|Budget Amount *help
¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1997 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1996 : ¥1,300,000 (Direct Cost : ¥1,300,000)
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.