Perspectives for core and skin surface temperature guided extubation in patients after normothermic cardiopulmonary bypass.

Abstract

To investigate the relationship between changes in core and skin surface temperature and extubation time in patients following normothermic cardiopulmonary bypass (CPB). Prospective observational study. Intensive care unit (ICU) of a university hospital. Patients admitted to the ICU after cardiac surgery. None. Thirty-two patients undergoing cardiac surgery with the use of normothermic CPB were studied. In the ICU, urinary bladder temperature and skin surface temperature gradient (forearm temperature minus fingertip temperature) were measured at 30-min intervals for 10 h postoperatively. Every half-hour an anaesthesiologist, blinded to temperature measurements, checked the possibility of extubation. On arrival in the ICU the mean skin surface temperature gradient of the patients was 1.9+/-1.6 degrees C, indicating vasoconstriction of the dermal vessels (>0 degrees C = vasoconstriction, <0 degrees C = vasodilation) while the mean urinary bladder temperature was 36.8+/-0.4 degrees C. The change from thermoregulatory vasoconstriction to vasodilation (skin surface temperature gradient of 0 degrees C) was 137+/-49 min after arrival in the ICU. The mean time until extubation was 135+/-55 min after arrival in the ICU. There was a linear relation between a temperature gradient of 0 degrees C and extubation time, r(2)=0.49. Later, 181+/-67 min after arrival in the ICU, the urinary bladder temperature reached its maximum of 38.2+/-0.6 degrees C. This study demonstrates that the transition period from peripheral vasoconstriction to vasodilation provides an opportunity for postoperative extubation.