PROLONGED REWARMING AFTER HYPOTHERMIC CARDIOPULMONARY BYPASS DOES NOTATTENUATE REDUCTION OF JUGULAR BULB OXYGEN-SATURATION

Objective: This study investigates the effects of rapid versus graded rewarming on decreases in jugular bulb oxygen saturation (SjO(2)) duri ng cardiopulmonary bypass (CPB) in a prospective nonrandomized and non blinded design. Setting and Participants: At the Department of Anesthe siology (University Hospital Eppendorf, Germany), 28 patients (ASA III ) undergoing coronary artery bypass graft were investigated. Intervent ion: CPB was managed according to alpha-stat conditions during moderat e hypothermia (27 degrees C). In group 1 (n = 17), rewarming was perfo rmed by increasing the perfusate temperature to 36 degrees C within 7 minutes, in group 2 (n = 11) within 15 minutes. Measurements and Main Results: SjO(2) was measured by a fiberoptic catheter placed in the ri ght jugular bulb. Data were recorded before and 40 minutes after the s tart of rewarming every 5 minutes. During rewarming of CPB, SjO(2) was decreased to 43 +/- 7% in group 1 and to 44 +/- 4% in group 2. In gro ups 1 and 2, the maximum reduction of SjO(2) occurred 17 minutes and 3 0 minutes after start of rewarming, respectively. The delayed reductio n of SjO(2) in group 2 correlated strongly with the prolonged increase in jugular bulb temperature. Conclusion: The current data show that s low rewarming does not attenuate reductions of SjO(2). This suggests t hat the reduction of SjO(2) during rewarming of CPB is not a function of the rewarming speed but is strongly correlated with the increase in jugular bulb temperature, with a maximum effect just before reaching normothermia of the brain. Copyright (C) 1997 by W.B. Saunders Company .