STUDY OF RISK FACTORS ASSOCIATED DURING CARDIOPULMONARY BYPASS ON POST-OPERATIVE MECHANICAL VENTILATION DURATION IN ADULT CARDIAC SURGERY

Abstract

Background; Early extubation after cardiac surgery is feasible, also enhances ambulation, improves cardiopulmonary bypass function, and can lead to savings in health care costs. Whereas prolonged mechanical ventilation (PMV) after cardiac surgery in children is associated with a high postoperative morbidity and mortality, as well as increased ICU and hospital resource utilization. Work has been done to identify predictors of prolonged mechanical ventilation in pediatric cardiac patients however little has done to identify the predictors of PMV in adults. This study was performed to evaluate predictors of PMV in adults undergoing cardiac surgery using cardiopulmonary bypass. 

Method

We prospectively examined the role of 20 variables (preoperative: gender, BMI, weight, advanced age >60, low ejection < 25%, smoking, diabetes, hypertension Intraoperative: type of procedure, cardiopulmonary bypass time, aortic cross camp time, intra operative blood transfusions, Creatinine, use of IABP and type of cardioplegia & postoperative: pneumonia, Prolonged ICU stay and hospital mortality) in determining the period of ventilator support in 85 patients undergoing cardiac surgery using cardiopulmonary bypass technique. PMV was defined as mechanical ventilation (MV) > 24h following operation. After univariate analysis, a Multivariate logistic regression analysis was used to determine independent relationships between preoperative & perioperative factors and prolonged mechanical ventilation.

Results

Patients on average were 80% males and 20% females in Non PMV and 90.8 % males and 9.2% females in PMV group. Smoker 33%, hypertensive 49%, age >60 in 20%, & EF <25 in 4% patients in non PMV group while in PMV Smoker 0%, hypertensive 40%, age >60 in 80%, & EF <25 in 0% of patients. 10 of 85 patients required ventilator support in excess of 24 hours. Among the remaining patients the extubation was achieved early. The median duration of MV was 31.0 h in PMV, while it was 5 h in non-PMV. The independent risk factors for PMV were CPB time (p value 0.042), pneumonia (p value 0.023), hospital stay (p value 0.005), cardioplegia volume (p value 0.004) and age (p value 0.015).Conclusion The present study strongly suggests that advanced Age, prolonged cardiopulmonary bypass time, cardioplegia volume, Post-operative pneumonia and ICU stay are risk factors for PMV in adults undergoing surgical heart repair using cardiopulmonary bypass technique.