Impact of oxygen delivery on the development of acute kidney injury in patients undergoing valve heart surgery

Abstract

One of the strongest risk factors for death in individuals undergoing cardiac surgery is Cardiac Surgery Associated-Acute Kidney Injury (CSA-AKI). Although the minimum kidney oxygen delivery index (DO2i) during cardiopulmonary bypass (CPB) has been reported, the optimal threshold value has not yet been established. A prospective study was conducted from June 2012 to January 2016 to asses how DO2i influences the pathogenesis of CSA-AKI, as well as its most favorable cut-off value. DO2 levels were recorded at the beginning, middle, and end of the CPB. The association between DO2i and CSA-AKI was investigated using multivariable logistic regression analysis. The optimal cut-off of DO2i as a predictor of CSA-AKI was determined using Classification and Regression Tree (CART) analysis. A total of 782 consecutive patients were enrolled. Of these, 231 (29.5%) patients developed AKI. Optimal DO2i thresholds of 303 mL/min/m2 during the CPB and 295 mL/min/m2 at the end of the intervention were identified, which increased the odds of CSA-AKI almost two-fold (Odds Ratio (OR), 1.90; 95% CI, 1.12-3.24) during the surgery and maintained that risk (OR 1.94; 95% CI, 1.15-3.29) until the end. Low DO2i during cardiopulmonary bypass is a risk factor for CSA-AKI that cannot be ruled out. Continuous renal oxygen supply monitoring for adult patients could be a promising method for predicting AKI during CPB.