Concentration Calibrated Vaporizers
Hazard [Health Devices Mar-Apr 1987;16(3-4):112]
During the last few years, ECRI has
investigated or become aware of a number of hazards involving calibrated
vaporizers produced by several manufacturers.(1,2,3,4)
In one case that ECRI investigated, a vaporizer had apparently been dropped. Other cases
reported in the literature involved vaporizers that had been tipped, permitting the agent
to get into upper gas passages.
In each of these hazards, the vaporizers were disconnected from an
anesthesia machine. Several caused severe injury or death. All hazards could have been
detected by testing the vaporizers for proper operation after reattaching them to their
machines. During the same period, ECRI encountered no hazards with vaporizers that
remained mounted on machines. The reported problems involving wear and tear could all have
been detected by regular inspections and preventive maintenance.
Vaporizers should not be removed from anesthesia units unless servicing is
absolutely necessary. This restriction would also eliminate the common practice of
exchanging vaporizers between machines or between a hanger (for an unused vaporizer) and a
working position on the back bar of a machine.
- Purchase enough vaporizers for each machine to
offer a selection of agents appropriate to the hospital's needs.
- Mount all vaporizers in a selector-valve system
(available from most manufacturers) so that none will have to be removed to
enable isolation and use of one of the others.
- Whenever a vaporizer is removed for any reason (e.g., to return it to
the manufacturer for repair or overhaul and calibration), handle or pack it carefully and
avoid tipping (unless it is packed dry for shipping) or entry of foreign substances. If
shipped, pack it in a manner that will minimize the effects of shock and vibration. Then,
when it is reinstalled, test it for leaks and correct output as described in ECRI's Inspection
and Preventive Maintenance System procedures for
anesthesia units and vaporizers. In an emergency, when a halogenated agent
analyzer is not available, use the methods in ECRI's Anesthesia Pre-Use
- ECRI. Water entered a vaporizer and caused corrosion. Health Devices
- ECRI. A vaporizer mounting plate was not tightened securely. Health
- Shock and vibration encountered during shipping
caused erroneous output from two vaporizers [manufacturer letter]. 1984
- A selector mechanism fitting failed to connect properly to a vaporizer.
Anesthesia Unit Vaporizers [10-144]
Cause of Device-Related Incident
Device factor: Improper maintenance, testing,
repair, or lack or failure of incoming inspection
User error: Failure to perform pre-use
Support system failure: Lack or failure of
incoming or pre-use inspections
Mechanism of Injury or Death