To the Editor

No current consensus exists regarding when to replace an aging anesthesia machine. Each institution must examine the anesthesia machines presently in use and then decide in what direction to go. A number of factors should be considered in the purchase of new anesthesia machines to replace old ones:

1. Do the present anesthesia machines meet ASTM standards?

2. Do all the operating rooms have the same kind of anesthesia machine?

Today’s machines are of such sophistication that it is wise to have the same manufacturer supply all the operating rooms. Anesthesia providers will invariably make mistakes by switching from an anesthesia machine made by one manufacturer to an anesthesia machine manufactured by a different manufacturer. If possible, it is prudent to have a similar model of anesthesia machine in all the operating rooms, including OB, Radiology, etc. Patients are still being harmed from machines in out-of-OR sites that are unfamiliar to anesthesia providers on a day-to-day basis.

3. Do the present anesthesia machines have a reasonable maintenance history?

4. Has the hospital contract for maintenance been satisfactory in the last three years? Service of the anesthesia machine is critical to good performance. Careful consideration must be paid to the local quality of service for the anesthesia machine. It is a disaster to purchase a top-of-the-line anesthesia machine and, with the slightest glitch, then have it standing idle while waiting for the distant technician’s arrival to (it is hoped) save the day.

5. Risk management principles will require the hospital to provide anesthesia machines meeting ASTM standards and complying with the monitoring standards practiced in and acceptable to the anesthesia community, e.g. the ASA standards. Will anesthetic gas monitoring become a standard? The monitoring of the levels of the anesthetic gas is certainly being used outside of teaching hospitals and most likely, measurement will one day become a standard. At least purchase a machine that can be upgraded to accept an appropriate gas monitor in the future.

Historically, anesthesia providers have used anesthesia machines for even up to 20 to 30 years. Today, the technology is changing so rapidly we must reexamine this policy. Perhaps if we purchase “modular” machines we can allow for updates in the future and extend the life of our expensive machines. I see no reason to get rid of anesthesia machines that meet ASTM standards, are capable of “modular” upgrades, and have satisfactory service records. I would seriously consider replacing anesthesia machines that have poor service records, are not easily upgraded, and are 8-12 (or more) years old.

William Clayton Petty, M.D. Professor and Chairman Department of Anesthesiology Madigan Army Medical Center Tacoma, WA