THE jOURNAL OF EXTRA-CORPOREAL TECHNOLOGY Technique Perfusion Strategies for Low-Dose and Heparin-Free Bypass

An increasing number of clinical reports are being published regarding various uses of heparin-bonded extracorporeal bypass circuits with altered coagulation regimens. Although the reasons for lowered heparinization levels have been discussed, there has been a lack of information detailing perfusion strategies necessary to manage this emerging technology. The decreased use or elimination of heparin during bypass procedures has been successfully achieved using heparin-bonded surfaces in carefully selected patients. However, if used inappropriately, the results may be catastrophic. Clotted circuits, thrombus formation and increased patient morbidity have resulted from poor circuit design and a poor understanding of the technology. Alterations in blood flow management, circuit design, cardiotomy suction, cardiac chamber venting, bypass weaning and anticoagulation management are essential for improved patient outcome. It must be stressed that "heparin-bonded" does not imply heparin-free and that any blood damage is magnified under conditions of lowered heparin levels. The risks associated with lowdose or heparin-free bypass must be carefully weighed against the potential beneftis thought to be gained from this strategy. This report summarizes our current experience, observations and perfusion techniques used in conjunction with low-dose or heparin-free extracorporeal bypass support for selected patients requiring cardiopulmonary bypass, extracorporeal cardiopulmonary support, ventricular assist devices, or extracorporeal membrane oxygenation.