percentage of D（A-a）O2 and RI and the decrease percentage of OI from baseline in ascorbic acid group were lower than those in control group（P 〈 0.05） .The increase percentage of MDA and the decrease percentage of SOD between left and right atriums in ascorbic acid group were lower than those in control group（ P 〈 0.05）.The extubation time after operation in ascorbic acid group were shorter than that in control group（ P 〈 0.05）. Conclusion Ascorbic acid had protective effect on lung induced by ischemia-reperfusion injury under CPB.