Duration of Hypothermia, Rewarming Rate and Temperature Influence Surgical Outcomes for On-Pump Coronary Artery Bypass Grafting

Objectives: Temperature management during cardiopulmonary bypass (CPB) has an established influence on surgical outcomes. The purpose of this study was to examine the relationship of the minimum temperature, duration of hypothermia, rewarming rate and peak rewarming temperature to post-surgical outcomes. Methods: Analysis of 2259 patients undergoing isolated on-pump CABG. Outcomes included 30day mortality, myocardial infarction, stroke, infection, prolonged ventilation, renal failure, return to theatre, 24-hour blood loss and post-operative length of stay. Regression analyses were used to compare temperature management with outcomes. Results: Higher rewarming temperatures were associated with increased mortality, myocardial infarction and 24-hour blood loss; longer duration of temperatures below 34°C with increased 24hour blood loss; and faster rewarming rates with increased incidence of stroke and 24-hour blood loss. Conclusions: Rewarming temperature and rate, and the duration of temperature <34°C should be limited to reduce the incidence of adverse outcomes.