180 ml and less: Cardiopulmonary bypass techniques to minimize hemodilution for neonates and small infants

Objective. To determine the efficacy of decreasing cardiopulmonary bypass ( CPB) prime volume for neonates and small infants by using low prime oxygenators, small diameter polyvinyl chloride ( PVC) tubing and removing the arterial line filter ( ALF) in an effort to reduce intraoperative exposure to multiple units of packed red blood cells ( PRBC). Methods. Two retrospective database studies comparing neonatal CPB prime volume were undertaken: Study 1 - A CPB circuit consisting of a 1/8 inch arterial line, a 3/16 inch venous line and a low prime oxygenator with 172 ml total circuit prime ( n = 74) was compared to a circuit with a 3/16 inch arterial line, a 1/ 4 inch venous line and a higher prime oxygenator with a 350 ml total circuit prime ( n = 74). Study 2 - The 172 ml circuit ( n = 389) was compared to a circuit that included an ALF and had a total circuit prime volume of 218 ml ( n = 389). Results. Study 1 of the 74 neonates and small infants whose CPB prime volume was 350 ml, 19 were exposed to two or more intraoperative exogenous PRBC units while only 3 neonates and small infants in the 172 ml prime group ( n = 74) received two or more units ( p = 0.0002). Study 2 - of the 389 neonates and small infants where an ALF was used ( prime volume 218 ml), 54 were exposed to two or more exogenous PRBC units while only 36 of the 389 patients where an ALF was not used ( prime volume 172 ml) received two or more units of intraoperative PRBCs ( p = 0.0436). Conclusion. Decreasing the neonatal and small infant extracorporeal circuit prime volume by as little as 46 ml resulted in significantly fewer multiple exposures to exogenous PRBC units.