Postoperative acute kidney injury in high-risk patients undergoing major abdominal surgery

PurposeAcute kidney injury (AKI) is a frequent complication in high-risk patients undergoing major surgery and is associated with longer hospital stay, increased risk for nosocomial infection and significantly higher costs.Materials and methodsA prospective observational study exploring the incidence of AKI (AKIN classification at any stage) in high-risk patients within 48 hours after major abdominal surgery was conducted. Patients' preoperative characteristics, intraoperative management, and outcome were evaluated for associations with AKI using a logistic regression model.ResultsData from 258 patients were analyzed. Thirty-one patients (12%) developed AKI, reaching the AKIN stage 1. No patient reached an AKIN stage higher than 1. AKI patients were older (75.2 vs 70.2 years; P = 0.0113) and had a higher body mass index (26.5 vs 25.1 kg/m2). In addition, AKI patients had a significantly longer ICU length of stay (3.4 vs 2.4 days; P= .0017). Creatinine levels of AKI patients increased significantly compared to the preoperative levels at 24 (P= .0486), 48 (P= .0011) and 72 hours (P= .0055), while after 72 hours it showed a downwards trend. At ICU discharge, 28 out of 31 patients (90.3%) recovered preoperative levels.Multivariate analysis identified age (OR 1.088; P= .002) and BMI (OR 1.124; P= .022) as risk factors for AKI development. Moreover, AKI development was an independent risk factor for ICU stays longer than 48 hours (OR 2.561; P= .019).ConclusionsMild AKI is a not rare complication in high-risk patients undergoing major abdominal surgery. Although in almost the totality of cases, the indicators of renal function recovered to preoperative levels, post-operative AKI represents a primary risk factor for a prolonged ICU stay.