What is the recommended treatment for non-traumatic rhabdomyolysis using Lactated Ringer's (LR) solution?

Treatment of Non-Traumatic Rhabdomyolysis with Lactated Ringer's Solution

For non-traumatic rhabdomyolysis, early aggressive fluid resuscitation with Lactated Ringer's solution is recommended as it requires less volume than normal saline and results in less hyperchloremic acidosis while effectively treating the condition.

Pathophysiology and Importance of Early Treatment

Rhabdomyolysis is characterized by the breakdown of skeletal muscle with release of myoglobin into circulation, which can lead to:

• Acute kidney injury
• Electrolyte imbalances (particularly hyperkalemia)
• Metabolic acidosis
• Compartment syndrome in severe cases

Early aggressive fluid resuscitation is critical to prevent these complications, particularly myoglobinuric acute kidney injury 1.

Fluid Choice for Rhabdomyolysis

Lactated Ringer's vs. Normal Saline

Lactated Ringer's solution offers several advantages over normal saline in non-traumatic rhabdomyolysis:

1. Reduced risk of hyperchloremic acidosis

   • LR causes less hyperchloremic acidosis compared to normal saline 2
   • Normal saline administration results in significant hyperchloremia (119 ± 1.9 mEq/L vs. 105 ± 2.9 mEq/L) and acidosis (pH 7.28 ± 0.12 vs. 7.45 ± 0.06) compared to LR 3

2. Lower volume requirements

   • LR requires significantly less volume than normal saline for resuscitation 3
   • Lower volume requirements may reduce the risk of fluid overload

3. Better preservation of coagulation factors

   • Normal saline results in lower fibrinogen levels compared to LR 3

4. Reduced mortality and AKI risk

   • Higher percentage of LR in fluid resuscitation is associated with lower mortality and less acute kidney injury in critically ill patients 4

Important Exceptions

While LR is generally preferred, there are specific situations where normal saline should be used instead:

1. Traumatic brain injury

   • Avoid LR in patients with traumatic brain injury due to its relative hypotonicity 5, 6
   • Normal saline is preferred in TBI patients due to higher sodium content and osmolality 6

2. Severe hyperkalemia

   • Consider normal saline if patient has severe hyperkalemia, as LR contains potassium (4 mEq/L) 6

3. When administering blood products

   • Use normal saline when administering blood products to avoid calcium-citrate interaction 6

Fluid Resuscitation Protocol for Non-Traumatic Rhabdomyolysis

1. Initial resuscitation:

   • Begin with aggressive fluid resuscitation using Lactated Ringer's solution
   • Target rate: ≥12 L daily (approximately 400 ml/hour) 1, 2
   • Continue for at least the first 12 hours 2

2. Monitoring parameters:

   • Urine output: Target 1-2 mL/kg/hour for patients with myoglobinuria 6
   • Serum creatine kinase levels: Monitor until normalization
   • Electrolytes: Particularly potassium, calcium, phosphate
   • Acid-base status: Monitor pH and bicarbonate
   • Renal function: BUN, creatinine

3. Adjunctive measures:

   • Consider sodium bicarbonate supplementation if acidosis persists (though less likely needed with LR than with normal saline) 2
   • Consider mannitol or loop diuretics if adequate urine output is not achieved despite fluid resuscitation

Practical Considerations

• LR may cause a transient increase in serum lactate levels, which should not be interpreted as worsening tissue perfusion 7
• Patients with chronic liver disease may have impaired lactate metabolism, requiring closer monitoring 6
• Adjust fluid rates based on clinical response rather than rigid formula calculations 6
• Continue fluid therapy until CK levels decrease substantially (typically <5,000 U/L) and renal function stabilizes

Common Pitfalls to Avoid

1. Inadequate fluid resuscitation: Insufficient volume can lead to persistent myoglobinuric kidney injury
2. Delayed initiation: Early intervention is critical for preventing complications
3. Overreliance on urine alkalinization: While previously emphasized, the primary benefit comes from volume expansion rather than urinary pH manipulation
4. Failure to monitor for compartment syndrome: Especially in cases with severe muscle damage
5. Ignoring comorbidities: Adjust fluid strategy for patients with heart failure, kidney disease, or liver disease

By following these guidelines, early aggressive fluid resuscitation with Lactated Ringer's solution can significantly reduce mortality and complications in patients with non-traumatic rhabdomyolysis.