Concern over aging and possibly “obsolete” anesthesia equipment, particularly gas delivery machines, has been growing in the anesthesia community and has prompted discussion, study, and action. Parallels to the aviation industry’s questions about aging aircraft are clear.
The aviation metaphor has been aptly applied to describe the practice of modem anesthesiology. Induction and emergence are likened to takeoff and landing. On occasion during a long and uneventful anesthetic, a colleague may casually remark that the patient is on “autopilot” ‘An aviation aphorism holds that “There are old pilots, and there are bold pilots, but there are no old, bold pilots”.
So too in anesthesia is it hoped that time, experience and training will temper hasty judgement. The anesthesia worksite is often compared to an airplane cockpit. Anesthesiologists seek ergonomically designed workstations with “heads up” displays and intelligent and “harmonized” alarm system in the belief that improved instrumentation will aid clinicians through a “stormy” case.
The majority of accidents in both professions have been attributed to “pilot error”. Mechanical faults have been far less frequent, but recently safety issues have become associated with aged equipment. Within the last year, there have been three aviation accidents with serious injury or loss of fife wherein the age of the aircraft was implicated as a possible cause of structural failure One of these airplanes was 19 years old and had logged over 90,000 takeoff-and-landing cycles; this may have directly contributed to the structural failure. With proper maintenance, however, many aerospace engineers indicate an airplane can fly forever. They acknowledge that the costs of maintenance and safety enhancements will increase each year, but claim the age of an aircraft itself is irrelevant to a discussion of safety. They also caution against unbridled faith in leading edge technology and point to the recent crash of a sophisticated “fly-by-wire’ European commercial airliner.
Panel Held
In 1988, the ASA Committee on Equipment and Standards undertook the task of examining the issue of aging anesthesia gas machines. Initially a panel was held at the Annual Scientific Meeting in San Francisco to discuss the issue of anesthesia machine obsolescence. Dr. Stanley Weitzner, who has been active in writing national standards for anesthesia equipment for over ten years, spoke on the elements of a modem anesthesia machine. He emphasized that a new anesthesia machine standards (ASTM F 1161 -88) has superseded the familiar, but older 1979 ANSI Z79.8 standard; all machines purchased in 1989 should meet the newer standard.
Dr. Clayton Petty, author of a recent book on anesthesia machines defined the elements of an obsolete anesthesia machine. Dr. Jerry Dorsch, another well-known author on anesthesia equipment spoke to the delicate cost-benefit ratio in trying to update older equipment to reflect modern engineering safety advances. Finally, Mr. Joseph Radzius, an attorney with extensive regulatory and litigation experience defending equipment manufacturers Save a legal opinion on old anesthesia equipment. He counseled that the pejorative adjective “obsolete”‘ be dropped from the discussion; rather one should speak of the presence or absence of certain safety enhancements.
In the open discussion that followed, the panel and audience recognized that often other issues are intimately associated with equipment failures. These are improper or reduced maintenance, inadequate in service education, substandard equipment monitoring, failure to use checklists, and lack of familiarity with equipment standards. Eventually a technology matures and small gains in safety are achieved only with disproportionately greater expenditures. Anesthesiologists in an era of increasingly restricted funding have questioned whether it is better to first replace an older machine that meets the Z-79 standard or to upgrade patient monitoring to include oximetry, capnometry, and agent-spe6fic concentration monitors?
Following this panel and in response to a charge by the Board of Directors of the ASA, the Committee on Equipment and Standards met in January to write a “Policy for Assessing Obsolescence”. This March the ASA Board of Directors approved the following policy submitted by the Committee on Equipment and Standards:
Proposed Policy
The age of an anesthesia gas machine has not been demonstrated to be a factor in anesthetic mishaps. An anesthesia gas machine, however, which no longer functions as designed and is not modified to meet acceptable levels of performance and monitoring should not be used.
Each anesthesia department should establish a protocol to assure that all anesthesia staff members are qualified in the operation of each type of gas machine, ventilator and monitor before use.
Anesthesia and health care in general now face a problem that confronted commercial aviation earlier in the decade; the pressures of economic deregulation and restricted funding have come into conflict with the increasing public and regulatory expectations of improved safety performance Interestingly, neither the States of New Jersey or New York, which have implemented stringent regulation with regard to the practice of anesthesiology have addressed the issue of equipment safety. Rather, these regulations speak to specific safety measures which must be in place, regardless of machine age These safety measures include diameter index safety system, pin index sat* system, fail-safe system, and a vaporizer interlock system.
Dr. Lees, Professor and Chairman at New York Medical College, is a member of the Editorial Board of the APSF newsletter and Chairman of the ASA Committee on Equipment and Standards.