ICU · equipment-physics

ICU Electrical Safety — Comprehensive (Macroshock, Microshock, Equipotential Bonding)

Also known as Electrical safety · Macroshock · Microshock · Equipotential bonding · Isolated power supply · Leakage current · Cardiac floating equipment · Type CF equipment · Diathermy safety

ICU electrical safety — the principles and precautions to prevent electrical injury to patients and staff. Two types of electrical hazard: MACROSHOCK (external current passes through intact skin → body acts as volume conductor → current spreads → VF if 100 mA reaches the heart — prevented by grounding, RCDs, double insulation) and MICROSHOCK (tiny current ~10-100 μA applied DIRECTLY to the heart via a conductive pathway — central line, pacing wire, saline column → VF at 1000x lower threshold than macroshock — the KEY danger in ICU and cardiac areas). Prevention: EQUIPOTENTIAL BONDING (all conductive surfaces connected to same ground potential → no voltage difference → no current through patient), ISOLATED POWER SUPPLY (IPS — transformer isolates supply from ground → no path for leakage current → eliminates macroshock), EQUIPMENT CLASSIFICATION (Type CF — cardiac floating — leakage <10 μA — safe for direct cardiac connection; Type BF — body floating — safe for external use; Type B — basic — NOT cardiac-safe). Leakage current monitoring: all ICU equipment must be tested annually for leakage (<500 μA for chassis leakage, <10 μA for patient leads in CF equipment).