When should bicarbonate and calcium be administered in patients with crush injuries?

From the Guidelines

Bicarbonate and calcium should be provided in crush injuries when there is evidence of symptomatic hypocalcemia, severe hyperkalemia with ECG changes, or metabolic acidosis, as these conditions can lead to significant morbidity and mortality if left untreated. The administration of bicarbonate and calcium in crush injuries is a topic of ongoing debate, with some studies suggesting that these interventions may not be beneficial in all cases 1. However, in patients with symptomatic hypocalcemia, severe hyperkalemia with ECG changes, or metabolic acidosis, the use of bicarbonate and calcium can be lifesaving.

Indications for Bicarbonate and Calcium Administration

• Symptomatic hypocalcemia
• Severe hyperkalemia with ECG changes
• Metabolic acidosis (pH < 7.2)

Recommended Dosing

• Sodium bicarbonate administration is recommended when patients develop metabolic acidosis or hyperkalemia, typically given as an IV infusion of 1-2 mEq/kg in D5W solution over 1-2 hours 1
• Calcium gluconate (10%) 10-20 mL or calcium chloride (10%) 5-10 mL IV should be administered when there is symptomatic hypocalcemia, severe hyperkalemia with ECG changes, or to counteract the effects of hyperkalemia on cardiac conduction 1

Rationale

The use of bicarbonate and calcium in crush injuries is supported by recent studies, including a 2023 guideline on the management of major bleeding and coagulopathy following trauma, which highlights the importance of correcting hypocalcemia promptly to prevent cardiac dysrhythmias and other complications 1. Additionally, a 2014 study on disaster nephrology notes that bicarbonate-containing fluids may be beneficial in preventing heme pigment nephropathy, although the evidence is not yet conclusive 1.

Monitoring and Maintenance

• Fluid resuscitation with normal saline should be initiated simultaneously at 10-15 mL/kg/hour to maintain urine output at 1-2 mL/kg/hour
• Electrolytes should be monitored frequently to guide ongoing therapy
• Urine pH should be maintained above 6.5 to prevent myoglobin precipitation in renal tubules 1

From the FDA Drug Label

In metabolic acidosis associated with shock, therapy should be monitored by measuring blood gases, plasma osmolarity, arterial blood lactate, hemodynamics and cardiac rhythm. The amount of bicarbonate to be given to older children and adults over a four-to-eight- hour period is approximately 2 to 5 mEq/kg of body weight - depending upon the severity of the acidosis as judged by the lowering of total CO2 content, blood pH and clinical condition of the patient.

Bicarbonate should be provided in crush injuries when there is metabolic acidosis associated with shock. The dose is approximately 2 to 5 mEq/kg of body weight over a period of 4 to 8 hours, depending on the severity of the acidosis.

• The therapy should be monitored by measuring blood gases, plasma osmolarity, arterial blood lactate, hemodynamics and cardiac rhythm.
• There is no direct information in the provided drug labels about the administration of calcium in crush injuries. 2

From the Research

Crush Injuries and the Role of Bicarbonate and Calcium

• Crush injuries can lead to various complications, including hypovolemia, compartment syndrome, rhabdomyolysis, electrolyte and acid-base imbalances, coagulopathy, and renal failure 3
• The management of crush injuries should focus on minimizing further complications through accurate assessment and therapeutic interventions 3
• Emergency clinicians play a crucial role in the evaluation and treatment of crush injuries, and care at the incident scene is essential, including treating life-threatening injuries, extrication, triage, fluid resuscitation, and transport 4

Timing of Bicarbonate and Calcium Administration

• There is no direct evidence in the provided studies on the specific timing of bicarbonate and calcium administration in crush injuries
• However, the studies emphasize the importance of vigilant prehospital emergency care to reduce complications, including hyperkalemia and acute renal failure 5
• The use of tourniquets in the prehospital setting is recommended for severe crush injuries to prevent hyperkalemia and the release of toxic metabolites into the circulation 5

Electrolyte Imbalances and Crush Injuries

• Hyperkalemia is a life-threatening complication of crush injuries, and providers need to be aware of this risk in the field 5
• The management of electrolyte imbalances, including hyperkalemia, is crucial in the treatment of crush injuries, but the specific role of bicarbonate and calcium is not addressed in the provided studies 4, 5