To the Editor:--Reading the potentially disastrous case of an intraabdominal fire by Greilich et al. [1]prompted me to immediately call a major medical gas supplier here in Australia to check whether such a dangerous gas cylinder was available. As in the United States, routinely available Carbogen (5% CO2in 95% Oxygen2) has a different pin index to 100% CO2. Other mixtures of CO2and Oxygen2can be supplied on request, but would normally be fitted with a bull-nosed industrial-type valve, unless a medical-type pin-indexed valve was requested. Also as in the United States, if such a medical valve was requested, mixtures with 7% CO2or greater would be fitted with pin positions identical those of a 100% CO2cylinder. However, the guidelines also specify that the color of the body of the cylinder should be that of the predominant gas (i.e., > 50% concentration), and the shoulder of the cylinder should be colored that of the “minor” gas. With these guidelines, 14% CO2in 86% oxygen would look more like an oxygen cylinder but would only fit a CO2pin-indexed yoke. Although still potentially dangerous, this almost certainly would have been safer than the safety features described in the report (i.e., a small green collar plus a label). One also wonders why such a mixture with a medical pin index existed in the hospital in the first place.
Mark Priestley, M.B.B.S., F.A.N.Z.C.A.; Staff Specialist, Department of Anaesthesia, Westmead Hospital, Hawkesbury Road, Westmead 2145 NSW, Sydney, Australia.
(Accepted for publication May 14, 1996.)
