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Surgeons' Lounge: Relative Humidity Levels
Dangers of Letting OR Humidity Dip Below 30%
Kendal Gapinski
Publish Date: February 4, 2015   |  Tags:   Patient Safety

RELATIVE HUMIDITY LEVELS
Dangers of Letting OR Humidity Dip Below 30%

You could be jeopardizing patient safety if you keep the humidity level in your ORs too low. As you may know, the American Society of Heating, Refrigeration and Air Conditioning Engineers lowered the allowable lower humidity parameter for operating rooms from 30% to 20% in 2013. But now comes a warning that relative humidity levels lower than 30% can impact the integrity and functionality of some sterile supplies and electrosurgical equipment.

"The lower [humidity] level can actually harm the integrity of the products [you] use," says the multisociety warning (tinyurl.com/n75mzyq).

  • Sterile supplies. Relative humidity can impact the shelf life and product integrity of sterile supplies. Some products, such as biological indicators and chemical indicators used for sterilization monitoring and EKG electrodes used for patient monitoring, call for a humidity level of 30% or higher and are very sensitive to humidity, says the warning, noting that EKG electrodes are in foil pouches primarily to protect against changes in external humidity levels.
  • Electrosurgical equipment. Relative humidity may affect the operation of some electrosurgical equipment, particularly causing older equipment to malfunction unexpectedly. Too-low humidity levels may also impact calibration. And in an environment where humidity is low, a person can more easily become "charged" and receive an electrostatic shock when coming in contact with medical equipment.

Check manufacturers' recommendations for humidity in areas where you store and use medical supplies and electrical equipment, says Ramona Conner, MSN, RN, CNOR, editor-in-chief of AORN's Guidelines for Perioperative Practice. If you decide to maintain humidity levels below 30%, consider moving supplies that call for humidity levels of 30% or higher to a humidity-controlled closet, she adds.

— Kendal Gapinski

EDITOR'S NOTE: We originally stated that the Association for the Advancement of Medical Instrumentation lowered the allowable low humidity parameter for operating rooms from 30% to 20% in 2013. In fact, it was ASHRAE (the American Society of Heating, Refrigeration and Air Conditioning Engineers) who lowered the standard. The Association for the Advancement of Medical Instrumentation instead issued a multi-society statement warning about the effects the lowered levels could have on medical instruments and supplies. We apologize for the error.

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