US2273790A - Mechanical resuscitator for combating asphyxia - Google Patents

Description

Feb. 17, 1942. H, H, RAYMQND` 2,273,790

MECHANICAL RESUSCITATOR-FOR COMBATING AS'HYXIA` Filed April 2e, 19:59 l

Patented Feb. 17, 1942 MECHANICAL RESUSCITATOR FOR COMBATING ASKPHYXIA Horace H. Raymond, Berlin, Conn., assigner to William H. Stephenson, New York, N. Y.

Application April 26, 1939, Serial No. 270,216

' (o1. 12s-ao) 13 Claims.

This invention relates to improved apparatus for providing mechanical resuscitation iny cases of asphyxie.

Asphyxiation occurs upon the failure of either cardiac or respiratory action. It has been found, that life continues in human `beings and the higher animals so long as the exchange of oxygen and carbon dioxide is continued in a normal way in the blood and tissues of the body. Ventilation of the body through the lungs serves to maintain oxygen and carbon dioxide in the tissues in proportion to their metabolic needs. Cardiac actionk through the-circulating blood accomplishes the supply of oxygen to, and the removal of carbon dioxide from, the tissues of the body. Circulation and respiration are thus interdependent and both are regulated by the gas pressure of oxygen and carbon dioxide in the tissues of the body, and respiration and circulation in turn serve during life to maintain the gas pressures in the tissues substantially constant in each part of the body. l

The reserve supply of oxygen in the human body is very limited, being sufficient to maintain life for only a few minutes when all supply from the outside is cut off. Many kinds of illnesses greatly increase the speed with which fatal as` phyxia may develop and it is thus most important in severe cases of asphyxia that prompt treatment be begun as speedily as possible to restore erator and/or patient, may be exposed to a grave risk of infection and of contracting disease.

Heretofore, complicated and expensive apparatus has been proposed for mechanical resuscita- Cil tion. It is an object of my invention to provide an improved, simple and dependable apparatus to produce artificial respiration by means of mechanically induced inhalations and exhalations; another object of my invention is to provide such a device in such compact form that it maybe kept available for emergency use without taking up more than a minimum amount of space; another object is to provide a device in which the positive and the somewhat lesser negative pressures created in the patients lungs are accurately controlled and limited; a further object of my invention is to provide a device having means for mixing air with 'the oxygen supplied to `the patient, and one which can be quickly conand maintain the proper pressure of oxygen in the patients body. While the patient is still breathing, manual resuscitation b-y exerting pressure rhythmically on the patients chest is possible. In more advanced stages when the patient has. become flaccid, the lungs are collapsed in the position of extreme expiration and the patients body lacks sucient elasticity for inhalations to be produced by the manual method. It is therefore necessary to expand and deflate the lungs in a positive manner. This may be done by the operator placing his mouth over the patients mouth and by means of his own breath rhythmically forcing air into the patients lungs and sucking it out. This mouth to mouth insuillation method has long been known and practiced but is subject to definite limitations. In the rst place, it is possible to exert toomuch pressure, thus doing damage to the alveoli, especially in the case of premature infants. In the second place, it is impossible to maintain such treatment for long, especially in cases with anaerobic suppuration of the lung because of the fetor; and in the third place, it has the disadvantage that the opverted from a resuscitator into an inhalator, or vice Versa.

The term oxygen is used herein broadly to include not only 100% oxygen but any gas or mixture of gases for insuilating a patients lungs or combating asphyxia. The invention will best be understood if the following description is read in connection with the accompanying drawing, in which Figure 1 is a front view of my apparatus largely in cross-section; e

Figure 2 is a front elevational view of my de- Vice;

Figure 3 is a detail sectional view of valve means for converting the device from a resuscitator to a simple inhalator, taken to the rear of the section of the valve shown in Figure 1;

Figure 4 is asectional view taken longitudinally along the line 4-4 through the valve means shown in Fig. 3.

