A 68-year-old man with CKD stage 5 on spironolactone and lisinopril presents to the emergency department with palpitations and weakness. His serum potassium is 8.2 mEq/L. The ECG shows the pattern marked **A** in the diagram. Which of the following is the MOST APPROPRIATE immediate management?
A. Intravenous calcium gluconate 10% 10 mL over 2–3 minutes
B. Oral patiromer 8.4 g daily
C. Sodium bicarbonate 50 mEq IV bolus
D. Regular insulin 10 units IV with 25 g dextrose
Explanation
Why Intravenous calcium gluconate 10% 10 mL over 2–3 minutes is right
The pattern marked A — the sine wave — is the TERMINAL ECG MANIFESTATION of severe hyperkalemia (K+ >7.5–9 mEq/L) and represents fusion of a markedly widened QRS complex with the broadened T wave into a continuous sinusoidal waveform. This pattern IMMEDIATELY PRECEDES VENTRICULAR FIBRILLATION OR ASYSTOLE and is a MEDICAL EMERGENCY. The FIRST and ONLY step in management of sine wave hyperkalemia is to STABILIZE THE CARDIAC MEMBRANE immediately with IV calcium gluconate (or calcium chloride via central line), which has an onset of <3 minutes and duration of 30–60 minutes. Calcium does NOT lower serum potassium but protects the myocardium from dysrhythmia and cardiac arrest. This patient with K+ 8.2 mEq/L and a sine wave pattern is in peri-arrest and requires calcium FIRST before any other intervention (KDIGO 2024; ACLS; UpToDate Hyperkalemia).
Why each distractor is wrong
Regular insulin 10 units IV with 25 g dextrose: While insulin-dextrose is a critical second-line agent that shifts potassium intracellularly (onset 15–30 min, duration 4–6 h) and lowers K by ~1 mEq/L, it is NOT the first intervention in sine wave hyperkalemia. Calcium must be given FIRST to stabilize the membrane and prevent immediate cardiac arrest; insulin is given AFTER calcium.
Sodium bicarbonate 50 mEq IV bolus: Bicarbonate is reserved ONLY for severe metabolic acidosis (pH <7.2) and is NOT a first-line agent for sine wave hyperkalemia in the absence of acidosis. It is slower and less effective than insulin-dextrose and plays no role in acute membrane stabilization.
Oral patiromer 8.4 g daily: Patiromer is a chronic oral cation exchanger used for maintenance management of hyperkalemia in stable CKD patients, NOT for acute life-threatening hyperkalemia with a sine wave pattern. It has a slow onset (hours to days) and is contraindicated in peri-arrest scenarios.
High-YieldNEET PG
Sine wave = peri-arrest; calcium FIRST (onset <3 min); insulin-dextrose second (onset 15–30 min); dialysis for refractory cases.
KDIGO 2024; ACLS; UpToDate Hyperkalemia
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