Incidence and risk calculation of inotropic support in patients undergoing cardiac surgery with cardiopulmonary bypass using an automated anaesthesia record-keeping system

Background. This retrospective study analysed the effects of preoperative and intraoperative factors on the occurrence of inotropic support after cardiopulmonary bypass (CPB). Methods. The data sets of 1471 adult patients having received elective cardiac surgery with CPB were recorded using an online anaesthesia record-keeping system. Patients were judged to have required inotropic drug support if they had received one or a combination of the positive inotropic drugs, epinephrine, dobutamine and enoximone. The effects of age, height, weight, body mass index, gender, chronic heart failure, documented preoperative myocardial infarction, left main coronary artery disease, preoperative history of hypertension, chronic renal failure, diabetes mellitus, chronic obstructive pulmonary disease (COPD), preoperative medical treatment, type of surgical procedure, duration of CPB, duration of aortic clamping and reperfusion time were analysed by logistic regression for predictive power of the need for positive inotropic drugs. Results. Of the patients, 32.4% received positive inotropic drugs in the operating theatre after weaning from CPB. The overall 30-day mortality was 2.2%. Of non-survivors, 81.8% received inotropes compared with 18.2% of survivors (P<0.01). The numbers of previous myocardial infarctions (odds ratio (OR), 2.01), congestive heart failures New York Heart Association class >2 (OR, 1.85), COPD (OR, 1.85) and age >65 yr (OR, 1.62), aortic cross clamping time of >90 min (OR, 2.32) and coronary artery bypass surgery (OR, 0.43) all represented influential factors within the logistic regression model. Conclusion. The knowledge of these risk factors should be useful in increasing the anaesthetist's vigilance in those patients most at risk for inotropic support and in providing for more timely therapeutic intervention and optimizing anaesthesia management.