Experimental study of extracorporeal lung assist in rat

采用微型膜式氧合器(Mini-ECLA系统)研究了V-V和V-A体外循环肺辅助(ECLA)的效果。Wistar大鼠采用全麻，腹腔注射戊巴比妥钠(50 mg/kg)，气管切开通气法。V-V和V-A ECLA分别用6Fr.Atom导管和18G Instite导管经右心房置管引流，用24G Therflow导管分别经股静脉和颈总动脉回流。我们使用的是为大鼠研制的微型致密膜中空纤维氧合器(预充量为4ml)。迷你ECLA电路的预充量为20毫升，V-A ECLA最长维持时间为150分钟(平均持续时间：83(]sy.+-)。[)61min)，获得旁路流量35.0(SY+-)。[)3.3ml/kg/min(平均值(]SY+-)。[)SD)。氧合器进、出口血气分析表明，氧合器具有较高的氧合能力和较高的CO&lt；ECLA启动后5min的血红蛋白、血浆蛋白浓度和红细胞压积分别为6.8g/dl、4.0g/dl和18.3%，在ECLA期间保持稳定。与ECLA前相比，由于大鼠较大的预充量进行了血液稀释，ECLA中出现了高钾血症。此外，V-A ECLA中出现的高钾血症可能是由于滚轮泵的溶血作用所致，而其他电解质的变化不明显。在未来的工作中，我们需要构建更小的电路来防止血液稀释和改善引流，以避免ECLA过程中因溶血而导致的高钾血症。这种微型ECLA系统可以延长大鼠的ECLA作用时间，并可能有助于体外循环效果的研究。

We investigated the effects of V-V and V-A bypass extracorporeal lung assist (ECLA) using a miniature membrane oxygenators (Mini-ECLA system) in rats. Wistar rats underwent general anesthesia with intraperitoneal pentobarbital administration (50 mg/kg) and tracheostomy for ventilation. V-V and V-A ECLA were carried out through the right atrium via a jugular vein using a 6 Fr.Atom catheter or 18 G Instite catheter for drainage, respectively, and return flow through the femoral vein or common carotid artery, respectively, using a 24G Therflow catheter. We used a miniature dense-membrane, hollow-fiber oxygenator which was developed for rat (priming volume 4 ml). Total priming volume in mini-ECLA circuits was 20 ml.We maintained the V-A ECLA for a maximum of 150 min (mean duration : 83(]SY.+-。[)61 min) and obtained bypass flow of 35.0(]SY.+-。[)3.3 ml/kg/min (mean(]SY.+-。[)SD). Analysis of blood gases between inlet and outlet of the oxygenator revealed that high oxygenation and CO<@D22@>D2 removal were obtained in the oxygenator ; gas exchange was well maintained during ECLA.The values of hemoglobin, plasma protein concentration and hematocrit at 5 min after ECLA start were 6.8 g/dl, 4.0 g/dl and 18.3 %, respectively, and were stable during the ECLA.The values were significantly decreased compared to the pre-ECLA values due to hemodilution by the relatively large priming volume for rat.Furthermore, hyperkalemia that occurred in V-A ECLA was likely due to hemolysis by the roller pump, however other electrolytes were not significantly changed. In future work we need to construct smaller circuits to prevent hemodilution and improve drainage to avoid hyperkalemia due to hemolysis during ECLA.This mini-ECLA system achieved to prolonged time on ECLA in rats and may be useful for investigation of the effects of extracorporeal circulation.