“With this and
with increasing explosions in hospital operating rooms and
in chemical and pharmaceutical laboratories, people called
the cause of these explosions static electricity.” Niels
Jonassen, MS, DSc, Technical University of Denmark, Retired
Hazards in the Operating
Room
A potential hazard in operating
rooms is associated with the mixture of anesthetic gases with
oxygen or air. Extensive field and laboratory investigations
have been carried out, notably by the U.S. Bureau of Mines,
demonstrating conclusively that mixtures of oxygen or air
with anesthetic gases normally used in operating rooms can
be ignited by very low energy sources; energies in excess
of this minimum are associated with spark discharges such
as are produced from electrostatic charges built up on equipment
and personnel in operating rooms. This constitutes the chief
source of ignition, although other sources such as open flames,
arcs and sparks from non-explosion-proof electrical equipment
and faulty wiring, as well as incandescent lamps and endoscopes
or high frequency cauteries or coagulators have added to the
hazard.[3]
With technologically advanced hospital
monitoring equipment, lock ups and ESD related failures are
possible. Unexplained equipment fluctuations observed by surgeons[4] have occurred in hospital environments. Some hospital organization’s
specifications have been observed to call out Electrostatic
Propensity or carpets to be less than 2.0 KV ( charge generation
in combination with a person.
This specification is extremely high
and above the requirement for charge generation in combination
with a conductive floor and person. For example, a surgeon
walking across a carpet could compromise an ESD medical device.
Moreover, a medical device, although properly stored for ESD
protection, could be removed from the package, then tribocharged
before installation. To create an ESD event three things are
necessary:
- Charge Generation
- Charge Accumulation
- Rapid Discharge
ESD sensitive microprocessor
driven technology such as pacemakers would fall within the
ESD Roadmap in Figure 3 below.
1Lt. Brenda Shealy checks
a piece of anesthesia equipment in an operating room during
Operation Desert Shield.
2Captain Cynthia Warwick (right) and Staff Sergeant
Chad Smith, USAF, prepare a syringe with local anesthesia
during Operation Enduring Freedom.
3CBD-32. Safety from Fires and Explosions in Hospital
Operating Rooms, P. J. Sereda 1962
4Conversations with Doug Vermillion, MD, Fellow
US Army Orthopedic Surgeon (Ret)
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