Monoplace Delivery System
Monthly Hyperbaric Safety Notice: November 2005
Hyperbaric Gurney Grounding Issue
Background
Elimination of static electricity accumulation is of critical importance to hyperbaric fire safety. Accordingly, the chamber is physically grounded to the hospital grounding system, as is the patient. Conductivity from patient to chamber is achieved via the two brass wheels on the patient gurney.
Safety Issues
During a recent treatment, a patient was about to be placed into the chamber when the staff member sensed a static discharge. A synthetic hair weave was in place on the patient. It was considered the likely point of static accumulation and removed. Investigation as to why static had accumulated, and had not been conducted from the patient through the chamber-to-earth pathway ensued. It became apparent that the two brass (conductive) wheels were outside the chamber while the gurney remained in the fully-withdrawn position. There would be no conduction until one or both of these wheels made contact with the transfer rails inside the chamber, the remaining wheels being plastic (non-conductive).
We discussed this with Sechrist Industries, who were not aware that this situation had arisen in the past. What we are now going to do is switch the position of the brass wheels with those plastic wheels furthest from the head of the gurney. This will effect conduction as soon as the gurney begins its travel into the chamber. Please request the hospital’s Biomedical Department personnel to assist in making this change.
The Bottom Line
The pathway designed to minimize static accumulation within the monoplace chamber requires that the brass gurney wheels are in contact with the chamber support rails. Under the configuration provided by the manufacturer, this does not occur when the gurney is fully or even partially withdrawn. By placing the brass wheels at the opposite end of the gurney, grounding occurs with only minimum advancement of the gurney.
Contributing Author: Dick Clarke, CHT
Dick
is President of National Baromedical Services, which he founded in 1986. His
previous background included service in the British Royal Navy, diving instructor
and underwater photographer, assistant director of the seabed habitat 'HydroLab'
and several years in the offshore commercial diving industry. Dick heads the
Baromedical Research Foundation where he serves as Principal Investigator for
several international clinical trials. He is course director for 'Primary Training
in Hyperbaric Medicine' and the 'HBO 2000' series of advanced hyperbaric symposia.
Dick has been a NOAA Diving Medical Officer Training Course faculty member since
1983. He pioneered the Certification in Hyperbaric Technology (CHT) program,
is a past president of the National Board of Diving and Hyperbaric Medical Technology
and remains active at the committee level within the Undersea and Hyperbaric
Medical Society.
Full Panel of Safety and Technical Correspondents
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