A new minimized perfusion circuit with automatic air detection reduces micro air embolism

Aims: Minimized perfusion circuits (MPC) are criticized for insufficient air elimination. We evaluated a MPC system (ROCsafe®, Terumo, Japan) with new safety features for air detection and elimination.

Methods: Deairing capabilities of the ROCsafe®-MPC and an open extracorporeal circulation (ECC) were compared in vitro. The MPC includes a venous bubble trap and an ultrasound air detector controlling a venous occluder and the speed of the centrifugal pump. Both systems were equipped with a CAPIOX SX 18X membrane oxygenator (Terumo, Japan) and a 40µm AV6SV arterial filter (Pall, USA). During a blood flow of 4 l/min we injected 30 cc air in 30 seconds into the venous line of both systems. Injections and measurements were repeated 10 times. Air bubbles were detected during 2 minutes using an ultrasound dual channel bubble counter (Gampt, Germany). Venous measurements were located after the MPC bubble trap and the ECC hard shell reservoir, respectively. Arterial data were obtained after the arterial filters. ECC measurements were performed with reservoir blood levels of 1000 cc.

Results: With active deairing venous bubble count (>40µm) was significantly (p<0.01) reduced in the MPC (288±92) compared to ECC (9825±1881). No bubbles >250µm were detected in the MPC compared to 887±560 in the ECC. Using 40µm arterial filters, we detected no relevant air after the filter in the MPC system, but serious numbers of micro air bubbles (6518±3026) in the ECC.

Conclusions: The ROCsafe®-MPC with automatic safety features provides effective deairing. Air elimination of the new MPC is superior to conventional open ECC systems.