Volume 2, No. 1 • Spring 1987

Anesthesia Machine Standards Enhance Safety

Kay Plantes, Ph.D.; Anne Berssenbrugge, Ph.D.

Part one of this article described ten technological advancements in anesthesia machine design which have significantly improved patient safety Yet, many of the machines currently in use do not contain these safety features which have been developed primarily within the past ten years.

Of necessity, capital spending limitations have led to a situation in which the equipment inventories of many hospitals are comprised of anesthesia machines which vary vastly in age; some are new, some may be more than twenty years old. Thus, an important ingredient in managing anesthesia safety is for clinicians to understand the capabilities, limitations and operation of each anesthesia machine they use.

Knowing when to replace older units and how to assess the adequacy of safety features available on currently marketed units also plays a role in managing anesthesia safety. To this end, it is valuable to understand the design and manufacturing standards that apply to anesthesia machines and the extent of their role in promoting equipment safety. This article addresses two of the most common questions asked of anesthesia systems manufacturers about standards: “Do our hospital’s anesthesia machines meet standards?” and “Do the machines you sell meet standards?”

While the intent of each question is straightforward-users wish to ensure that equipment complies with safety criteria established by external authorities-the answer is considerably more involved.

The anesthesia community is, in fact, affected by a variety of “standards”. These include standards of patient care defined by institutions, professional societies, and insurance companies; standards for hospital and departmental certification (ICAH); implied standards of care used in the courts to decide the outcome of medico4egal cases; and rules which govern the design, performance and manufacture of medical products.

Manufacturing procedures of anesthesia equipment manufacturers are governed by legally mandated regulations that a company must follow under the threat of being brought to court or shut down. In addition, product design standards for safety and performance exist, but they are not now part of the regulatory structure. However, they may be either mandatory or voluntary.

The major regulations which govern anesthesia equipment manufacturers are those defined by the U.S. Food and Drug Administration (FDA). It was not until 1976 that the FDA further defined and extended its authority in regulating medical devices, with the passage of the Medical Device Amendments to the Food, Drug and Cosmetic Act, and its promulgations through administrative rules.

The primary FDA laws and resulting regulations which govern the activities of anesthesia equipment manufacturers include:

1. Medical Device Amendments, 1976: Regulates product labeling, manufacturer registration and new product introduction procedures.

2. Good Manufacturing Practices, 1978: Regulates medical device manufacturing, distribution and quality assurance procedures, including procedures a manufacturer must follow for product recall.

3. Mandatory Device Reporting, 1984: Governs how and when manufacturers report alleged serious malfunctions of their equipment and injuries and deaths occurring while their medical device was in use.

While the FDA has the authority under the 1976 Medical Device Amendments to regulate the performance and safety characteristics of anesthesia capital equipment (i.e., specific features which a medical device must contain), it has not, to date, exercised this authority. For example, the FDA does not require an anesthesia machine to be designed to preclude delivery of hypoxic mixtures to the fresh gas outlet. Recently, however, the FDA published notification in the Federal Register of its intent to issue regulations on standards of performance for some medical devices. In deciding which specific medical devices deserve its limited resources for producing regulatory standards, the FDA evaluates whether appropriate voluntary standards exist for a given medical device. Anesthesia machines and monitors have not been listed among the products to be initially addressed.

While the design of anesthesia equipment is not currently regulated by the federal government, it is measured against a broad array of voluntary standards. These standards are written by various technical, industrial, national, and international organizations composed of professional experts from the medical and manufacturing communities. The standards are based on a consensus of opinion and/or the result of extensive testing. Some state, county, and city governments reference standards as mandatory for the equipment purchased by hospitals within their jurisdiction. Thus, the standard functions like a law for any manufacturer wishing to sell equipment in these locations.

The major voluntary standards that affect the design of anesthesia capital equipment manufactured in the U.S. include:

1. International Organization for Standardization ISO 5358-198a International standards for continuous flow inhalational anesthetic apparatus.

2. American National Standards Institute Z79.81 979U.S. standards of minimum performance and safety for continuous-flow anesthesia machines for human use

3. Underwriters Laboratory, Inc. 544 1976: U.S. Standard for saw: medical and dental equipment. 4. Compressed Gas Association, Inc. VI 1 9 77. U. S. standards for compressed gas cylinder valve outlet and inlet connections.

Many of these standards are undergoing major revision. The ANSI standard for anesthesia machines, for example, is currently being rewritten by a subcommittee of the American Society for Testing and Materials (ASTM). As clinicians, manufacturers, insurance officials and hospital administrators work to improve anesthesia safety through the activities of the Patient Safety Foundation, it is interesting to reflect on the importance of regulations and standards. Are they a good vehicle for ensuring that anesthesia equipment meets a desired minimum safety level?

If an anesthesia system is designed and manufactured to conform with both regulations and standards, it should provide the user with the minimum level of safety and performance dictated by those criteria. However, because standards are voluntary, the user should not assume that all manufacturers’ equipment complies. Furthermore, it is important to note that standards can be slow to change and may not keep pace with the development of new technology. Equipment that does meet design standards may not offer the most up to date safety features available.

Standards and regulations that relate to industry are one part of enhancing anesthesia safety, but by themselves they will not ensure that the current level of anesthesia patient safety is maintained or improved upon. The current drive within the anesthesia community to both establish other standards, specifically those related to patient care such as the minimum monitoring requirements at Harvard, and to increase the extent and quality of ongoing clinical education offer a greater opportunity to continue to improve anesthesia safety. As these efforts continue, the role of anesthesia equipment manufacturers will be to participate in and support clinical education and to continue to develop and incorporate new safety features into the design of the anesthesia system. Anesthesia systems now and in the future are and will be designed to minimize equipment-related mishaps and to effectively manage monitoring information in a manner which promotes added vigilance over both the machine and the patient.

Kay Plantes, Ph.D. is North American Marketing Manager and Anne Berssenbrugge, Ph.D. is Product Manager, Anesthesia Systems, Ohmeda, Madison, M.