Predictors of acute renal failure requiring renal replacement therapy post cardiac surgery in patients with preoperatively normal renal function

Acute renal failure requiring continuous renal replacement therapy post cardiac surgery carries a high mortality. Most studies have focused on patients with impaired renal function preoperatively but little is known about predictors of such a complication in patients with preoperatively normal renal function. This is a retrospective review of a prospective collected database. A total of 1609 patients underwent cardiac surgery over a 4-year period. Dialysis was required in 47 patients (2.9%). Univariate analysis identified the following as significant risk factors: age, female gender, chronic obstructive pulmonary disease, congestive cardiac failure, creatinine clearance, Euro, Parsonnet and Cleveland clinic scores, body mass index, non-isolated CABG, cardiopulmonary bypass time, extubation time and pulmonary complications (P<0.05). Multivariate analysis identified EuroSCORE, congestive cardiac failure, insulin-dependent diabetes, emergency surgery, postoperative extubation time and pulmonary complications as independent risk factors (P<0.05). In-hospital mortality and length of stay (P<0.0001) were higher in dialysis group. Acute renal failure requiring dialysis post cardiac surgery is associated with a higher mortality and prolonged hospital stay. By identifying higher risk patients, early planned preventative measures should be readily available to both reduce the incidence of such a complication and improve utilisation of hospital resources.