Hypocalcaemia ECG Changes — FRCA Final MCQ

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EasyGeneral AnaesthesiaHypocalcaemia ECG ChangesFRCA Final

A 50-year-old woman (ASA II) undergoing total thyroidectomy develops a seizure in recovery. Her corrected calcium is 1.55 mmol/L. Which ECG change is characteristically seen in hypocalcaemia?

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Correct answer: A — Prolonged QT interval

Hypocalcaemia characteristically causes QT prolongation on ECG due to prolongation of the ST segment (the QTc is lengthened). This increases the risk of torsades de pointes. Other ECG changes include: T wave changes (flattened or inverted). Clinical features of severe hypocalcaemia include: paraesthesiae, carpopedal spasm (Trousseau sign), facial twitching (Chvostek sign), laryngospasm, bronchospasm, seizures, and cardiac arrest. Treatment: 10 mL 10% calcium gluconate IV over 10 minutes, repeated as needed, followed by an infusion.

Reference: RCOA – 2023 – Final FRCA curriculum: electrolyte physiology; Resuscitation Council UK – 2021