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Operating Theater Fumigation: Complete Procedure Guide

OT Fumigation Protocol: Step-by-Step

Fumigation (formaldehyde vapor or hydrogen peroxide vapor) reduces microbial load to near-sterile levels. Strict adherence protects staff and patients.

Phase 1: Preparation

  1. Seal the OR: Close and lock all doors; post "Fumigation in Progress" signs.
  2. Remove sensitive items: Instruments, electronics, monitors, disposable supplies, medications. Cover fixed equipment with impermeable drapes.
  3. Seal penetrations: Tape door gaps, HVAC vents, pass-throughs, light fixtures with polyethylene sheeting and duct tape.
  4. Place fumigant generators: Per manufacturer's layout (e.g., paraformaldehyde pellets in electric vaporizers or H₂O₂ cartridges in vaporizer units).
  5. Verify humidity/temperature: Formaldehyde requires >60% RH and >20°C; H₂O₂ systems have specific parameters.

Phase 2: Fumigation

  1. Activate generators remotely or via timed release.
  2. Evacuate immediately: All personnel exit; secure the room.
  3. Monitor concentration (optional): Real-time sensors confirm target ppm (e.g., 800–1000 ppm formaldehyde).

Phase 3: Aeration and Decontamination

  1. Wait prescribed contact time: Typically 6–12 hrs (formaldehyde); 2–4 hrs (H₂O₂ vapor).
  2. Shut off HVAC before entry to prevent contaminant spread.
  3. Ventilate: Open doors/windows; run dedicated exhaust fans. Use PPE (N95/PAPR, gloves, goggles).
  4. Neutralize (formaldehyde): Ammonia vapor or sodium bisulfite spray per manufacturer.
  5. Air clearance testing: Formaldehyde <0.1 ppm; H₂O₂ <1 ppm before re-entry.

Phase 4: Restoration and Validation

  1. Terminal cleaning: All surfaces with EPA-registered disinfectant.
  2. HEPA vacuum if particulate residue suspected.
  3. Environmental cultures (optional): Settle plates, swabs for QC.
  4. Reinstall equipment after wipe-down.
  5. Final sign-off: Infection control/ICU nurse manager approves reopening.

Critical Safety Notes

  • Formaldehyde is a carcinogen (IARC Group 1); H₂O₂ vapor is safer but requires material compatibility checks.
  • Never enter during fumigation or before clearance testing.
  • Document every step: date, time, agent, lot #, personnel, test results.

Schedule fumigation during low-utilization periods (weekends, nights) and coordinate with OR scheduling, engineering, and infection prevention.

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