Technical Topics

David E. Lees, M.D.

Is Your Central Gas Supply Tamper-Proof?

The mere presence of a skilled and certified anesthesia practitioner at the head of the operating table surrounded by the most advanced space-age monitoring can not by itself guarantee patient safety. The “technoglitz” of modern monitoring notwithstanding, patient safety, much like good detective work requires more perspiration than inspiration; it is a function of vigilance, planning, and training. Unfortunately, all too often, the operating room may be at the mercy of events that occur elsewhere in the hospital.

Recently, an employee of a hospital was interrogated by the police and later suspended after allegedly twice tampering with valves that regulated the pressure and quantity of nitrous oxide provided to an operating suite by a bank of cylinders. No patients were injured by the pipeline pressure fluctuations and at the time of the tampering, the pressure alarms promptly alerted the staff.

In a similar case, the main oxygen shut-off valve located in the hospital laundry room, was accidentally closed by an employee who thought that it controlled the central heating! A nearby sign identifying it as the main oxygen shut-off valve apparently went unheeded. Low pressure alarms functioned properly and alerted hospital personnel. The employee, sensing something was wrong, fled the scene. While there were no reports of problems in the operating rooms, several newborn infants were deprived of oxygen for several minutes, according to official reports of the event.

These two “near misses” demonstrate that patient safety requires more than just bedside skills. The recent shift in emphasis from environmental safety affecting all patients to issues of individual patient safety in a one-on-one setting should not lessen the importance of the former; rather it acknowledges that all anesthesia personnel now are expected to be familiar with the standards enforced by local jurisdictions and national accrediting bodies, such as the I.C.A.H.

It may be timely, however, to see if you can answer the following questions about your institution: 1) Is access to the shut-off valves properly controlled and locked?, 2) Are the supply systems in dedicated rooms or structures and not shared with the laundry?, 3) Can you locate the “emergency low pressure gaseous oxygen inlet” in the central patient gas supply? 4) Do you know where the two master alarm signal panels are as well as the area alarms for all anesthetizing locations? How recently were they tested?

For guidance in this area, anesthesia personnel have traditionally looked to the National fire Protection Association which in the past has issued pamphlets on the safe use of inhalation anesthetics (56A), non flammable medical gas systems (56F), emergency power (76A) and the safe use of electricity in patient care areas (76B) to mention but a few of their publications of importance to anesthesia. Recently, however, the N.F.P.A. has combined them into one authoritative manual entitled “NFPA 99-Health Care Facilities, 1987 Edition”. This document (NFPA U8-99-87) should be in the library of all anesthesiologists and anesthetists; it may be obtained from the N.EP.A., Batterymarch Park, Quincy, MA 02269-9904 for S 17.50 plus a $2.85 handling charge. Monitoring may detect a problem, but knowledge can prevent one!

Topic Prepared by David E. Lees, M.D., Professor and Chairman, Department of Anesthesia, New York Medical College and a member of the APSF Newsletter Editorial Board.