title: Closed-circuit halothane and enflurane using an in-circle Goldman vaporizer.
abstract: A closed-circle absorber system incorporating an in-circle Goldman vaporizer was used to administer halothane or enflurane in oxygen to adult patients. The attained inspired and end-tidal concentrations of volatile agent after a period of stabilization at each vaporizer setting were measured by mass spectrometry. During spontaneous respiration under halothane the ranges of inspired concentrations at settings 1, 11/2 and 2 were respectively 0.5-0.9%, 1.4-2.4% and 3.3-4.5%. corresponding inspired enflurane concentrations at the same settings were 0.8-1.4%, 1.9-2.8% and 3.7-5.0%. IPPV to 5% end-tidal carbon dioxide, although increasing the inspired concentrations slightly, produced considerable increases in end-tidal concentrations. Minimal pre-oxygenation was used to assess the problem of nitrogen accumulation within the circuit. The maximum nitrogen concentration was 56%.
mesh_terms: D000328:Adult; D000368:Aged; D000769:Anesthesia, Inhalation / Q000295:instrumentation*; D004737:Enflurane / Q000008:administration & dosage* / Q000032:analysis; D006221:Halothane / Q000008:administration & dosage* / Q000032:analysis; D006801:Humans; D007385:Intermittent Positive-Pressure Ventilation; D008875:Middle Aged; D012119:Respiration; D013990:Tidal Volume
chemical_list: D004737:Enflurane; D006221:Halothane