Figure 5 is a detail view largely in cross-section indicating the iiow of gases in the apparatus during inhalation;

Figure 6 is a detail view largely in cross-section indicating the flow of gases in the apparatus during exhalation; and

Figure 7 is a detail sectional view taken at line 'I-`1 of Fig. 2 illustrating the crankl connection pin in the inactive position.l

The numeral I0 indicates the body portion of a device embodying my invention and has therein inhalation passageway II and exhalation passageway I2 which at its top communicates with the passageway I I intermediate its ends. Eachv of the passageways II and I2 is provided at'the` lower endwith screw threaded sockets I3 and I4 to receive the ends of conduits I3' and I4 for communication with a patients respiratory system, preferably through a mask M, (see Fig. 2) which is placed over the patients mouth and nose, and has a mouth piece, as will be well understood by those skilled in this art.

At its upper end the inhalation passage I I has a socket I5 for connection to a pressure reducing unit identied in the drawing as P. R. Unit of an oxygen tank shown in Fig. 1 or to an intermediate tube or hose. A high speed nozzle IB having a bore of very small diameter is provided in inhalation passageway I I to increase the speed of flow of the oxygen therein, thereby creating suction in the exhalation passageway I2, which opens into passage II adjacent the ejection end of the nozzle I6, through portal S. As shown in Figure 1, a plug I5 is threaded in the top of the device in alinement with said nozzle to permit insertion and removal of the nozzle. from adjacent the oxygen inlet coupling I5 around nozzle I6 is an inhalation by-pass I'I which also opens into inhalation passage rII through portal S. By-pass I'I insures that an amount of oxygen sufficient for the patients needs will be supplied to the inhalation passage.

As illustrated in Figs. l, 5, and 6 a rotatable Valve R is provided in portal S whereby during insuiliation the passageway I2 will be'cut off and oxygen' be supplied both through the nozzle Iii and the by-pass I'I (Fig. 5), whereas during exhalation by-pass I'I will be closed and the gas exhausted from the patients lung will flow upwardly through passage I2 into passageway II and will be vented through port Hp (Fig. l),

which is closed during insulation by the upturned portion of the slide valve to be described. The means for actuating Valve R is hereinafter described.

A slide valve having a horizontal portion I8 and a vertically extending4 flange portion IB, is provided with the horizontal portion slideably seated in slideway I9 extending across passages II and I2 at right angles thereto, and with the ange portion |81 extending upwardly over the front exterior of the device. In the horizontal portion of slide valve I8 are ports ISa and Ib adapted to register with passageways II and I2 respectively for alternately opening and cutting off communication between passages Il and I2 and the patients lungs. Ports Ia and i812 are spaced so that only one of them may be in register with its passageway at a time, the port that is open being closed and the closed port opened on each reciprocation of the slide.

Upturned portion I8f of the slide valve is adapted to slide over ports IIp and I2p which extend horizontally through the front wall of the device and communicate respectively with the passageways II and I2. In the upturned portion |87' of the slide valve I8 is a port IBp, which at the end of each reciprocation of valve I8 is in register either with port IIp or I2p. During exhalation, when port Ib is in register with passageway I2, ports |810 and Ilp will be in register, and port I2p will be closed; and during insufllation, when port Ia is in register with passageway I I, ports I8p and I2p will be in register and port IIp will be closed.

When rotary valve R is employed to close communication between passageways II and I2 during insufiiation, port I2p is not required. In some cases, however, it is desirable to dilute the oxygen supplied to the patient, and in such cases Extending connected, and valve R employed as a stationary Valve to close passage I1 while port 12p is employed as an air intake port during inhalation.

As illustratedherein the portion of inhalation passageway II between the tip of the nozzle I6 and slide valve I8 is in the form of a Venturi tube, which serves, with the high speed jet of oxygen from nozzle I6, to create suction at portal S to draw the exhalation gases from passage I2 into passage II and expel them through ports IIp and I3p during exhalation (Fig. 6), or to draw air into passage I2 through ports Ip and |212 the means for reciprocating valve R may be disand thence into passage II to be mixed with the oxygen, when valve R is not employed as a reciprocating valve. The nozzle I6 may be screw threadedly fitted into the top of passageway II which is fashioned to receive it and has a bore 2U of very narrow diameter provided with a screen 2| positioned at its upper end to prevent particles of dust and dirt from clogging it. The screen may be held in pla-ce by means of screw cap 22 threadedly engaged within the concavity provided therefor in the top of the nozzle I6. Intermediate the ends of the bore 2 but adjacent the tip of the nozzle I6 an air chamber 23 is provided which communicates, through radially extending ports 24, with passage II opposite portal S. Gaseous fluids from passage I2 or I'I are drawn into the nozzle I6 through ports 24 and ejected through the tip of the nozzle, or drawn through the channel 25 surrounding the periphery of the reduced tip of nozzle I6, between the tip of the nozzle and the wall of the inhalation passageway II. v

