Acute Kidney Injury after adult Cardiac Surgery with Cardiopulmonary Bypass: Incidence and Predictors

Aim: To study the incidence and predictorsfor postoperative acute kidney injury in adults undergoing cardiac surgery using cardiopulmonary bypass in Pakistani population Methods: This prospective observational study was performed at the Department of Cardiac Surgery, Punjab Institute of Cardiology, Lahore, Pakistan over a period of 6 months from 1st March 2013 to 1st September 2013. All those adult patients undergoing cardiac surgery with a cardiopulmonary bypass were included in the study. Preoperative, per operative and cardiopulmonary bypass related variables were studied prospectively. Acute kidney injury was diagnosed as postoperative creatinine > 1.6 mg/ dl, in the postoperative period in ICU within the first 24 hours after surgery. The Data was analyzed using SPSS version 16.0. P-value <= 0.05 were considered significant. Results: Out of 250 patients, (39.13%) patients were females and (60.87%) patients were male. Acute kidney injury was observed in 16 (6.5%) patients. Predictors of postoperative kidney injury identified by Logistic Regression were Diabetes Mellitus (OR: 1.50, CI 95%: 0.47-4.83; P value = 0.004), Hypertension (OR: 3.819, CI: 95%, 0.79-18.35), Pre-op urea (OR: 1.88, CI: 95%, 0.43-1.78, P= 0.001), Pre-op creatinine (OR: 1.93, CI: 95%, 0.74-1.84, P= 0.001), CPB time (OR: 1.01, CI: 95%, 0.98-1.039, P= 0.001), Cross clamp time (OR: 1.01, CI 95%: 0.93-0.99; P value = 0.001) and Lowest hematocrit on pump (OR: 1.89, CI: 95%, 0.90-3.98, P= 0.001). Conclusion: Acute kidney injury (AKI) is a significant complication after cardiac surgery. Predictors of acute kidney injury are Diabetes Mellitus, Hypertension, Pre-op urea, pre-op creatinine, cardiopulmonary bypass time, cross clamp time, lowest hematocrit on pump.