Adding a dialysis dose to continuous hemofiltration increases survival in patients with acute renal failure

Abstract

Acute renal failure (ARF) in critically ill patients is associated with high mortality. Optimal method and dose of continuous renal replacement therapy could improve survival in these patients. We studied the hypothesis that an increase in dialysis dose obtained by continuous veno-venous hemodiafiltration (CVVHDF) is associated with a better survival than continuous veno-venous hemofiltration (CVVH) among critically ill patients with ARF. In a prospective randomized trial, these two methods were compared in patients undergoing renal replacement therapy in two intensive care units (ICUs). The patients had either CVVH (1-2.5 l/h replacement fluid) or continuous CVVHDF (1-2.5 l/h replacement fluid+1-1.5 l/h dialysate) according to their body weight. 28- and 90-day mortalities, renal recovery, and duration of ICU stay were the main outcome measures. Two hundred and six patients were randomized from October 2000 to December 2003. Twenty-eight-day survivals (%) were, respectively, 39 and 59 (P=0.03) in the CVVH and CVVHDF groups. Three months survivals (%) were, respectively, 34 and 59 (P=0.0005) in the CVVH and CVVHDF groups. Apache II score, age, baseline blood urea nitrogen, and hemodiafiltration (hazard ratio 0.59, 95% confidence interval 0.40-0.87; P=0.008) were independent predictors of survival at 90 days. Renal recovery rate among survivors (71 versus 78% in the CVVH and CVVHDF groups respectively, P=0.62) was not affected by the type of renal replacement therapy. These results suggest that increasing the dialysis dose especially for low molecular weight solutes confers a better survival in severely ill patients with ARF.

Renal replacement therapy for acute renal failure: a survey of practice in adult intensive care units in the United Kingdom

“…A recent single-centre randomized controlled study found that the addition of 1-1.5 l.h )1 of dialysate flow to CVVH at 1-2.5 l.h )1 was associated with a significant increase in 28-day and 90-day survival. It was suggested that the increased removal of small molecules by haemodialysis improved control of azotaemia, and this conferred the survival advantage [18]. However, other opinion has suggested that the increased overall treatment dose provided by the addition of the dialysis element may have been responsible for the survival benefit [19].…”

Comparison of Urine Output among Patients Treated with More Intensive Versus Less Intensive RRT: Results from the Acute Renal Failure Trial Network Study

“…The use of RRT in this clinical setting is designed to optimize acid-base balance, small solute clearance, and volume control. Providing more intensive RRT (via greater solute clearance as measured by urea kinetic modeling) was, therefore, hypothesized to be beneficial (4)(5)(6). However, when tested in subsequent larger randomized, controlled trials, higher-intensity RRT in AKI has failed to improve outcomes compared with standard intensity therapy (7)(8)(9).…”

High versus standard-volume haemofiltration in hyperdynamic porcine peritonitis: effects beyond haemodynamics?

“…Haemofiltration, which is nowadays one of the most widely used hemopurification method in the ICU, failed to significantly reduce plasma cytokine concentrations and ameliorate organ dysfunction in septic patients when low ultrafiltration doses (2 l/h of plasma water exchange) were used [4]. In contrast, the importance of dialysis intensity to improve the outcome of critically ill patients with acute renal failure has been demonstrated [5][6][7]. Nonetheless, although the minimal ultrafiltration rate of 35 ml/kg per hour has been recommended [1,3], recent large multicenter trial, in which 63% of patients were septic, challenged the issue of a dosage-outcome relationship in patients with acute kidney injury [8].…”