Cause of Device-Related Incident
Device factors; Support system failures; User errors

Clinical Specialty or Hospital Department
CCU / ICU / NICU; Clinical/Biomedical Engineering; Emergency Medicine; Nursing; Pulmonary / Respiratory Therapy

Device Factors
Design / labeling error; Improper maintenance, testing, repair, or lack or failure of incoming inspection; Improper modification; Invalid device foundation

Document Type
Hazard Reports

External Factors
*Not stated

Mechanism of Injury or Death
Barotrauma; Failure to deliver therapy; Suffocation

Support System Failures
Failure to train and / or credential; Lack or failure of incoming and pre-use inspections

Tampering and/or Sabotage
*Not stated

User Errors
Failure to perform pre-use inspection; Incorrect clinical use

UMDNS
Resuscitators, Pulmonary, Gas Powered [13-366]

Gas-Powered Resuscitators



Hazard [Health Devices Nov 1988;17(11):352-4]

Problem

For nearly 30 years, ECRI has followed the development of gas-powered resuscitators and contributed to their improvement by conducting formal evaluations, investigating reports of problems, participating in standards development, and educating users. Unfortunately, injuries and deaths related to malfunction, misassembly, poor maintenance, and misuse of gas-powered resuscitators continue to occur.

Continuing reports of incidents with these devices prompted us to write this hazard report, which summarizes associated risks, provides new performance criteria, and updates related Inspection and Preventive Maintenance System procedures for gas-powered resuscitators.

Discussion

Gas-Powered Resuscitator Operation

Manually triggered, pressure-limited gas-powered resuscitators are intended primarily for positive pressure ventilation with 100% oxygen during cardiopulmonary resuscitation (CPR). The resuscitators are powered from a 50 psi oxygen source and connect to standard 15 and 22 mm breathing circuit fittings of face masks and endotracheal tubes. These units are designed to provide high flow rates to ensure rapid lung inflation, based on performance requirements established when lungs were inflated between each cardiac compression. To deliver high flows of oxygen to the patient, the operator simply depresses a button or lever on the resuscitator. Resuscitators are designed to limit pressure to prevent pulmonary barotrauma.

Most gas-powered resuscitators used in the United States also operate in a Demand mode, in which the unit automatically delivers oxygen flow proportional to the patient's inspiratory efforts; such units are often referred to as oxygen demand valves. In this mode, the resuscitator provides 100% oxygen for conscious, spontaneously breathing patients (e.g., victims of carbon monoxide poisoning). Other gas-powered resuscitators provide a user-adjustable controlled flow of oxygen for spontaneously breathing patients. This feature allows the operator to vary flow, depending on patient needs, much like a flowmeter.

Associated Risks

Gas-powered resuscitators are superior to manual resuscitators because they can deliver 100% oxygen and require little exertion to ventilate the patient. During extended resuscitation efforts with bag-mask units, performance often deteriorates as the operator becomes fatigued by squeezing the bag and holding the mask and resuscitator, which can prevent effective patient ventilation. However, gas-powered resuscitators, which do not use a bag, do not limit volume or allow the operator to feel when the patient's lungs are fully inflated. The operator must determine when to stop delivering oxygen by watching the patient's chest expand. If a gas-powered resuscitator fails to properly limit pressure, the patient can be seriously injured before the operator is aware that a malfunction has occurred.

The risk of patient injury from a malfunctioning unit can be minimized by testing it before use. Typical equipment abuses (e.g., dropping) that occur during emergencies, whether in the field or the hospital, can damage a resuscitator. Each time a unit is cleaned, disinfected, and reassembled, it must be inspected to confirm that it operates properly.

Performance Standards

In our 1978 evaluation of gas-powered resuscitators (Health Devices 8:24-38, December 1978), both ECRI and the American Heart Association (AHA) recommended that 60 cm H2O be the maximum acceptable pressure and 100 L/min be the minimum acceptable flow. Flows of 100-200 L/min were considered necessary to fully inflate a victim's lungs between chest compressions during CPR (as performed at that time) and to compensate for leakage from the mask. When used with a face mask rather than an endotracheal tube, the high flow of these devices often inflated the victim's stomach, and use of endotracheal tubes was strongly recommended to avoid stomach inflation, vomiting, and aspiration of vomitus.

Experience and studies have shown that insufflation of a tidal volume between each chest compression during CPR is not necessary. Thus, the high flow rate requirement is no longer needed, and recent standards for CPR reflect this. In 1986, the AHA recommended that the maximum oxygen flow from these devices not exceed 40 L/min and that the outlet pressure not exceed 60 cm H2O (44 mm Hg). In addition, the AHA recommended that these devices not be used on small children or infants. ECRI concurs with these recommendations and suggests that users familiarize themselves with the most recent draft of the standard (see JAMA 1986; 255(21):2905-2989).

Gas-powered resuscitators that conform to the new standard will inflate patients' lungs more slowly and are less likely to force oxygen into the GI tract. Slower inflation also gives the operator more time to observe chest expansion and react accordingly before maximum outlet pressure is transmitted to the patient's lungs. Therefore, resuscitators with a 40 L/min maximum flow should be less likely to cause pulmonary barotrauma and gastric distention.

We encourage all healthcare facilities and emergency medical services to have modifications made during routine servicing and replace units only with low-flow units.

Recommendations

  1. Use gas-powered resuscitators with great care. Do not use gas-powered units on infants or small children. Operators who are unlikely to be able to maintain an airway using a manual resuscitator (e.g., because of small hand size, fatigue, or space constraints) should use gas-powered resuscitators. The operator must decide this based on his or her skill with each type of device and the specific needs of the patient. Also, gas-powered resuscitators with demand valve capability are preferable for treating conscious patients (e.g., victims of carbon monoxide poisoning).
  2. Immediately place all gas-powered resuscitators on a routine inspection and preventive maintenance schedule. (See our Inspection and Preventive Maintenance System procedure for Gas-Powered Resuscitators.)
  3. Return those units with a flow rate that exceeds 40 L/min to the manufacturer for a low-flow modification when due for inspection and preventive maintenance. Be sure to contact the manufacturer before returning a resuscitator to arrange shipping and service details. Hospital personnel should never attempt to disassemble or modify the flow control of a gas-powered resuscitator without written approval and instructions from the manufacturer. All low-flow versions should be clearly marked with the maximum flow (e.g., max flow: 40 L/min) to distinguish them from earlier high-flow versions. Inform users that these devices will not inflate the lungs as rapidly as earlier versions, and explain the reason for this change.
  4. According to manufacturers' recommendations, clean and disinfect the washable parts of resuscitators after each use. Verify proper operation of the units after each cleaning and reassembly. Seal the resuscitator in a clean plastic bag, where it will be protected until needed.
  5. Verify that all personnel using gas-powered resuscitators are trained in their use, and update the training periodically. Training should include simulated resuscitator malfunctions (e.g., no oxygen flow, patient airway occlusion).
  6. When purchasing new units, buy only those units that conform to the 40 L/min recommended maximum flow.

UMDNS Term

Resuscitators, Pulmonary, Gas Powered [13-366]

Cause of Device-Related Incident

Device factors: Design/labeling error; Improper maintenance, testing, repair, or lack or failure of incoming inspection; Improper modification; Invalid device foundation

User errors: Failure to perform pre-use inspection; Incorrect clinical use

Support system failures: Failure to train and/or credential; Lack or failure of incoming and pre-use inspections

Mechanism of Injury or Death

Barotrauma; Failure to deliver therapy; Suffocation


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