Late initiation of continuous veno-venous hemofiltration therapy is associated with a lower survival rate in surgical critically ill patients with postoperative acute kidney injury

There is controversy about the appropriate timing for renal replacement therapy in patients with acute kidney injury (AKI). We are interested in the appropriate timing for initiation of continuous renal replacement therapy in critically ill surgical patients with postoperative acute kidney injury. Seventy-three critically ill surgical patients with postoperative AKI who received continuous renal replacement therapy (CRRT) were enrolled. Indications for CRRT were: 1) AKI with hyperkalemia, 2) metabolic acidosis, 3) pulmonary edema refractory to diuretics, and 4) oliguria with progressive azotemia, especially in unstable hemodynamics. Using RIFLE (Risk, Injury, Failure, Loss, End stage) classification, patients who received CRRT in the "Risk" stage were defined as early group, whereas those in the "Injury/ Failure" stage were labeled as late group. We used continuous veno-venous hemofiltration as CRRT in this series. There were 20 patients in the early group and 53 patients in the late group. The mean ages were 61.5 ± 21.8 years versus 60.8 ± 17.5 years. The mortality rate was 50 per cent versus 84.9 per cent. There were no significant differences in demographic characteristics or type of surgery or physiological scores. Our data show that late initiation of CRRT is associated with a lower survival rate in critically ill surgical patients with postoperative AKI; however, further studies are required.