Microbubble activity in miniaturized and in conventional extracorporeal circulation

Aims: Ever since the establishment of miniaturized extracorporeal circulation (MECC), there has been a great controversy about a possible increased risk of gaseous microembolism as compared to conventional extracorporeal circulation (ECC). Methods: From March 2005 to June 2006, a prospective, randomized study, comparing three different miniaturized extracorporeal systems (MECC®, PRECiSe®, Resting Heart™) with a conventional extracorporeal circulation system (HL30® Maquet) was performed. Ninety-three patients undergoing elective bypass surgery were included. The amount and size of microbubbles during perfusion was detected in the arterial lines utilizing the Doppler principle (Bubblecounter BC100®). In addition, the effect of a venous bubble trap on the quantity of microbubbels was assessed. Results: The highest microbubble activity was measured in all systems during the first 10 minutes after initiation of extracorporeal circulation. The amount of microbubbles was lower in the Resting Heart-System™ (p=0.011), and higher using the PRECiSe®-System as compared to the conventional ECC (p=0.002). All systems had similar sized air bubbles with an average diameter of 0.03–0.12µm. The smallest microbubbles appeared using the Resting Heart System™ (p=ns). There was a trend towards larger microbubbles in miniaturized systems in contrast to the conventional ECC. The integration of a venous bubble trap did insignificantly reduce the activity of microbubbles. Fig. 1: Progression microbubble volume over perfusion time Conclusion: Miniaturized extracorporeal systems are as safe as conventional extracorporeal systems with regard to the occurrence of microbubbles.