Aorn Humidity Guidelines ((free)) Review
| Parameter | AORN Guideline | |-----------|----------------| | | 20–60% relative humidity | | Action threshold (low) | <20% for 15+ min | | Action threshold (high) | >60% for 15+ min | | Monitoring | Continuous, visible in OR | | Evidence basis | SSI prevention, infection control, equipment safety |
AORN removed the previous recommendation for a lower limit of 30% or 35% due to lack of evidence linking 20–30% RH to increased SSIs. aorn humidity guidelines
| Issue | Potential Cause | Action | | :--- | :--- | :--- | | | HVAC humidifier malfunction; Outside air is extremely dry (winter). | Activate humidification systems; Check for leaks in the room envelope. | | Humidity too high (>60%) | HVAC chiller failure; Moisture intrusion; Too many people in the room. | Check air handler status; Reduce room occupancy if possible; Verify supply air temperature. | | Fluctuating Readings | Sensor calibration error. | Recalibrate sensors; Replace sensors if readings drift consistently. | | | Humidity too high (>60%) | HVAC
rationale
Many older medical devices were manufactured with a recommended humidity floor of 30%. However, most modern manufacturers have updated their device specifications to tolerate 20% RH. If your facility uses legacy equipment, you must check the manufacturer's instructions for use (IFU); if they require 30%, you must maintain a higher humidity level than the AORN baseline. | Recalibrate sensors; Replace sensors if readings drift
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