Postoperative ventilatory and circulatory effects of extended rewarming during cardiopulmonary bypass.
Postoperative effects of extended rewarming (ECR) after hypothermic cardiopulmonary bypass (CPB) were studied. All (n = 28) patients were rewarmed to a nasopharyngeal temperature exceeding 38 degrees C before terminating CPB. In 12 patients (control group) the rectal temperature (Tre) was 33.8 +/- 1.7 degrees C (mean +/- sd) at termination of CPB. In sixteen patients (ECR group) rewarming during CPB was continued to a Tre of 36.8 +/- 0.5 degrees C. Postoperative body temperatures, heat content, shivering, oxygen uptake, CO2 production and haemodynamic variables were measured. ECR reduced the heat gain required to complete core rewarming to 665 +/- 260 kJ, compared with 1037 +/- 374 kJ in the control group (p less than 0.01). The incidence of shivering was reduced (p less than 0.05) as well as shivering intensity and duration. In seven non-shivering ECR group patients this coincided with significantly reduced metabolic and ventilatory demands but these improvements were not valid for the group as a whole. The required ventilation temporarily during postoperative rewarming in both groups increased to 250 per cent of the basal need. Extending CPB rewarming (to at least 36 degrees C Tre) was inefficient when used as the sole measure to reduce the untoward effects of residual hypothermia during recovery after cardiac surgery with hypothermic CPB.
Joachimsson
P O
PO
Department of Anaesthesiology, Uppsala University, Sweden.
Nyström
S O
SO
Tydén
H
H
D000328:Adult; D000368:Aged; D002315:Cardiopulmonary Bypass; D006439:Hemodynamics; D006358:Hot Temperature / Q000627:therapeutic use*; D006801:Humans; D007036:Hypothermia, Induced; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D012119:Respiration; D012768:Shivering