Hazard [Health Devices Nov 1988;17(11):352-4]
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 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
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
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
- 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).
- Immediately place all gas-powered resuscitators on a routine inspection
and preventive maintenance schedule. (See our Inspection and Preventive Maintenance
procedure for Gas-Powered Resuscitators.)
- 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
- 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
- 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).
- When purchasing new units, buy only those units that conform to the 40
L/min recommended maximum flow.
Resuscitators, Pulmonary, Gas Powered [13-366]
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