title: Effects of fluorocarbon propellants on respiratory flow and ECG.
abstract: Ten subjects were exposed to the propellants freon 11, freon 12, freon 114, to two mixtures of freon 11 and 12 and to a mixture of freon 12 and 114. The length of exposure was 15, 45 or 60 seconds. Maximum expiratory flow-volume (MEF) curves and ECG were recorded before, and intermittently up to 1 hour after, exposure. Breathing level concentrations of propellants during exposure were determined by gas chromatography. All freons induced biphasic reduction of ventilatory capacity on inhalation. The first fall occurred within a few minutes of exposure while the second was delayed 13-30 minutes after exposure. The effects of mixtures were greater than those of individual freons. The relative fall in MEF 75% was more pronounced than that in MEF 50%. No clear-cut pathological changes in ECG were found. Nevertheless, most subjects developed variations in heart rate exceeding those noted before exposure. In a few cases inversion of the T wave, and in one case atrioventricular block, were observed.
mesh_terms: D000328:Adult; D000335:Aerosol Propellants / Q000494:pharmacology*; D000336:Aerosols / Q000494:pharmacology*; D005617:Chlorofluorocarbons, Methane / Q000494:pharmacology*; D004562:Electrocardiography; D006321:Heart / Q000187:drug effects*; D006327:Heart Block / Q000139:chemically induced; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008449:Maximal Expiratory Flow-Volume Curves; D012123:Pulmonary Ventilation / Q000187:drug effects*; D013268:Stimulation, Chemical
chemical_list: D000335:Aerosol Propellants; D000336:Aerosols; D005617:Chlorofluorocarbons, Methane