Microbubble Activity in Miniaturized and in Conventional Extracorporeal Circulation

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 (cECC). From March 2005 to June 2006, a prospective, randomized study, comparing three different mECC (MECC, PRECiSe, Resting Heart) with a cECC (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 an ultrasound Doppler system. Clinical outcome was compared by evaluating the incidence of postoperative neuropsychological dysfunction, postoperative renal dysfunction and hospitalization as well as the 30-day mortality. The highest microbubble activity was measured in all devices during the first 10 minutes of extracorporeal circulation. The amount of microbubbles was lower in the Resting Heart system (p = 0.01), equal in the MECC system (p = 0.16) and higher using the PRECiSe system as compared to the cECC (p = 0.002). The microbubble diameter did not differ between all groups (p = 0.56). Postoperative neuropsychological dysfunction (p = 0.45), renal dysfunction (p = 0.67), days of hospitalization (p = 0.27), and 30 day-mortality (p = 0.30) did not differ between all groups. A great variability in the occurrence of gaseous microemboli depending on the applied circuit exists. The Resting Heart system has lower, the MECC system an equal and the PRECiSe system depicted a higher activity in comparison to a cECC. The hypothesis about an increased risk in mECC in comparison to cECC with regard to microbubble activity is not supported by our results. ASAIO Journal 2009; 55:58-62.