Patent GB-426171-A (GB)
Title: Improvements in apparatus for giving anaesthetics
IPC: A61M16/10
Filed: 1934-06-29
Abstract: 426,171. Anµsthetic apparatus. CARRE, J., 52, Longue Rue, Leers, Nord, France. June 29, 1934, Nos. 19316, 19317, and 19318. Convention dates, July 18, 1933, Aug. 18, 1933, and Nov. 2, 1933. [Class 81 (ii)] Apparatus for administering anµsthetics is characterized by a closed path for the respired gas including oxygen regenerating means, a cock openable to atmosphere permitting expulsion of air before use, a source of anaesthetic under pressure, and a cock to cut off the mask when desired. As shown in Fig. 1, a mask 1, having a pneumatic sealing ring 21 and integral head straps 23, is connected to the respiratory circuit through a cock 19, which cuts off the mask and opens it to atmosphere in emergency. The breathing circuit comprises a pipe 2, containing a non-return valve 3, and leading to a cock-controlled gas-bag 4, in a branch circuit, and to an oxygen-regenerating canister 9. The canister is connected, through a non-return valve 12, to a cock 14 openable to atmosphere, and thence through a valve 13 to a return pipe 2<1>, into which open gas-bottles 15, 16, containing nitrous oxide, ethyl chloride or other anµsthetic, and a cock-controlled gas-bag 17. A shunt circuit 61 has connected to it a container 10 for an alternative supply of oxygen evolved by dropping water through a valve 11 on to oxygen-generating material. Alternative flow of gas wholly or partly through the canister 9 or the pipe 6<1> is controlled by interconnected cocks 7, 8. In use, air rich in carbon dioxide, for emergency use, is first collected in bag 17 by respiration with cock 19 open to the circuit and cock 14 closed, canister 9 being cut off and oxygen being supplied from container 10. Cock 19 is then closed, cock 14 opened to atmosphere, and the whole circuit, including bag 4, filled with anaesthetic gas from the gas-bottle 15. Cocks 14, 19, are then turned to close the circuit and connect it to the mask for administration of the anaesthetic, whereafter closed-circuit breathing of anµsthetic, with oxygen regeneration, takes place. As assembled for use the pipes 2, 6<1>, 2<1> form a rectangle resting on a table and supporting the containers 9, 10 beneath it, the gas bags and bottles being suspended from the pipes. A modified layout is described in which the canister 9 is held in a cradle hooked or screwed to the edge of the operating table and supporting the pipes of the circuit; the junction of the pipes 2, 2<1> contains a cock opening to either pipe, but not both simultaneously, and byepassed by a pipe containing the valve 3 ; a pipe leads from the cock across the apparatus to the mask over the table and is connected by side pipes to an anµsthetic gas bottle and a bottle containing a mixture of carbon dioxide and oxygen, which replaces the bag 17 and the container 10. The mask 1 may be replaced by a full face mask having a re-entrant pocket into which the fingers may be inserted to test the optical reflexes. The canister 9 comprises an open-ended, elongated, rectangular box having two adjacent sides detachable ; the box is filled with gauze cylinders containing oxylith arranged in successive layers at right angles to one another, closed by gauze at the ends, and inserted into an outer box the detachable ends of which support pipes containing asbestos fibre filters and have beneath them asbestos filter layers. In the modification shown in Fig. 9 for short anµsthia a mask 92, having rings 94 for attachment to the face, communicates with a valve chamber 96 opening to atmosphere at 97 and containing a valve 99. Above the valve is a pipe 102, supporting an anaesthetic gas bottle 103, an oxylith container 101 having a central perforated diaphragm, and a gas-bag 104. In use, gas from the bottle 103 is allowed to fill the bag, the mask is then applied and valve 99 turned counterclockwise to close the aperture 97, this movement momentarily cutting off the mask and permitting the expulsion of air in chamber 96 through the aperture 97 by the anaesthetic gas. Breathing then takes place into and out of the bag 104 through the oxygen regenerator 101. Several gas-bottles, containing for example anµsthetic, carbon dioxide, and oxygen respectively, may be connected in parallel to the pipe 102 for alternative use.