Early hemofiltration improves survival in post-cardiotomy patients with acute renal failure

Objective: The application and timing of hemofiltration (continuous veno-venous hemofiltration, CVVH) in patients with acute renal failure (ARF) post cardiac surgery has been called into question because of uncertain short-term outcome. The aim of the present study was to identify how the timing of introduction of hemofiltration affects the morbidity and mortality in patients with ARF after cardiac surgery. Methods: 1264 consecutive patients who underwent adult cardiac surgical procedures performed between January 2002 and January 2003 were audited. Out of these, case notes of 64 patients who required renal supportive intervention were reviewed. Statistical significance was accepted at a level of P≪0.05. Results: Of the 64 (5%) patients, who developed ARF and required CVVH, there were 48 males and 16 females. Mean age was 70±6.8 years. The hospital mortality was 43% (12 patients) in Group-I and 22% (8) in Group-II (P≪0.05), giving an overall 1.5% mortality associated with ARF. The mean time between the operation and the initiation of CVVH was 2.55±2.2 days in Group-I and 0.78±0.2 days in Group-II (P≪0.001). The mean duration of CVVH was 4.57±11.4 days in Group-I and 4.61±2.0 days in Group-II (P=NS). Older age (P=0.013), elevated preoperative creatinine (P=0.002), postoperative pulmonary oedema (P=0.01), sepsis (P=0.001), multiple organ failure (P=0.031), hypotension (P=0.031) and preoperative renal failure (P≪0.05) were the independent factors influencing the poor postoperative outcome and cardiac instability. Conclusion: Early and aggressive use of CVVH is associated with better than expected survival in severe ARF after cardiac operations.