When is Continuous Renal Replacement Therapy (CRRT) recommended in patients with severe rhabdomyolysis, particularly those with Acute Kidney Injury (AKI) or significant electrolyte imbalance?

CRRT in Rhabdomyolysis

CRRT should be initiated in rhabdomyolysis patients when life-threatening complications develop—specifically severe hyperkalemia with ECG changes, refractory metabolic acidosis, uremic complications, or fluid overload causing respiratory compromise—but not routinely based solely on elevated creatine kinase levels. 1, 2

Absolute Indications for Emergent RRT in Rhabdomyolysis

CRRT is indicated immediately when the following life-threatening conditions exist:

• Severe hyperkalemia or rapidly rising potassium with ECG changes (peaked T waves, widened QRS, loss of P waves) 1
• Severe metabolic acidosis with impaired respiratory compensation despite medical management 1
• Pulmonary edema or severe fluid overload causing respiratory compromise unresponsive to diuretics 1
• Uremic complications including encephalopathy, pericarditis, or bleeding diathesis 1
• Severe symptomatic dysnatremia resistant to conservative measures 1

Evidence Against Prophylactic CRRT

Do not initiate CRRT prophylactically in rhabdomyolysis based on creatine kinase levels alone. A 2019 Scandinavian guideline specifically recommends against routine use of renal replacement therapy as a preventive measure in rhabdomyolysis-induced AKI (weak recommendation, low quality evidence) 2. This is supported by a 2022 study demonstrating that CK levels do not predict the need for continued CRRT, and termination decisions should be based on renal function recovery rather than CK thresholds 3.

When to Choose CRRT Over Intermittent Hemodialysis

Select CRRT rather than intermittent hemodialysis when:

• Hemodynamic instability exists requiring vasopressor support (Grade 2B recommendation) 4
• Acute brain injury or increased intracranial pressure is present, as CRRT causes less cerebral edema risk (Grade 2B recommendation) 4
• Severe fluid overload cannot be adequately controlled by intermittent modalities 1, 5

For hemodynamically stable patients with severe hyperkalemia requiring rapid correction, intermittent hemodialysis may be considered as it provides faster potassium removal 1.

Technical Implementation in Rhabdomyolysis

CRRT Modality Selection

• Use CVVHDF or CVVH as the preferred modalities for hemodynamically unstable rhabdomyolysis patients 1, 6

Dosing Parameters

• Deliver effluent volume of 20-25 mL/kg/h (Grade 1A recommendation) 4, 1, 6
• This standard AKI dosing applies to rhabdomyolysis-associated AKI 4

Fluid Composition

• Use bicarbonate-based replacement fluids rather than lactate-based solutions (Grade 2C recommendation for general AKI, Grade 1B for shock) 4, 1, 6
• This is particularly important in rhabdomyolysis where metabolic acidosis and potential circulatory shock are common 1

Vascular Access

• Preferred access sites in order: right internal jugular vein, femoral vein, left internal jugular vein 5, 6
• Avoid subclavian veins due to thrombosis and stenosis risk 5, 6
• Always use ultrasound guidance for catheter insertion 5

Anticoagulation

• Regional citrate anticoagulation is preferred for patients without contraindications 5, 6
• Use heparin for intermittent hemodialysis if needed 4
• Avoid heparin products in patients with heparin-induced thrombocytopenia 4

Monitoring During CRRT

Essential monitoring parameters include:

• Electrolytes: Particularly potassium, calcium, and phosphate, as CRRT can cause hypophosphatemia and hypokalemia with prolonged treatment 7, 8, 9
• Acid-base status: Regular assessment to ensure adequate correction of metabolic acidosis 1, 8
• Fluid balance: Continuous evaluation to prevent both under- and over-resuscitation 1
• Renal function: Pre-dialysis creatinine and urine output to assess recovery 1

CRRT Termination Criteria

Consider terminating CRRT when:

• Urine output ≥1,000 mL/24 hours 3
• Serum creatinine ≤265 μmol/L (approximately 3.0 mg/dL) 3
• Hemodynamic stability achieved with vasopressor discontinuation 1, 5
• Electrolyte and acid-base disturbances controlled 1

CK levels should NOT dictate CRRT termination decisions—patients with CK >5,000 U/L at termination had similar mortality and MODS rates compared to those with CK <5,000 U/L, provided renal function had adequately recovered 3.

Critical Pitfalls to Avoid

• Do not use prophylactic CRRT based solely on elevated CK levels or as a preventive measure 2, 3
• Do not use lactate-buffered solutions in rhabdomyolysis patients who may have lactic acidosis or shock 4, 1
• Do not rely on single BUN/creatinine thresholds for initiating CRRT; consider the complete clinical picture including electrolytes, acid-base status, and volume status 5
• Avoid rapid electrolyte shifts by using appropriate CRRT dosing and monitoring 7, 8, 9
• Do not continue CRRT unnecessarily once renal function recovery criteria are met, regardless of persistent CK elevation 3

Transition to Intermittent Modalities

Transition from CRRT to intermittent hemodialysis when:

• Vasopressor support discontinued 1, 5
• Hemodynamic stability maintained 1, 5
• Fluid balance adequately controlled by intermittent sessions 1, 5
• No ongoing intracranial hypertension 1, 5