How do we approach renal replacement therapy (RRT) in a patient with cirrhosis and acute kidney injury (AKI)?

Approach to Renal Replacement Therapy in Cirrhotic Patients with AKI

In cirrhotic patients with AKI, RRT should be initiated primarily for transplant candidates who fail vasoconstrictor therapy, or for any patient with life-threatening metabolic derangements, using continuous RRT (CRRT) with bicarbonate-buffered solutions and regional citrate anticoagulation when possible. 1

Initial Management Before Considering RRT

Before initiating RRT, optimize medical management systematically:

• Withdraw all diuretics, nephrotoxic drugs (NSAIDs, ACE inhibitors, aminoglycosides), and vasodilators immediately 1
• Administer albumin 1 g/kg body weight (maximum 100 g/day) for 2 consecutive days to treat prerenal AKI and establish HRS-AKI diagnosis 1
• Aggressively identify and treat infections (spontaneous bacterial peritonitis, pneumonia, urinary tract infections), as infection is the most common precipitant of AKI in cirrhosis 1

For Stage 2 or greater HRS-AKI after volume expansion:

• Initiate vasoconstrictors plus albumin 20-40 g/day: terlipressin 0.5-2.0 mg IV q6h (or continuous infusion 2 mg/24h titrated to maximum 12 mg/day) or norepinephrine 0.5 mg/h titrated to maximum 3 mg/h 1
• Monitor for response over 3-7 days before declaring treatment failure 1

Indications for RRT Initiation

Absolute Indications (Apply to All Cirrhotic Patients)

Initiate RRT emergently for life-threatening conditions regardless of transplant candidacy: 1

• Severe hyperkalemia with ECG changes
• Severe metabolic acidosis with impaired compensation
• Pulmonary edema or severe volume overload causing respiratory compromise
• Symptomatic uremia (encephalopathy, pericarditis, bleeding)
• Severe refractory hyponatremia

Relative Indications (Transplant Status-Dependent)

The decision to initiate RRT for HRS-AKI specifically depends critically on liver transplant candidacy: 1

• For transplant candidates: Initiate RRT after failure of vasoconstrictor therapy (non-response after 3-7 days) to serve as bridge to transplantation 1
• For non-transplant candidates: RRT should be individualized based on severity of illness, prognosis, and goals of care, as mortality exceeds 85% at 6 months in this population 1, 2

Critical caveat: Recent evidence demonstrates that critically ill cirrhotic patients requiring RRT have very high mortality independent of transplant options, so decisions should be based on individual severity of illness using repeated risk stratification with SOFA/CLIF-SOFA scores, not solely on transplant candidacy 1

RRT Modality Selection

Use CRRT rather than intermittent hemodialysis in cirrhotic patients with AKI for the following reasons: 1

• Hemodynamic instability is nearly universal in decompensated cirrhosis with AKI requiring RRT 1
• CRRT provides superior cardiovascular stability and allows slower correction of severe hyponatremia (common in cirrhosis), reducing neurological complications 1
• Target effluent volume of 20-25 mL/kg/hour 1

Critical Technical Specifications for Cirrhotic Patients

Buffer Selection (Strong Recommendation)

Use bicarbonate-buffered (NOT lactate-buffered) dialysate and replacement fluids in all cirrhotic patients 1, 3

• This is a 1B recommendation (strong evidence) because cirrhotic patients have impaired lactate metabolism 1
• Lactate-buffered solutions risk worsening lactic acidemia and metabolic acidosis 1
• This applies to patients with circulatory shock AND liver failure 1

Anticoagulation Strategy

Cirrhotic patients present a unique anticoagulation challenge despite abnormal coagulation tests:

• First choice: Regional citrate anticoagulation for CRRT in patients without contraindications (preferred over heparin even in patients with "increased bleeding risk" based on traditional coagulation tests) 1
• Monitor for citrate accumulation in severe liver failure: check ionized calcium and total calcium/ionized calcium ratio 4
• Avoid heparin in patients with increased bleeding risk 1
• If citrate contraindicated: Use unfractionated or low-molecular-weight heparin 1

Important note: Argatroban should NOT be used in severe liver failure if HIT develops; consider Factor Xa inhibitors instead 1

Vascular Access

Use uncuffed non-tunneled dialysis catheter for acute RRT initiation 1

Preferred insertion sites in order:

1. Right internal jugular vein (first choice)
2. Femoral vein (second choice)
3. Left internal jugular vein (third choice)
4. Subclavian vein (last choice - avoid due to stenosis risk) 1

Use ultrasound guidance for insertion (1A recommendation) and obtain chest radiograph before first use for internal jugular or subclavian placement 1

Monitoring and Fluid Management

Volume management is particularly complex in cirrhotic patients:

• Monitor closely for pulmonary edema during albumin administration, as cirrhotic cardiomyopathy and diastolic dysfunction are common 1
• Assess fluid status frequently as these patients have impaired sodium and water handling 3
• Avoid excessive ultrafiltration which can worsen effective arterial underfilling and precipitate further hemodynamic compromise 1

Timing of RRT Discontinuation

Discontinue RRT when:

• Kidney function has recovered (defined as sustained independence from RRT for ≥14 days) 1, 4
• Patient undergoes liver transplantation and renal function improves
• RRT becomes inconsistent with goals of care 1

Do not rely on serum creatinine alone to assess renal recovery during RRT, as it is artificially reduced by dialysis 4

Transplant Considerations

Liver transplantation is the definitive treatment for HRS-AKI 1

Simultaneous liver-kidney transplant (SLK) criteria: 1

• AKI on RRT for ≥4 weeks, OR
• Estimated GFR ≤35 mL/min or measured GFR ≤25 mL/min for ≥4 weeks

Critical point: Pretransplant treatment with terlipressin significantly decreases the need for post-transplant RRT and improves outcomes 5

Prognostic Considerations and Goals of Care

Mortality data to inform decision-making:

• Transplant-ineligible patients initiated on RRT have median survival of 12.5 days, with only 15% alive at 6 months 2
• 88% of RRT patients die in the ICU setting 2
• HRS-AKI patients are more likely to remain RRT-dependent (86%) compared to ATN patients (27%) at 6 months 2

For non-transplant candidates who fail vasoconstrictor therapy, strongly consider palliative care consultation rather than RRT initiation 1

Common Pitfalls to Avoid

• Do not delay transplant evaluation in patients with HRS-AKI who are potential candidates; refer immediately 1
• Never use lactate-buffered solutions in cirrhotic patients under any circumstances 1, 3
• Do not assume renal recovery based on creatinine values during RRT; true recovery requires sustained independence from RRT for ≥14 days 4
• Do not initiate RRT in non-transplant candidates with HRS-AKI without thorough goals-of-care discussions, given the extremely poor prognosis 1, 2