title: Totally closed circuit nitrous oxide/oxygen anaesthesia.
abstract: Totally closed circuit anaesthesia has been used with nitrous oxide/oxygen gas mixtures, supplemented by halothane for spontaneous breathing, or by opiates for artificial ventilation. Oxygen expenditure averaged 227 ml/min, while nitrous oxide expenditure declined exponentially from an initial value of 462 ml/min to 110 ml/min after 2 hr. These flow rated included gas sampled for analysis. Inspired oxygen concentration was maintained at 30 per cent by monitoring with a paramagnetic analyser. Halothane expenditure average 3.5 ml (liquid) per hr. Halothane concentrations in the operating theatre atmosphere did not increase above 0.03 p.p.m.
mesh_terms: D000368:Aged; D000388:Air / Q000032:analysis; D000397:Air Pollution / Q000517:prevention & control; D000769:Anesthesia, Inhalation / Q000295:instrumentation / Q000379:methods*; D003365:Costs and Cost Analysis; D004469:Economics, Hospital; D004578:Electron Spin Resonance Spectroscopy; D005260:Female; D006221:Halothane / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009584:Nitrogen / Q000032:analysis; D009609:Nitrous Oxide / Q000009:adverse effects / Q000032:analysis; D009873:Operating Rooms; D009892:Opium; D010100:Oxygen / Q000032:analysis; D012212:Rheology; D013056:Spectrophotometry, Ultraviolet; D014978:Xenon
chemical_list: D014978:Xenon; D009892:Opium; D009609:Nitrous Oxide; D009584:Nitrogen; D010100:Oxygen; D006221:Halothane