Changes in jugular bulb oxygenation in patients undergoing warm coronary artery bypass surgery (34-37 degrees C)

Background and objective Imbalance between cerebral oxygen supply and deman d is thought to play an important role in the development of cerebral injur y during cardiac surgery with cardiopulmonary bypass. Methods We studied jugular bulb oxygen saturation, jugular bulb oxygen tens ion, arterial-jugular bulb oxygen content difference and oxygen extraction ratio in 20 patients undergoing warm coronary artery bypass surgery (34-37 degreesC) with pH-stat blood gas management. Results Only two patients showed desaturation (jugular bulb oxygen saturati on <50%) at 5 min on bypass, and none from 20 min onwards. Multiple regress ion models were performed after using bypass temperature, mean arterial pre ssure, cerebral perfusion pressure, haemoglobin concentration and arterial carbon dioxide tension as independent variables, and arterial-jugular bulb oxygen content difference, jugular bulb oxygen saturation, oxygen extractio n ratio and jugular bulb oxygen tension as individual dependent variables. Conclusions We found that jugular bulb oxygen saturation, jugular bulb oxyg en tension and oxygen extraction ratio are mainly dependent on arterial car bon dioxide tension, and arterial-jugular bulb oxygen content difference is dependent on arterial carbon dioxide tension and the bypass temperature. O ur results suggest jugular bulb oxygenation is mainly dependent on arterial carbon dioxide tension during warm cardiopulmonary bypass.