Base deficit in the immediate postoperative period of open-heart surgery and patient outcome

Abstarct Background: Base deficit is a non-respiratory indicator of acid base status that evaluates the severity of shock at the cellular level. Base deficit results from cellular metabolism of pyruvate under anaerobic conditions. In this situation, base deficit is a sensitive marker of the magnitude of anaerobic metabolism and tissue oxygen deficit [1]. Several studies have shown a strong positive correlation between base deficit and the risk of morbidity and mortality in clinical situations such as circulatory shock, extracorporeal support and in children after operation for complex congenital heart disease. Methods: 136 consecutive cases with coronary artery disease and valvular heart disease were scheduled in the study. 20 variables were determined during the preoperative, intraoperative and postoperative periods. Statistical univariate analysis was performed differentiating patients whose initial base deficit after weaning from cardiopulmonary bypass was -8 meq and these whose base deficit was equal or more than -8 meq. Results: 39 patients had base deficit levels less than -8 (Group A) and 91 had a level of >_ -8 meq/L (Group B). Patients with a base deficit level of -8 meq/L or more were older and most of them were women. The prevalence of left ventricular ejection fraction less than 30% and coronary artery disease was not significantly higher in patients with base deficit of >_ -8 meq/L . No difference was found according to the presence of hypertension or diabetes in patients with base deficit levels of –8 or higher than in those with base deficit levels less than –8 (P >0.05). In the univariate analysis of preoperative variables, there were no differences with respect to factors such as age, sex, diabetes, preoperative hemoglobin level, hypertension, emergency operation and redo operation. Congestive heart failure was different between the two groups (P < 0.05). Three variables had a statistically significant difference in the univariate analysis and two of them were highlighted by the linear logistic model. Conclusion: The value of base deficit which was measured during the immediate postoperative open-heart surgery period is correlated with the volume of fresh frozen plasma and blood transfusion after open heart surgery and using of intra-aortic balloon pump after surgery.