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Question

Difficulty: HardInitial Stabilization and Triage

A 42-year-old male construction worker is brought to the emergency department by paramedics after being extricated from beneath a collapsed concrete retaining wall, where he was trapped for approximately seven hours. Upon arrival, the patient is somnolent and weakly responsive to painful stimuli. His bilateral lower extremities are severely swollen, ecchymotic, and tense to palpation, with absent pedal pulses. Vital signs reveal a blood pressure of 82/48 mm Hg, a heart rate of 52/min, a respiratory rate of 22/min, and an oxygen saturation of 95% on supplemental oxygen. A stat 12-lead electrocardiogram demonstrates absent P waves, markedly widened QRS complexes, and tall, peaked T waves. Which of the following is the single most urgent initial step in the stabilization of this patient?

  1. Administration of intravenous calcium chlorideAnswer
  2. B
    Administration of intravenous regular insulin and dextrose
  3. C
    Computed tomography angiography of the bilateral lower extremities
  4. D
    Immediate transfer to the operating room for bilateral fasciotomies
  5. E
    Emergent consultation with nephrology for continuous venovenous hemofiltration

Answer

Administration of intravenous calcium chloride
The correct answer is the administration of intravenous calcium chloride. This patient has crush syndrome resulting in massive rhabdomyolysis and severe hyperkalemia, as evidenced by his bradycardia and classic electrocardiogram (ECG) changes (absent P waves, widened QRS complexes, peaked T waves). When hyperkalemia causes wide QRS complexes, the patient is on the verge of fatal ventricular arrhythmias or asystole. The most urgent initial stabilization step is the administration of intravenous calcium (either chloride or gluconate) to antagonize the membrane actions of potassium and stabilize the resting membrane potential of the cardiomyocytes. This buys time for subsequent therapies that actually lower serum potassium levels.

Step-by-Step Solution

1
Analyze the patient's mechanism of injury and clinical presentation.
The patient experienced a prolonged crush injury (seven hours), placing him at extremely high risk for severe rhabdomyolysis and subsequent electrolyte derangements.
Crush syndrome leads to massive muscle cell death, releasing intracellular contents such as potassium, myoglobin, and creatine kinase into the systemic circulation.
2
Interpret the vital signs and electrocardiogram (ECG) findings.
The patient is hypotensive and bradycardic. The ECG shows absent P waves, widened QRS complexes, and peaked T waves.
These specific ECG abnormalities are the hallmark of severe, life-threatening hyperkalemia approaching a sine-wave pattern, indicating imminent cardiac arrest.
3
Determine the highest priority initial stabilization step.
Myocardial membrane stabilization must be achieved immediately using intravenous calcium (chloride or gluconate).
In the initial triage and stabilization phase, preventing cardiac arrest takes precedence over definitive surgical management of compartment syndrome, diagnostic imaging, or subacute potassium-shifting therapies.

Key Concept

In patients with severe hyperkalemia demonstrating electrocardiographic changes (e.g., widened QRS, absent P waves), the absolute first priority in stabilization is the administration of intravenous calcium to stabilize the myocardial membrane.
Estimated Time:1m 30s
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Topics

Initial Stabilization and Triage

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