US1823767A - Apparatus for administering anesthetic and nutrient gas under pressure - Google Patents

Description

Se t. 15, 1931. v H. w. c. SCHROEDER 2 APPARATUS FOR ADMINISTERING"ANES THETIC AND NUTRIENTJGAS UNDER PRESSURE Filed March 22, 1928 Patented Sept. 15, 1931 UNITED STATES PATENT OFFICE HANS WILHELMI CHRIS'I'TAN SCHROED'ER, F LUBEGK, GERMANY, ASSIGNOR TO DBAGERWERK, OF LUBECK, GERMANY APPARATUS FOR ADMTNISTERING ANESTHETIO AND NUTRIEN '1 GAS UNDER PRESSURE Application filed March 22, 1928, Serial No.*263,799, and in Germany May 24, 192i.

Operations on the cavity of the chest, as is well known, dare only be carried out, if the lungs from the mouth and the nose are subjected to a pressure equal to that exerted by a column of water of 5 to centimeters above atmospheric pressure, and thus are continuously inflated. It is of particular importance that the pressure is not subjected to noxious fluctuation while '10 the patient is inhaling and exhaling. The

excursions of the lungs if possible should not exceed those caused by the depth of the breathing. In the devices for ressure inhaling narcosis known hereto ore, either the fluctuations of pressure are very heavy, so that the similar heavy movements of the lungs greatly hinder the working in the field of operation, the thorax being open, or it becomes necessary to allow large amounts of narcotic gas (50 to 70 liters per minute) to enter and escape, of which that required to fill the lungs is such a small percentage that it does not materially influence the pressure. Moreover movable compensating vessels loaded with weights or compressed with gas have been used for receiving and giving out gases, for instance having the shape of bags or bellows. The drawback of such vessels resides in thisthat they are 39 too idle in commencing to operate. The bellows material and the load cannot follow quick enough, so that on a frequency of 15 to 20 respirations in the minute consid erable fluctuations of pressure say 50% and more occur.

By the apparatus constructed according to the resent invention the said drawbacks are re uced to a minimum. This is secured by connecting the breathing circuit of the 40 device with the inside of a bell adjustably held in position within a liquid containing tank. This bell is provided with a series of gas outlet openings, preferably distributed about the complete circumference of thebell at equal depths below the level of the liquid. The bell 'may be adjustable as to height and provided with any kind of device for reading off the difference in level between the surface inside and that outside the bell. The fluctuations of pressure with the new apparatus are so slight that they do not trouble the operator, and the consumption of gas may be reduced almost to the physiologically necessary amount. The reduction of the gas consumption has the double advantage, on the one hand that the costs of the expensive gaseous anesthetics, for instance azotic protoxide or protoxide of nitrogen (laughing gas) are cut down to a minimum, and on the other hand that scarcely any anesthetic vapours are exhaled into the operating-room. The lading of the air in the operating-room with narcotic vapours is very injurious to the attendants particularly when frequently repeated, an 5 this must be considered a great drawback of the pressure, narcosis a paratus requirin a large consum tion 0 gas. 1

t may be remar ed that gasometersf as a reservoir for anesthestics have been used heretofore by dentists in their practice.

In the drawing, an apparatus constructed according to this invention is provided with apressure regulator adapted to be used in connection with anesthesia devices with circulating breathing, though the invention is not restricted to such devices. The circulatory breathing, that is the re-inhaling of the unconsumed gases after exhaling and purifying from carbonic acid and water requires as is known a minimum amount of gas, namely scarcely two liters in the minute.

The vessel 1 contains the anesthetic gas and the vessel 2 oxygen. The flow of both gases is'regulated by the valves 3 and 4 respectively. The gases flow by, way of the pipes 5, 6 and 7 into the passage 8, and from there into the breathing bag 9 or to the mask 11 by way of the pipe or hose 10, respectively. The exhaled gas passes through the flexible pipe 12 into the carbonic acid and water absorption cartridge 13 and hence through the pipe 14 back into the breathing bag 9. The non-return-valves 15 (inhaling valve) and 16 (exhalingvalve) compel the gases to follow the breathing circuit in the manner described. The vent cock 17 serves for' allowing any surplus of gas to escape from "the circulation outwardly by degrees or quickly.

