Whole Body Oxygen Delivery and Consumption During Cardiopulmonary Bypass Surgery

Cardiopulmonary bypass (CPB) is a technique used to maintain adequate perfusion when the heart has been stopped. The technique is often utilized in coronary artery bypass graft (CABG) surgery where patients are often cooled in order to slow metabolism and reduce oxygen demand. In this study, measurements of the oxygen delivery and consumption during surgery were made from 12 patients to investigate the extent of hypothermic protection. During hypothermia, oxygen consumption was significantly reduced by an average of 43%, P < 0.003. During short intentional periods of reduced flow, and hence oxygen delivery, an oxygen debt was accrued which caused a period of increased oxygen consumption on resumption of full flow. During hypothermic CPB this oxygen repayment was 101 ± 8% and in normothermia was 78 ± 6% of the accrued debt. © 2012 Springer Science+Business Media, LLC.