Usefulness of prolonged renal replacement therapy in patients with acute kidney injury requiring dialysis

Acute kidney injury (AKI) requiring dialysis is becoming more common. Several types of renal replacement therapies have been used, including continuous, intermittent, and prolonged intermittent renal replacement therapy (PIRRT). There is no clear difference between those therapies in terms of patient survival. The aim of this study was to describe a form of PIRRT (shift continuous veno-venous hemodialysis [CVVHD]) and the results of this technique in a population of patients with AKI requiring dialysis in a tertiary care center. We studied 302 patients with AKI requiring dialysis over a 3-year period. All patients were treated in the intensive care unit. There were 1709 treatments in the study. Shift CVVHD was done for 8 h daily using NxStage machines, with a bicarbonate base dialysate at a rate of 5 L/h. Demographics and laboratory data were obtained from the electronic medical record. Dialysis data were obtained from the dialysis run sheets. Patient mortality was 51.3%.The dialysis time was close to 8 h and the blood flow was 310 (± 43) mL/min. The mean arterial pressure was stable before and after the dialysis. The total ultrafiltration averaged 2934 mL per treatment; the ultrafiltration rate was 4.1 (± 3.1) mL/kg/h, and the ultrafiltration per hour was 359 (± 257.8) mL/h. The average dialysate potassium used was 2.9 mEq/L. The dose of dialysis was 57 (± 19) mL/kg/h. The urea reduction ratio was 48% (± 15%), the standardized KT/V (a measure of dialysis dose obtained by urea kinetic modeling) was 3.5 (± 0.9), and the equivalent renal urea clearance (EKR) was 9.8 (± 4.1) mL/min. The method produced a consistent reduction in the levels of blood urea nitrogen, creatinine, potassium, and phosphorous. The delivered dose of dialysis was stable during the observation period. In conclusion, shift CVVHD is effective in treating patients with AKI requiring dialysis and has a survival similar to that of continuous therapies with less intensive use of resources.