Diagnosis from ECG Findings

The electrocardiogram (ECG) findings described are characteristic of hyperkalemia (high potassium levels):

• Peaked T waves: Indicate impaired ventricular repolarization.
• Prolonged PR interval: Suggests slowed conduction through the atrioventricular (AV) node.
• Widened QRS complexes: Reflect slowed conduction through the ventricles, potentially leading to arrhythmias.

Crushing injuries can lead to rhabdomyolysis and subsequent release of intracellular potassium, causing hyperkalemia.

Hyperkalemia Treatment Rationale

Immediate treatment for severe hyperkalemia with ECG changes focuses on two main goals: stabilizing the cardiac membrane and shifting potassium into cells.

• Sodium bicarbonate infusion: This treatment is indicated for hyperkalemia, particularly when accompanied by metabolic acidosis (common after crushing injuries) or significant ECG abnormalities. Sodium bicarbonate helps stabilize the cardiac cell membrane, counteracting the effects of high potassium. It can also facilitate the movement of potassium into cells.

Evaluating Other Treatment Options

The other options are less appropriate for the immediate management of hyperkalemia with these ECG changes:

• Intravenous bolus procainamide: While a medication affecting cardiac conduction, it is not a primary treatment for hyperkalemia and can sometimes worsen conduction delays.
• Insulin infusion: Insulin (usually given with glucose to prevent hypoglycemia) is a primary treatment for shifting potassium into cells, but sodium bicarbonate is often prioritized for membrane stabilization, especially if acidosis is present.
• Intravenous magnesium sulphate: Magnesium is primarily used for conditions like Torsades de Pointes or hypomagnesemia, not typically as a first-line treatment for hyperkalemia-induced ECG changes.

Therefore, sodium bicarbonate infusion is the most appropriate immediate treatment among the choices provided for a patient with crushing injury and ECG changes suggestive of hyperkalemia.