New Minimum Relative Humidity Requirements Are Expected to Lead to More Medical Device Failures
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In 2010, the Addendum D to ASHRAE Standard 170, “Ventilation of healthcare facilities,” lowered the minimum relative humidity (RH) requirement of anesthetizing locations (including operating rooms, operating/surgical cystoscopic rooms, delivery rooms (Caesarean), recovery rooms, critical and intensive care, newborn intensive care, treatment rooms, trauma rooms (crisis or shock), laser eye rooms, newborn nursery suites, and endoscopy rooms) from 30 % to 20 %. The new minimum limit was adopted based on the results of a review paper that suggested that lowering humidity levels will have little or no impact on providing a safe environment for patients, staff, or medical equipment. That review paper reached this conclusion by assuming that there were no medical device failures due to electrostatic discharge (ESD). However, in an examination of the FDA’s MAUDE database of reported defects and recalls, we identified numerous medical device failures explicitly due to ESD. This paper presents technical reliability and safety concerns regarding the new guidelines and recommends that such changes should not be implemented and that the guidelines should be revoked.
KeywordsMedical device failure Electromagnetic compatibility Electrostatic discharge Ventilation Relative humidity
The authors would like to thank the more than 100 companies and organizations that support research activities at the Center for Advanced Life Cycle Engineering (CALCE) at the University of Maryland annually. The authors would especially like to thank Mr. Jeffrey Silberberg and Mr. Sandy Weininger from the FDA’s Center for Devices and Radiological Health, Mr. Andrew Streifel from ASHRAE 170 Standard Committee, and Mr. Jay Hamlin from Medtronic Microelectronics Center, for their time and invaluable assistance, helpful suggestions, and critiques. The research reported herein was partially supported by the NSFC under grant number 71420107023, 71231001 and 71301009.
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Conflicts of Interests
Authors declare no conflicts of interests.
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