Acute renal failure in cardiothoracic surgery patients: what is the best definition of this common and potent predictor of increased morbidity and mortality

Background Universal agreement on criteria for acute renal failure (ARF) is lacking. The purpose of the current study was to determine which of 6 definitions for ARF best predicted clinical outcomes in postoperative cardiothoracic surgery (CTS) patients. Methods Criteria for ARF were retrospectively applied to 1,085 CTS patients. General linear models analyzed length of stay (LOS) and ventilator days with logistic regression for mortality. Results Thirty-seven percent of patients met at least 1 of 6 definitions of ARF. For each 1-mg/dL increase from the initial creatinine, LOS increased by 6.96 days, ventilator days increased by 3.58 days, and mortality increased by 2.23 times (P < .0001). Conclusions One definition that best predicted ARF was not found. ARF was a significant independent predictor of increased mortality, LOS, and ventilator days. Even small increases in creatinine correlate with clinically significant worsening of expected outcomes.