Microshock Current — FRCA Primary MCQ

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ModeratePhysics & Clinical MeasurementMicroshock CurrentFRCA Primary

Microshock can cause ventricular fibrillation at currents as low as:

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Correct answer: E — 50-100 μA

Microshock: 50-100 μA directly to the myocardium (via pacemaker wire / central line / intracardiac catheter) can cause VF. Macroshock requires ~100 mA externally to cause VF. This distinction is critical for electrical safety around patients with intracardiac devices.

Reference: Al-Shaikh Stacey 2019 Essentials of Anaesthetic Equipment