PHARMACOLOGICAL VASODILATATION IMPROVES EFFICIENCY OF REWARMING FROM HYPOTHERMIC CARDIOPULMONARY BYPASS

An afterdrop in core temperature after hypothermic cardiopulmonary byp ass (CPB) is related to inadequate peripheral rewarming. We proposed t hat pharmacological vasodilatation during rewarming on bypass would im prove peripheral rewarming and reduce the degree of afterdrop. Fifty-n ine of 120 patients were randomized to receive a sodium nitroprusside (SNP) infusion during the rewarming stage of hypothermic CPB. Mean sys temic vascular resistance (SVR) during the rewarming phase of CPB was 1129 dyne s(-1) cm(-5) in the control group and 768 dyne s(-1) m(-5) i n the SNP group (P less than or equal to 0.001). Patients receiving SN P rewarmed to 37.0 degrees C faster (299 min vs 376 min; P=0.003) and were extubated earlier (490 min vs 621 min; P=0.001). Patients receivi ng SNP had a warmer mean peripheral temperature (MPT) (32.9 degrees C vs 32.4 degrees C; P=0.05) on termination of CPB. Postoperative core t emperature fell less in the SNP group (35.6 degrees C vs 35.2 degrees C; P=0.01) as did MPT (31.8 degrees C vs 31.2 degrees C; P=0.004). SNP -induced vasodilatation during rewarming from hypothermic CPB improves peripheral rewarming, reduces the degree of postoperative core and pe ripheral hypothermia and reduces time to extubation.