Acute renal failure following cardiopulmonary bypass: a changing picture

Objective:To assess the incidence of acute renal failure (ARF) developing perioperatively 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 and participants: All patients admitted to the intensive care unit (ICU) who developed ARF perioperatively necessitating continuous veno-venous haemofiltration (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 of a left ventricular assist device (n = 1). Of the remaining 39, 21 patients died in ICU (53.8% mortality). Relatively more non-survivors suffered from diabetes, hypertension and preoperative renal dysfunction. A previous report from our Unit revealed that, in 1989-90, 2.7% of all patients undergoing 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 increased risk factors. ARF-associated mortality in these circumstances is falling.