Prognosis of critically-ill patients with acute renal failure: APACHE II score and other predictive factors.

The survival from acute renal failure requiring renal replacement therapy was studied in 90 critically-ill patients admitted to an intensive care unit. Mean age (+/- SD) was 51 +/- 14.6 (range 17 to 81) years. Mechanical ventilation was required in 88 patients and 71 patients received total parenteral nutrition. Thirty-three per cent of patients left the intensive care unit alive and 24 per cent survived to leave hospital. Final survival was 20 per cent in medical patients (n = 49), 29 per cent in surgical patients (n = 38) and 100 per cent in obstetric patients (n = 3). Hypotension, requirement for inotropic support, oliguria and sepsis were all associated with a poorer prognosis. The mode of renal replacement therapy did not affect survival, but additional haemodialysis was required in 33 of 65 patients treated by continuous arteriovenous haemofiltration but none of 22 treated with continuous arteriovenous haemodialysis (p less than 0.001). APACHE II score was calculated for 87 patients. Mean APACHE II score was 26.1 +/- 6.9 (range 14 to 44). APACHE II score on admission predicted the likelihood of survival well. No patients with a score of more than 40 survived, compared to 40 per cent of those with scores of 10 to 19. Pre-existing organ insufficiency or immunosuppression meriting a CHE score of 5 was associated with a very poor survival (1 of 30 patients). APACHE II score is a reliable indicator of severity of illness and likelihood of survival in critically-ill patients with acute renal failure. The widespread adoption of APACHE II scoring for patients with acute renal failure requiring intensive care would facilitate medical audit and comparison of studies from various centres.