GB1031049A - Lung ventilating equipment - Google Patents

Abstract

1,031,049. Artificial respiration apparatus. AIR-SHIELDS Inc. May 30,1963 [Feb. 5, 1963], No. 21678/63. Heading A5T. Artificial respiration apparatus comprises a collapsible reservoir 20 for connection with the lungs, the reservoir being alternately collapsed and expanded by the supply of compressed gas to a chamber 32 surrounding the reservoir and a control device 38 which establishes the cycle of operation of the compressed gas and includes a valve 138 (Fig. 9 not shown) for separately and independently adjusting the expiratory phase of the equipment. Air or oxygen and if desired an anaesthetic gas is supplied to the patient through a supply and absorber unit 25 connected by inhalation and exhalation tubes 27, 28 to a mask or tracheal tube. A breathing bag 20 connected in the patient circuit is alternately collapsed and expanded to induce inspiration and expiration by the supply of gas to and withdrawal of gas from a transparent chamber 32 surrounding the bag 20. The chamber 32 receives gas from a source 42 through a valve 40, the controlling chamber of a normally closed dump valve 39b, a controller 38, ducts 37, 38 and a valve 35. When the controller causes the gas supply to the chamber to cease to permit expansion of the bag in the expiratory phase, gas under pressure is supplied through the controller to a chamber 49 to cause opening of a dump valve 48 so that gas in the chamber is vented to atmosphere via the valve 35, valve 48, an outlet duct 53 and a flap valve 54. During the expiratory phase a negative pressure may be developed in the chamber 32 by the passage of operating gas from a nozzle 61 through a venturi 62 which communicates with the outlet duct 53. Relief valves 69, 70 are associated with the outlet duct and the operating gas supply, respectively. A diaphragm valve 56 between the breathing bag and the operating gas supply has a control chamber communicating with the chamber surrounding the bag so that when the pressure in the bag exceeds that in the chamber during expiration, breathing gas is vented into the operating gas circuit and thence to atmosphere through the dump valve 48 and the flap valve 54. In the event that the operating gas supply fails so that the dump valve 48 remains closed, the dump valve 39b opens so that the bag can be vented to atmosphere. A tube 29 connecting the patients breathing mask or tube to the breathing circuit is connected via a control device 67 and ducts 66a, 66 to the controller 38 so that in the event that pressure in the tube 29 is reduced due to an inspiratory effort by the patient the controller is switched over to inspiratory operation. The apparatus may attenuatively be operated manually by a bag 71 to which air or other gases may be supplied, the breathing bag being vented during expiration through the valve 56 and an axial passage 72 in the valve 35 which is set to cut out the automatic operating circuit.