From the Guidelines
To decrease the dose of continuous renal replacement therapy (CRRT), gradually reduce the effluent flow rate while monitoring the patient's clinical response, starting by decreasing the effluent rate by 5-10 mL/kg/hour from the current setting, typically reducing from 20-25 mL/kg/hour to 15-20 mL/kg/hour, as supported by the most recent evidence from 1.
Rationale for Dose Reduction
The rationale for dose reduction is to minimize complications like electrolyte disturbances and antibiotic removal while still providing adequate solute clearance. Patients with improving kidney function, decreasing metabolic demands, or resolving fluid overload are good candidates for CRRT dose reduction.
Monitoring and Adjustments
Monitor the patient's electrolytes, acid-base status, and fluid balance every 4-6 hours after making changes. Assess blood urea nitrogen (BUN) and creatinine levels at least daily to ensure adequate clearance is maintained. If the patient remains stable, further reductions can be made in 5 mL/kg/hour increments until the minimum effective dose is reached or until transitioning to intermittent hemodialysis is appropriate.
Considerations
The choice of CRRT dose should be individualized based on patient characteristics, local expertise, and nursing comfort, as noted in 1 and 1. However, the most recent and highest quality study 1 provides the basis for the recommended dose reduction strategy.
Key Points
- Gradually reduce the effluent flow rate while monitoring the patient's clinical response
- Start by decreasing the effluent rate by 5-10 mL/kg/hour from the current setting
- Monitor electrolytes, acid-base status, and fluid balance every 4-6 hours
- Assess BUN and creatinine levels at least daily
- Consider transitioning to intermittent hemodialysis when appropriate
- Always consult with nephrology before making significant changes to CRRT prescriptions, as emphasized in the example answer guided by 1, 1, and 1.
From the Research
Decreasing the Dose of Continuous Renal Replacement Therapy (CRRT)
To decrease the dose of CRRT, several factors should be considered:
- The delivered CRRT effluent dose for critically ill patients with AKI should be 20-25 ml/kg/h on average, as supported by solid evidence 2
- Prescribing 25-30 ml/kg/h of effluent dose can account for treatment interruptions and the natural decline in filter efficiency over time 2
- Transient higher doses of CRRT may be needed in specific clinical scenarios to accommodate specific solute control needs of a particular patient at a given time 2
- Consideration of the potential adverse consequences of non-selective clearance, such as undesired antimicrobials and nutrients removal, is necessary 2
Monitoring and Adjusting CRRT Dose
- The dose of CRRT should be systematically monitored (prescribed vs. delivered) and iteratively adjusted in a sustainable mode 3
- A framework for monitoring and implementation of CRRT dose as a quality indicator of CRRT delivery should be established 2
- Hourly fluid balance in patients receiving CRRT should be closely monitored, as an early negative fluid balance is associated with decreased ICU mortality 4
Practical Considerations
- Errors in fluid prescription, compounding, or delivery can be rapidly fatal, and therefore, a tailored approach to adjusting fluid composition and regulating CRRT dose may be necessary 5
- Methods and procedures to extend CRRT system life may improve the dose delivery, as many patients are prescribed low doses of CRRT and the dose delivered is considerably lower than that prescribed 6