A patient with end-stage renal disease on haemodialysis is receiving succinylcholine for rapid sequence intubation. The serum potassium measured 4 h after the last dialysis session is 5.1 mEq/L. What is the expected rise in serum K+ after succinylcholine administration?

• A 0.1–0.2 mEq/L — same as in a normal patient
• B 1.0–2.0 mEq/L due to upregulated extrajunctional receptors
• C 4–5 mEq/L because haemodialysis potentiates depolarising blockade
• D 0.5 mEq/L — the standard rise seen in all patients ✓

Explanation

In chronic renal failure without denervation injury or burns, succinylcholine causes the same 0.5 mEq/L rise in K+ as in a normal patient, making it safe when pre-dialysis K+ is ≤5.5 mEq/L. Dangerous hyperkalaemia (1–2+ mEq/L rise) occurs only when there is upregulation of extrajunctional ACh receptors due to denervation, immobilisation, burns, prolonged ICU stay, or crush injury — not simply from CKD alone.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

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