When should Continuous Renal Replacement Therapy (CRRT) be initiated in adult patients with acute liver injury from malignant infiltration and suspected acute kidney injury (AKI) or other complications?

CRRT Initiation in Acute Liver Injury from Malignant Infiltration

In patients with acute liver injury from malignant infiltration, CRRT should only be initiated if the patient is a potential liver transplant candidate, as mortality rates exceed 89% in non-transplant candidates receiving RRT, making palliative care the more appropriate choice in this setting. 1, 2, 3

Transplant Candidacy Assessment (First Priority)

Immediately determine transplant eligibility before considering CRRT, as RRT is not recommended as stand-alone therapy for hepatorenal syndrome-AKI unless patients are transplant candidates. 1, 2

• Malignant infiltration causing acute liver failure typically precludes transplant candidacy due to active malignancy 2
• If not a transplant candidate, strongly consider palliative care rather than CRRT 2
• If potentially transplant-eligible, refer immediately for evaluation without delay 2

Absolute Indications for CRRT (If Transplant Candidate)

Initiate CRRT emergently when life-threatening complications develop: 1, 2, 4

• Severe hyperkalemia with ECG changes 4
• Refractory metabolic acidosis with impaired compensation 1, 4
• Pulmonary edema or severe volume overload causing respiratory compromise unresponsive to diuretics 1, 2, 4
• Symptomatic uremia (encephalopathy, pericarditis, bleeding) 4
• Severe refractory hyponatremia or hypernatremia 1, 2

Medical Management Before CRRT

Attempt vasoconstrictor therapy plus albumin before initiating CRRT: 1, 2

• Albumin 1 g/kg (maximum 100 g) on day 1, followed by 40-50 g/day 1, 2
• Terlipressin 0.5-2.0 mg IV every 6 hours (if available) or norepinephrine 0.5 mg/hour continuous infusion titrated to increase mean arterial pressure by ≥10 mm Hg 1, 2
• Continue for 48 hours while monitoring for response 2

Technical CRRT Implementation

Modality Selection

• Use continuous RRT (CVVHDF or CVVH) rather than intermittent hemodialysis due to hemodynamic instability in these patients 1, 2, 4
• CRRT provides superior cardiovascular stability and allows slower correction of severe hyponatremia, reducing neurological complications 2

Critical Technical Requirements

• Mandatory use of bicarbonate-buffered dialysate and replacement fluids (never lactate-buffered) 2, 4
• This is a strong recommendation (1B evidence) because patients with liver failure have impaired lactate metabolism, and lactate-buffered solutions risk worsening lactic acidosis 2, 4
• Target effluent volume of 20-25 mL/kg/hour 2, 4, 5

Anticoagulation Considerations

• Regional citrate anticoagulation can be used safely with proper monitoring, even in acute liver dysfunction 6
• Monitor total calcium/ionized calcium ratio to detect citrate accumulation 4, 6
• Keep circuit time below 50 hours to minimize complications 6

Prognostic Assessment During Treatment

Use SOFA and CLIF-SOFA scores for repeated risk stratification during CRRT to guide ongoing decision-making (AUROC 0.87 for mortality prediction). 2, 3

• SOFA and CLIF-SOFA perform significantly better than MELD or Child-Pugh scores (AUROC 0.67) for predicting mortality in this population 3
• Reassess scores at ICU admission and at CRRT initiation 3
• Hospital mortality remains 89.4% even with CRRT in acute-on-chronic liver failure with AKI 3

Critical Pitfalls to Avoid

• Do not initiate CRRT based solely on creatinine or BUN thresholds—use clinical context and absolute indications 4, 5
• Do not use lactate-buffered solutions under any circumstances in liver failure patients 2, 4
• Do not delay transplant evaluation in potential candidates who develop HRS-AKI 2
• Do not assume renal recovery based on creatinine normalization during CRRT—true recovery requires sustained RRT independence for ≥14 days 4, 5
• Monitor for volume overload carefully, as these patients have impaired sodium and water handling 2
• Avoid excessive fluid removal and hypotension to prevent re-injury to kidneys 4

Expected Outcomes

• In transplant candidates with acute liver failure and AKI, CRRT serves as a bridge to transplantation 2, 7
• Survival at 1 year post-transplant is 75.6% when CRRT is used intraoperatively and perioperatively 8
• Renal recovery occurs in 100% of transplant survivors by 1 year, though mean eGFR remains reduced at 54.7 mL/min/m² 8
• In non-transplant candidates, mortality exceeds 89% regardless of CRRT provision 3