PubMed · 91829
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H Herxheimer. 1979-11-17. Fatal asthma.. https://doi.org/10.1016/s0140-6736(79)92492-9
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Several potential replacements for chlorofluorocarbons (CFCs) in metered-dose inhalers (MDIs) are flammable. The flammability hazard associated with their use was assessed using a range of MDIs containing 0-100% (w/w) n-butane (flammable) in HFC-134a (non-flammable) fitted with either 25-, 63-, or 100-microliters metering valves or continuous valves. In flame projection tests each MDI was fired horizontally into a flame, and the ignited flume length emitted from the MDI was measured. Flame projections of greater than or equal to 60 cm were produced by all formulations fitted with continuous valves which contained greater than or equal to 40% (w/w) n-butane in HFC-134a. Using metering valves the maximum flame projection obtained was 30 cm. This was observed with a formulation containing 90% (w/w) n-butane in HFC-134a and a 100-microliters valve. For a particular formulation, smaller metering valves produced shorter flame projections. Because many MDIs are used in conjunction with extension devices, the likelihood of accidental propellant vapor ignition was determined in Nebuhaler and Inspirease reservoirs and a Breathancer spacer. Ignition was predictable based on propellant composition, metered volume, number of actuations, and spacer capacity. Calculated n-butane concentrations in excess of the lower flammability limit [LFL; 1.9% (v/v)] but below the upper flammability limit [UFL; 8.5% (v/v)] were usually predictive of flammability following ignition by a glowing nichrome wire mounted inside the extension device. No ignition was predicted or observed following one or two 25-microliters actuations of 100% n-butane into large volume Nebuhaler (750 ml) or Inspirease (660 ml) devices.(ABSTRACT TRUNCATED AT 250 WORDS)
Volatile substance abuse has been reported in the literature over the past 20 years or so, and has apparently increased as countries have become more industrialised. This review attempts to clarify trends in volatile substance abuse, problems associated with this behaviour and possible solutions. Data sources included a Medline Search on volatile substance abuse over the last five years, Commonwealth publications, recent State and Territory inhouse publications, three research monographs from the National Institute on Drug Abuse (NIDA) and an article library from the author's workplace. Some 250 articles and monographs were identified, reviewed and categorised into sections relating to epidemiology (including mortality), physiological effects and responses to the problem. Articles were used for reference where they reflected the most up-to-date information or where they were seen as authoritative statements. While the body of knowledge concerning volatile substance abuse has improved, little progress has been made in finding effective solutions to the problem. The fact that users are typically young and that there is a real risk of sudden death associated with even initial use suggests that continuing research is needed to develop innovative approaches to the problem.
Metered dose inhalers containing halogenated propellants may interfere with mass spectrometer quantitation of halogenated inhalation anesthetics. We identify the propellant(s) in a commercially available metered dose inhaler that caused erroneous mass spectrometer readings. In addition, we identify the causes of different types of interference in different mass spectrometers.