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. Meth ods: Between 1985 and 1994 perioperative data of 8578 consecutive CABG operations were prospectively collected. Seven variables: gender, red o vs. primary operation, elective vs. urgent surgery, age in 4 categor ies, use of IMA, number of distal anastomoses (> 4 vs. < = 4), and car dio-pulmonary-bypass-time in four categories were entered in multivari ate 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 u p 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 oper ations had complete data. Mortality and ICU-morbidity were low. The od ds 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 rat ios for longer bypass-time-categories. Conclusion: The highly signific ant 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-p ulmonary-bypass-time on outcome reflects both problems encountered dur ing revascularisation and time-related influence of cardio-pulmonary-b ypass on the human body. When a predictive model was created, CPBT pro ved to be a good predictor of undesirable postoperative events. (C) 19 97 Elsevier Science B.V.