Respiratory Care Safety: Fire, Electrical & Cylinder Hazards

The fire triangle and oxygen as oxidizer

A fire requires three elements: fuel, an ignition source (heat or spark), and an oxidizer. Remove any one and there is no fire. Oxygen is the oxidizer, not the fuel — oxygen itself does not burn, but an oxygen-enriched atmosphere lowers the ignition energy of fuels and makes everything burn faster and hotter. Nitrous oxide (N₂O) also supports combustion.

Home oxygen combined with smoking is the leading cause of home oxygen-therapy burns and fires. In the operating room, oxygen accumulating under surgical drapes is a classic surgical-fire setup. Controlling the oxidizer means no smoking and no open flames near oxygen; keeping oxygen away from heat, sparks, and — critically — from oil and grease, since petroleum products can ignite in high-pressure oxygen. In an oxygen-fed fire, shut off the oxygen source.

Fire-extinguisher classes: A — ordinary combustibles (paper, wood, cloth); B — flammable liquids; C — energized electrical equipment; K — kitchen or cooking media. Multipurpose ABC extinguishers are common throughout hospitals.

Electrical safety: macroshock, microshock, and leakage current

Macroshockis current applied across intact skin or the body surface. At 60 Hz: the perception threshold is roughly 1 mA; the “let-go” current — above which muscle tetany prevents releasing the conductor — is roughly 5–10 mA; and ventricular fibrillation occurs at roughly 100 mA.

Microshockis a small current delivered directly to the myocardium through an intracardiac conductor — a pacing wire, a saline-filled central catheter, or an intracardiac catheter. Because the current is concentrated at the heart rather than spread across the body, as little as ~10 µA (0.01 mA) can trigger ventricular fibrillation. Patients with a direct conductive path to the heart are considered “electrically susceptible.”

Leakage currentis small, unintended stray current that flows from a device’s chassis to ground through imperfect insulation and capacitive coupling — normal in tiny amounts but dangerous if it reaches a microshock-susceptible patient. Standards cap chassis leakage (commonly ≤100–500 µA for general equipment) and hold devices with direct cardiac contact to a far stricter limit, on the order of ≤10 µA.

Controls include proper grounding (three-prong plugs), ground-fault circuit interrupters (GFCIs), routine biomedical inspection, and never using damaged cords or daisy-chained power strips.

RACE — fire response

Rescue anyone in immediate danger — Alarm (pull the alarm and call) — Confine the fire (close doors) — Extinguish if small, or Evacuate. In a respiratory setting, also shut off the oxygen feeding the fire.

PASS — using a fire extinguisher

Pull the pin — Aim at the base of the flames — Squeeze the handle — Sweep side to side.

Cylinder handling and storage

• Secure cylinders upright and chained or carted — a toppled cylinder whose valve shears can rocket.
• Store in a cool, dry, ventilated area away from heat and flammables, below manufacturer temperature limits.
• Separate full cylinders from empty, and separate oxidizers from flammable gases.
• Never apply oil or grease to oxygen fittings.
• “Crack” the valve — briefly open then close, aimed away from people — before attaching a regulator, and open the valve slowly while standing to the side.