Improvements in Apparatus for Administering Anaesthetics

13,890. Hatch, S. R. Aug. 2. Medicines, administering; inhalers.-Relates to apparatus by which nitrous oxide may be administered direct from a gas cylinder, either alone or together with ether and oxygen, means being provided for expiration either into a gas bag or into the open air. The apparatus comprises a gas bag 7, valves 12 and 13, a mask 5 having a perforated disc on to which ether can be dropped through an opening 31 having a screwed cap as shown, and tubes 8 and 9 connecting the valves 12 and 13 to the supplies of oxygen and nitrous oxide respectively. The valve 12, as shown separately in Fig. 2, consists of a cylinder which can be turned in the case 1 so as to bring any one of a series of openings 16 of differing sizes, formed in it, opposite the oxygen supply tube 8. The valve 13 consists of a cylinder mounted in the case 1 and formed with openings 23, 26, 28, 29 adapted to register with an opening 27 in the case, and with the tube 9. Non-return valves 21 and 24, opening inwardly and outwardly respectively, are fitted over the openings 23 and 26. The connection of the bag 7 is controlled by apertures 18 formed in the end of the cylinder 13 and adapted in certain positions to register with openings 20 in a disc which closes the entrance to the gas bag. In the position shown in Fig. 4, the patient breathes external air with or without oxygen or ether. By rotating the opening 26 to the opening 27, the patient inhales nitrous oxide from the tube 9, and exhales through the opening 27. A further rotation opens the valve 18, and brings the opening 29 over the tube 9 ; in this position, the gas bag and mask are both open to the tube 9. Further rotation closes the tube 9, and allows the patient to inhale from and exhale into the bag 7.