Dosing patterns for continuous renal replacement therapy in the United States

Introduction

There is evidence that increasing the dose of continuous renal replacement therapy (CRRT) is associated with improved survival in critically ill patients with acute renal failure (ARF) [1]. In the US, CRRT is usually provided with an ultrafiltrate (UF) and/or dialysis flow rate of 2 l/h irrespective of the patient's weight. Patients undergoing CRRT frequently have their therapy interrupted and hence receive a much lower dose than prescribed. Hence we retrospectively reviewed the records of all patients with ARF, who received CRRT in our hospital in the past year, to determine dosing patterns.

Methods

Computerized records of all patients (n = 115) who received CRRT for ARF in our institution from September 1999 to August 2000 were reviewed. Patients were included in analysis if they received CRRT for at least 2 days and their hospital discharge outcome was known. All but four patients met these inclusion criteria. The patient's CRRT dose for each day was inferred from the hourly UF/dialysis flow rate and the duration (in hours) of CRRT for that day. A mean UF/dialysis flow rate (in l/h) for each patient was then calculated. Other patient demographic characteristics including age, weight and duration of therapy were obtained from the patient's records.

Results

The average number of hours/day on CRRT was 16.1, with a mean flow rate of 1.36 l/h. The mean CRRT dose for these patients was only 16.50 ml/kg/h, much lower than the lowest dose (20 ml/kg/h) used by Ronco et al [1].

Conclusion

In the US, many patients are prescribed a lower dose of CRRT than supported by current evidence. Moreover, the actual dose delivered is much lower than that prescribed. Immediate changes in dosing practices are necessary to achieve the doses recently shown to be beneficial in patients with ARF [1]. A weight-based dosing regime may enable physicians to achieve increased dosing of CRRT in such patients.

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