Cardio-pulmonary-bypass time has important independent influence on mortality and morbidity.

OBJECTIVE To determine the influence of cardio-pulmonary-bypass-time on hospital mortality and ICU-morbidity in isolated CABG surgery. METHODS Between 1985 and 1994 perioperative data of 8578 consecutive CABG operations were prospectively collected. Seven variables: gender, redo vs. primary operation, elective vs. urgent surgery, age in 4 categories, use of IMA, number of distal anastomoses (> 4 vs. < = 4), and cardio-pulmonary-bypass-time in four categories were entered in multivariate logistic regression analysis and odds ratios for respective cardio-pulmonary-bypass-time-categories with regard to mortality, length-of-stay in the ICU and 8 ICU-complications were calculated. Bypass-time up to 90 min was the reference category, the other categories were from 1.5 to 2.5 h, 2.5 to 3.5 h, and longer than 3.5 h. RESULTS 8337 operations had complete data. Mortality and ICU-morbidity were low. The odds ratios for mortality were 2.3 (P = 0.0094), 7.4 (P < 0.0001) and 20.7 (P < 0.0001) for ascending bypass-time-categories. The odds ratios for prolonged ICU-stay were 1.8 (P = 0.0002), 3.3 (P < 0.0001) and 7.9 (P < 0.0001) for ascending bypass-time-categories. For postoperative complications the same pattern was found: consequently higher odds ratios for longer bypass-time-categories. CONCLUSION The highly significant correlation between cardio-pulmonary-bypass-time-category and the occurrence of undesirable postoperative events is demonstrated by the consequent rise in odds ratios. This independent influence of cardio-pulmonary-bypass-time on outcome reflects both problems encountered during revascularisation and time-related influence of cardio-pulmonary-bypass on the human body. When a predictive model was created, CPBT proved to be a good predictor of undesirable postoperative events.