What is the appropriate IV fluid to administer in rhabdomyolysis?

Appropriate IV Fluid Management in Rhabdomyolysis

Normal saline (0.9% NaCl) is the recommended first-line IV fluid for rhabdomyolysis to prevent acute kidney injury and reduce the need for dialysis. 1, 2

Rationale for Normal Saline Selection

• Normal saline is preferred over lactated Ringer's or other potassium-containing balanced crystalloids in rhabdomyolysis due to the risk of hyperkalemia from muscle breakdown 3
• The absence of potassium in normal saline makes it safer in the initial management phase when patients may already have elevated potassium levels from muscle damage
• Aggressive IV fluid resuscitation with normal saline has been shown to decrease the incidence of acute renal failure and need for dialysis in patients with rhabdomyolysis 2

Fluid Administration Protocol

Initial Resuscitation

• Begin with normal saline at 1 L/hour during extrication (if applicable) 1
• After extrication or upon diagnosis, continue aggressive fluid resuscitation with normal saline at rates sufficient to maintain urine output of at least 300 mL/hour 4
• Target 3-6 L of IV fluids per day, depending on clinical condition and response 1
• For severe rhabdomyolysis (CPK >15,000 IU/L), volumes greater than 6 L may be required to prevent acute kidney injury 1

Monitoring Parameters

• Hourly urine output (target: ≥300 mL/hour) 4
• Urine pH (target: 6.5) 1
• Serial measurements of:
  • Plasma myoglobin
  • Creatine phosphokinase (CPK)
  • Potassium
  • Creatinine
  • Acid-base status

Special Considerations

Adjunctive Therapies

• Sodium bicarbonate: The evidence does not support routine use of bicarbonate for all patients with rhabdomyolysis 2

  • Consider only in patients with metabolic acidosis
  • Goal is to maintain urine pH at 6.5 1

• Mannitol: Not routinely recommended based on current evidence 2

  • May be considered only if urine output goals are not achieved with aggressive fluid resuscitation 4

Duration of Therapy

• Continue aggressive IV fluid therapy until CPK levels decrease to less than 1,000 U/L 4
• Adjust fluid rates based on clinical response and laboratory parameters

Contraindications and Cautions

• In patients with traumatic brain injury, maintain normal saline as the fluid of choice 3
• Avoid potassium-containing fluids like lactated Ringer's in the initial management phase 3
• Monitor for signs of fluid overload, especially in patients with cardiac or renal dysfunction
• Be vigilant for compartment syndrome, which may require fasciotomy 1

Pitfalls to Avoid

• Delayed initiation of fluid resuscitation increases risk of acute kidney injury 1
• Inadequate fluid volumes, particularly in severe rhabdomyolysis (CPK >15,000 IU/L) 1
• Failure to monitor electrolytes, especially potassium, which can lead to life-threatening arrhythmias
• Overlooking compartment syndrome, which requires surgical intervention regardless of fluid management 2
• Routine use of bicarbonate or mannitol without clear indications 2

By following this evidence-based approach with normal saline as the primary IV fluid and maintaining adequate urine output through aggressive fluid resuscitation, the risk of acute kidney injury and need for dialysis in rhabdomyolysis can be significantly reduced.