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Optimal Mode of clearance in critically ill patients with Acute Kidney Injury (OMAKI) - a pilot randomized controlled trial of hemofiltration versus hemodialysis: a Canadian Critical Care Trials Group project

Ron Wald12*, Jan O Friedrich234, Sean M Bagshaw5, Karen EA Burns234, Amit X Garg6, Michelle A Hladunewich78, Andrew A House6, Stephen Lapinsky49, David Klein10234, Neesh I Pannu11, Karen Pope10, Robert M Richardson12, Kevin Thorpe10 and Neill KJ Adhikari47

  • * Corresponding author: Ron Wald waldr@smh.ca

  • † Equal contributors

Author Affiliations

1 Division of Nephrology, St. Michael's Hospital, 30 Bond Street, Toronto, ON, M5B 1W8, Canada

2 Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael's Hospital, 30 Bond Street, Toronto, ON, M5B 1W8, Canada

3 Critical Care and Medicine Departments, St. Michael's Hospital, 30 Bond Street, Toronto, ON, M5B 1W8, Canada

4 Interdepartmental Division of Critical Care, University of Toronto, 30 Bond Street, Toronto, ON, M5B 1W8, Canada

5 Division of Critical Care Medicine, University of Alberta, 8440 112 Street NW. Edmonton, AB, T6G 2B7, Canada

6 Division of Nephrology, London Health Sciences Centre, 800 Commissioners Road East, London, ON, N6A 5W9, Canada

7 Division of Nephrology, Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Toronto, ON, M4N 3M5, Canada

8 Department of Critical Care Medicine and Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Toronto, ON, M4N 3M5, Canada

9 Division of Critical Care, Mt. Sinai Hospital, 600 University Avenue, Toronto, ON, M5G 1X5, Canada

10 Applied Health Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, 30 Bond Street, Toronto, ON, M5B 1W8, Canada

11 Division of Nephrology, University of Alberta Hospital, 8440 112 Street NW, Edmonton, Alberta, T6G 2B7, Canada

12 Division of Nephrology, University Health Network, 200 Elizabeth Street, Toronto, ON, M5G 2C4, Canada

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Critical Care 2012, 16:R205  doi:10.1186/cc11835

Published: 24 October 2012

Abstract

Introduction

Among critically ill patients with acute kidney injury (AKI) needing continuous renal replacement therapy (CRRT), the effect of convective (via continuous venovenous hemofiltration [CVVH]) versus diffusive (via continuous venovenous hemodialysis [CVVHD]) solute clearance on clinical outcomes is unclear. Our objective was to evaluate the feasibility of comparing these two modes in a randomized trial.

Methods

This was a multicenter open-label parallel-group pilot randomized trial of CVVH versus CVVHD. Using concealed allocation, we randomized critically ill adults with AKI and hemodynamic instability to CVVH or CVVHD, with a prescribed small solute clearance of 35 mL/kg/hour in both arms. The primary outcome was trial feasibility, defined by randomization of >25% of eligible patients, delivery of >75% of the prescribed CRRT dose, and follow-up of >95% of patients to 60 days. A secondary analysis using a mixed-effects model examined the impact of therapy on illness severity, defined by sequential organ failure assessment (SOFA) score, over the first week.

Results

We randomized 78 patients (mean age 61.5 years; 39% women; 23% with chronic kidney disease; 82% with sepsis). Baseline SOFA scores (mean 15.9, SD 3.2) were similar between groups. We recruited 55% of eligible patients, delivered >80% of the prescribed dose in each arm, and achieved 100% follow-up. SOFA tended to decline more over the first week in CVVH recipients (-0.8, 95% CI -2.1, +0.5) driven by a reduction in vasopressor requirements. Mortality (54% CVVH; 55% CVVHD) and dialysis dependence in survivors (24% CVVH; 19% CVVHD) at 60 days were similar.

Conclusions

Our results suggest that a large trial comparing CVVH to CVVHD would be feasible. There is a trend toward improved vasopressor requirements among CVVH-treated patients over the first week of treatment.

Trial Registration

ClinicalTrials.gov: NCT00675818