Cause of Device-Related Incident
Device factors; External factors; User errors

Clinical Specialty or Hospital Department
Anesthesia; Clinical/Biomedical Engineering; CSR / Materials Management; Obstetrics and Gynecology; OR / Surgery

Device Factors
Device failure

Document Type
Hazard Reports

External Factors
Medical gas and vacuum supplies

Mechanism of Injury or Death
Fire

Support System Failures
*Not stated

Tampering and/or Sabotage
*Not stated

User Errors
Incorrect clinical use

UMDNS
Pneumatic Counterpressure Suits [13-069]; Tourniquets, Pneumatic [14-074]

Inappropriate Use of Oxygen to Inflate or Power Medical Devices



Hazard [Health Devices Dec 1982;12(2):54-5]

Problem

ECRI has long recognized the hazards of inflating pneumatic tourniquets with oxygen (see Health Devices 11:148-9, March 1982 and 10:197, June 1981). We have learned that some emergency medical service (EMS) personnel use or are considering use of oxygen as the inflation gas for antishock trousers and as the driving gas for pneumatic-powered devices being developed to enhance the effectiveness of cardiopulmonary resuscitation (CPR).

Our past investigations of oxygen fires involving medical devices (see Health Devices 9:50 and 82, December 1979 and January 1980) lead us to be extremely concerned about the use of oxygen for such devices. We believe that such use poses a significant fire hazard and we recommend against it. We also recommend against the use of nitrous oxide in such devices since it supports combustion as well as oxygen does. In addition, the risks of repeated personnel exposure to nitrous oxide exist unless the device is scavengeable.

If filled with oxygen or nitrous oxide, medical devices and their tubing can ignite and burn violently upon contact with any of the ignition sources present in the operating room (e.g., electrosurgical units, battery- and AC-powered electrocautery units, surgical lasers, fiberoptic light sources), the emergency room (e.g., defibrillators, high-intensity examination lamps), or the prehospital setting (e.g., defibrillators, cigarettes, matches, floating ash or embers from a fire).

Discussion

Oxygen is used or considered for use as an inflating gas because of its convenient presence in the healthcare setting. Similarly, nitrous oxide is conveniently available in the OR and emergency department and is being used more frequently in the prehospital setting combined with oxygen as an analgesic. However, other gases are also conveniently available and are more suitable for pneumatic-powered devices that are not intended for therapeutic oxygen administration. These include air (supplied by manual pump, or compressed air outlet or cylinder) or noncombustible gases such as nitrogen (from a compressed gas cylinder) or Freon (from a disposable canister).

The increased flammability of an oxygen-filled device can be dramatic. We conducted flammability tests during our evaluation of antishock trousers (Health Devices, 6:265-77, August-September 1977) and found that the polyurethane-coated nylon fabric used in their construction is slow-burning National Fire Protection Association (NFPA) NFPA Class 1 Standard material (i.e., took more than 19 seconds for the flame to spread over a six-inch test sample). These tests were conducted with air, in accordance with NFPA 702-1975, Standard for Classification of the Flammability of Wearing Apparel.

We retested the burning characteristics of antishock trousers. After inflating leg sections with oxygen, we placed a lighted paper match on the surface of the trouser material over the center of the bladder. We repeated this test when the trousers were inflated with air. We then calculated the amount of material burned per unit time. Our tests indicated that the flame spread rate of oxygen-filled trousers was more than 150 times faster than that of air-filled trousers.

In addition, oxygen that leaks or is vented from oxygen-filled or -powered devices can build up beneath surgical drapes or ambulance cot blankets and cause other materials to ignite easily and burn violently. (Also, fabrics, plastics, and rubber deteriorate much more rapidly in oxygen- or nitrous oxide-enriched environments.) In one incident reported to us, a disconnected fiberoptic cable ignited a disposable nonwoven surgical drape that had trapped oxygen beneath it (Health Devices, 11:148-9, March 1982). The oxygen had leaked from a faulty inflation connector of a surgical pneumatic tourniquet. The resulting flash fire severely burned the patient's legs.

Recommendations

  1. Do not use oxygen or nitrous oxide to inflate or power pneumatic devices that do not administer oxygen therapeutically.
  2. If you suspect that oxygen has been used as the inflating gas, use extreme care to prevent possible ignition sources from contacting the device. Likely ignition sources include electrosurgical units, electrocautery units (both battery- and AC-powered), fiberoptic light sources, surgical lasers, defibrillators, and high-intensity examination lamps.
  3. Discontinue use of surgical pneumatic tourniquets inflated by oxygen. Contact the manufacturer for information about adapting the tourniquet for use with other gases. Purchase only tourniquets inflated by air, nitrogen, Freon, or other noncombustible gas. If an oxygen-inflated tourniquet must be used until a replacement is obtained or modified, follow Recommendation 2.
  4. Manufacturers of pneumatic-powered devices not intended to deliver oxygen therapy should label their equipment cautioning against the use of oxygen for inflation. Where possible, the device should be designed to prevent the use of compressed oxygen from either a gas cylinder or wall outlet.

UMDNS Terms

  • Pneumatic Counterpressure Suits [13-069]
  • Tourniquets, Pneumatic [14-074]

Cause of Device-Related Incident

Device factor: Device failure 

User error: Incorrect clinical use

External factor: Medical gas and vacuum supplies

Mechanism of Injury or Death

Fire


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