Acute renal failure following cardiopulmonary bypass: a changing picture

Objective:To assess the incidence of acute renal failure (ARF) developing p erioperatively in adult patients requiring cardiopulmonary bypass surgery ( CPB) and to make comparisons with data from the same institution published earlier. Design: Prospective, observational. Setting: Tertiary referral centre for cardiopulmonary medicine. Patients an d participants: All patients admitted to the intensive care unit (ICU) who developed ARF perioperatively necessitating continuous veno-venous haemofil tration (CVVH) during the 24 months January 1997-December 1998. Interventions: None. Measurements and results: Of 2337 adult patients undergoing cardiac surgery , 47 (2.0%)needed CVVH. Patients were excluded from analysis who underwent cardiac transplantation (n = 4), pericardial surgery (n = 3) or insertion o f a left ventricular assist device (n = 1). Of the remaining 39, 21 patient s died in ICU (53.8% mortality). Relatively more non-survivors suffered fro m diabetes, hypertension and preoperative renal dysfunction. A previous rep ort from our Unit revealed that, in 1989-90, 2.7% of all patients undergoin g CPB required CVVH with an in-hospital mortality of 83%. The current study population were older (65.3 vs 56.0 years in 1990), and more severely ill as evidenced by a higher percentage of patients requiring redo (30% vs 8.6% in 1990) and emergency (50% vs 25.7% in 1990) surgery. Conclusions: The need for CVVH following CPB may be diminishing despite inc reased risk factors. ARF-associated mortality in these circumstances is fal ling.