The pressure regulating device, by means of which the gas in the complete circulating system from the mask to the gas feed pipes 5 and 6 is held above atmospheric pressure and by which this pressure can be regulated and held substantially constant, comprises a vessel or tank 18 containing water or other liquid and a bell 19 firmly held therein, communicating by a flexible pipe 20 with the passage 8. By. way of the pipe 20 the narcotic gas passes into the bell provided with a plurality of perforations 21. When there is no possibility of the gases continuously paid out by the vessels l and 2 escaping outwardly from the edges of the mask 11 which fits closely and snugly on the face of the patient, and when the cook 17 is fully or nearly closed, the water within the bell 19 will be displaced until gas freely escapes by way of the perforations 21 through the water in the tank 18. The pressure of the gas within the bell, which is also the pressure of the gas within the breathing circuit, is equal to the depth of immersion of the bell below the original level of the liquid in the tank plus the rise of that level due to the expulsion of water from within the bell by the pressure of the entering gas, in centimeters of water. If by way of example the horizontal cross section of the bell and of the annular space between the bell and the tank 18 are equal, there will be a difference between the inner and outer level of 10 centimeters at a depth of immersion of 5 centimeters. The pressure above atmospheric pressure within the breathing circuit and in the lungs of the patient will then be 10 centimeters.

The bell 19 within the tank 18 is adjustable as to height. With this object in view the bell has a shaft or rod 23 clamped to a holder or bracket 22 by a set screw 24, which, when loosened, allows of the rod being slid up or down to adjust the bell to the desired height, whereupon the screw 24 may be screwed ,up to again firmly hold the bell in adjusted position. Besides means may be provided such as a scale or the like, which allows of the levels within the tank 18 and within the bell 19 or the difference of the same to be read off. The adjustability of the bell together with the means for allowing the levels to be read off constitute a good and simple pressure adjustin means.

It is of advantage to m e the tank 18 as large as the conditions of the operating room allow. The cross-section \of the bell 19 must be of the minimum area, such of 1000 square centimeters for example, which has given good results. The amount of air inhaled and exhaled at a medial depth is about 500 com. and since the breathing bag 9 is generally fully inflated and only consequently to a certain elasticity is able to give up and take up a small amount of gas alternatively withdrawn and given back, the movement of the main amount of gas takes place within the pressure bell 19. Owing to its large area the light liquid water flows quickly in and out. The level of the water is advantageously subjected only to fluctuations of about 0.5 to 1 cm., since the fluctuations of pressure do not surpass this height. It has been proved that these fluctuationsof 0.5 to 1 cm. do not disturb the operations in the cavity of the chest nor those on the lungs.

Any amount of gas closed over and above the physiologically necessar amount escapes on every or on every secon or third exhaling by the small perforations 21 in a number of small bubbles, thus without causing vibratory shocks of pressure. lVhen the patient is inhaling, the water rising within the bell shuts off the lateral perforations.

The novel pressure regulator if desired may be connected with the pipe 14 or with the pipe above the cartridge instead of being connected with the passage 8 as shown. It may be used in connection with narcosis a paratus for liquid or fluid (vaporous or nebulous) narcotics or with combined ap aratus for gaseous and liquid narcotics, an also with narcosis apparatus without circulation.

I claim 1. An apparatus adapted for use in administering anesthetics in substantially gaseous state under pressure, comprislng a breathing circuit, a supply of gas under pressure communicating with said breathing circuit, a bell of relatively large size connected with the breathing circuit, a liquid containing receptacle, and means for supporting saidbell Within the liquid containing receptacle in fixed relation with respect to said receptacle.

2. An apparatus as set forth in claim 1 in which the bell is provided with a plurality of perforations spaced equally from the lower edge of the bell, said perforations being below the level of the liquid within the receptacle.

3. An apparatus as set forth in claim 1 in which the supporting means is adjustable.

4. An apparatus as set forth in claim 1 in which the area of a horizontal cross section of the bell is substantially equal to that of the annular space between the bell and the walls of the liquid containing receptacle.

5. An apparatus as set forth in claim 1 I in the breathing circuit.

In testimony whereof I have signed my name to this specification.

HANS WILHELM CHRlSTlA SCHROEDER.

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