Indications for Terminating CRRT
CRRT should be discontinued when intrinsic kidney function has recovered sufficiently to maintain metabolic homeostasis without extracorporeal support, or when continued therapy is no longer consistent with the patient's goals of care. 1
Primary Criteria for CRRT Discontinuation
Renal Recovery Indicators
Urine output is the most robust and commonly used predictor of successful CRRT discontinuation, with a sensitivity of 66.2% and specificity of 73.6% for predicting successful liberation from RRT. 1 While specific thresholds vary across studies, adequate urine production prior to stopping CRRT is the single most reliable clinical marker. 1
Creatinine clearance and creatinine ratio are the strongest biochemical predictors of successful discontinuation:
- A creatinine clearance ≥11 mL/min (measured over 6 hours on day 2 after stopping CRRT) predicts successful discontinuation with an area under the curve of 0.791. 2
- A creatinine ratio (day 2/day 0) ≤1.41 is the optimal cut-off for predicting successful discontinuation, with even stronger discriminative ability (AUC 0.819). 2
- Lower creatinine ratios indicate improving renal function, while ratios >1.41 suggest ongoing kidney injury. 2
Clinical Status Assessment
Non-renal organ function must be considered, as patients with lower non-renal SOFA scores have significantly higher rates of successful CRRT discontinuation. 2 Specifically:
- Absence of vasopressor requirement is associated with successful discontinuation. 2
- Lower cumulative fluid balance (from day 0-2 after stopping) predicts success. 2
- Shorter duration of CRRT correlates with successful discontinuation. 2
Absolute Indications for Continuing CRRT
Do not discontinue CRRT if any of the following persist:
- Oliguria/anuria (<400 mL/24h) unresponsive to conservative management 3
- Life-threatening hyperkalemia (K+ >6.5 mEq/L or ECG changes) refractory to medical therapy 3
- Pulmonary edema unresponsive to diuretics 3
- Severe metabolic acidosis (pH <7.1) not correctable with bicarbonate 3
- Uremic complications (pericarditis, encephalopathy, bleeding) 3
Practical Algorithm for CRRT Discontinuation
Step 1: Assess Readiness for Trial Off CRRT
Before attempting discontinuation, verify:
- Patient is producing urine (specific volume thresholds vary, but any meaningful output is favorable) 1
- No absolute indications for RRT persist 3
- Hemodynamic stability without escalating vasopressor support 2
- Improving or stable non-renal organ function 2
Step 2: Measure Baseline Parameters
On the day of potential discontinuation (Day 0), document:
- Serum creatinine
- Urine output over preceding 24 hours
- Fluid balance
- SOFA score (particularly non-renal components) 2
Step 3: Trial Period Off CRRT
Stop CRRT and monitor for 48 hours (Day 2 assessment):
- Measure 6-hour creatinine clearance on Day 2 2
- Calculate creatinine ratio (Day 2 creatinine / Day 0 creatinine) 2
- Monitor urine output continuously 2
- Track cumulative fluid balance 2
Step 4: Decision Point at 48 Hours
Successful discontinuation is predicted by:
- Creatinine clearance ≥11 mL/min 2
- Creatinine ratio ≤1.41 2
- Sustained urine output 2
- No vasopressor escalation 2
- Stable or improving non-renal SOFA score 2
If these criteria are met, continue monitoring without restarting CRRT. If criteria are not met or clinical deterioration occurs, reinitiate CRRT. 2
Goals of Care Considerations
CRRT should be discontinued when it is no longer consistent with the patient's goals of care, regardless of renal function status. 1 This represents a separate and equally valid indication for termination, particularly in patients with poor prognosis or those transitioning to comfort-focused care. 1
Common Pitfalls to Avoid
Do not rely solely on absolute BUN or creatinine values to determine discontinuation timing, as these are less predictive than dynamic measures like creatinine clearance and creatinine ratio. 3, 2
Do not wait for "normal" kidney function before attempting discontinuation—the goal is adequate function to maintain homeostasis, not complete normalization. 1
Do not ignore non-renal organ dysfunction, as multiorgan failure significantly reduces the likelihood of successful CRRT discontinuation even with improving kidney function. 2
Avoid premature discontinuation in patients still requiring vasopressors or with worsening fluid balance, as these predict failure to remain off RRT. 2
Monitor for nutrient losses (10-15g amino acids/day) and electrolyte depletion during CRRT, as severe deficiencies may complicate the discontinuation process. 4