GB1008520A - A machine for the administration of anaesthetic gases or for the ventilation of an apnoeic patient - Google Patents

Abstract

1,008,520. Respiratory appliances. CAPE ENGINEERING CO Ltd and BYFIELD INVESTMENTS Ltd. Oct. 12, 1962 [Oct. 14, 1961], No. 36947/61. Heading A5T. A respiratory apparatus, which may be used for administering of anaesthetic or for forced breathing, has means for changing from automatic to manual operation or vice versa at will. The changeover is primarily effected by a selector valve assembly comprising three gauged valves 14, 13, 66 and, in the position shown oxygen or. other gas, received through flowmeters 2 or from an emergency supply 65, is fed into a duct 6 and any excess is accommodated in a bag 3. A positive pressure bellows, actuated by a shaft 81, forces it in the direction of the arrows 8 part a mechanically controlled valve 12 and connection 15 to the patient and subsequently, also actuated by the shaft 31, a valve 18 is opened and a second bellows 21 withdraws the gas from the patients lungs, through a carbon dioxide absorber 23 for recirculation, any excess in this case being accommodated in a bag 25. The timing of the breathing cycle is adjusted by a variable ratio gear-box 32 connected to the driving motor 30 and the volume passed at each cycle is adjusted by changing the position of the fulcrum of the lever 40 which extends between the bellows 9 and its actuating crank 37. When the selector valve assembly 66, 13, 14 is rotated anti-clockwise through 90 degrees a switch, not shown, stops the motor 30 and gas from inlet pipe 1 passes directly, through pipe 68, to the part of the circuit to the right of the valves 13, 14, which is now isolated from the rest of the equipment. In addition, a rebreathing bag 60 is connected through non-return valves to this effective part of the circuit so that by manually squeezing and releasing the bag 60 an operator can force gas into the patient's lungs, in the direction of the arrow 8, and withdraw it, through the carbon dioxide absorber 23, as indicated by the arrow 17. Spring loaded relief valves 28, 74, 75 are provided to prevent the building up of excessive pressures and a valve 20 limits the degree of suction which can be applied to the patient.