Slide-valve I8 is reciprocated by movements of pressure sensitive member 42 induced as will be further explained by variations in pressure in my device corresponding with the pressure in the patients lungs, transmitted through bell crank 3 I, pivoted to the body I0 of the device at 32, and its spring arm 30. After a predetermined degree of rotation of the bell crank 3i about its pivot in either direction, in a manner to be described, the spring arm 3U moves from engagement with one of a pair of permanent magnets 33a and 33h into engagement with the other of said permanent magnets and during the course of this movement engages one of the pins m and n projecting from the face of the slide valve ange I 8f thereby reciprocating the slide valve. The pins m and n are positioned on valve flange I8 so that arm 3l) will not strike either of them when moving in either direction until it has entirely freed itself `from the magnet with which it was last engaged and has gained momentum, so that when the contact occurs the slide valve I8 will be moved sharply and positively the full distance required to open one of passageways II or I2 and close the other. The permanent magnets are slideably mounted in slots 34 provided in bracket 35 secured on the front of the body portion I0 of `my device, so that the distance between each of them and spring arm 30 and its pivot 32 may be adjusted. As illustrated the bracket is a unitary member having outwardly extending anges 36 inclined toward one another in the direction of pivot 32 and secured on the body portion I0 of the device by means of screws 31 extending through the lugs 38 on the bracket. If desired the flanges 36 may comprise part of a continuous shield or cover extending over the ports Ilp and |250, the arm 30, and the permanent magnets 33a and 33h.

It will be noted that, as illustrated in Figure 2, lpermanent magnet 33a is positioned somewhat near-'er pivot 32 than permanent magnetv 33h. Thepressure required to disengage spring arm 30: from permanent magnet 33a will therefore be Vless than is required to disengage it `from permanent magnet 33h'. Spring arm 30 is engaged with `magnet 63a. during exhalation and. it will thus vbe seen that a lesser suction pressure will be exerted on the patients lungs during exhalation than .the positive pressure exerted during insuillation. Very satisfactory results are attained by selecting and positioning the parts of my device so that the contact between arm 3U and permanent magnet 33h will be broken when a positive pressure of 4 ounces per square inch is attained in the patients lungs, and the contact between arm 3i) and magnet 33a will be broken when a negative pressure of 3 ounces per square inch is developed in the patients lungs.

Below slide valve I8 a small pressure equalizing .by-pass- Ais provided between `passages II and I2.` Opening from inhalation passage II 'below slide valve I8 is a passageway 4i) communieating through conduit 4I and coupling 4Ia with the bellows 42 which is adapted to expand upwardly when gas under positive pressure is introduced therein and to deate when the positive pressure is cut off and 'a negative pressure is' communicated thereto. At the top of bellows 42 a pin 43 is provided which `extends through arm 44 of bell crank 3| and has thereon two half spherical lmembers 43a and 43h the spherical surfaces of which engage the opposite faces of arm 4'4. The arm 44 is thus engaged ata point and is capable of some rocking action during the periods-of expansion and contraction ofthe bel'- lows While the positive or negative pressure in the patients lungs and in passages II and I2 below slide valve I8 are building up to the predetermined pressure necessary to move the bellows 4Z, bell crank 3l and spring arm'SIl sufficiently to break the contact between spring arm `attraction of the magnet with which it is in Contact.

The rotary valve R extends through the body portion I0 of the device and as shown in Fig. 2 has the exterior arm orA crank 56, which is slotted at 5I to receive pin 52 fixed on bell crank 6I. Valve R will thus be rotated synchronously with bell crank 3I and therefore with the reciprocations of slide valve I8. If for the purpose of diluting the oxygen supply it is desired to draw air into the device through port |2p and mix it with the oxygen in passageway II during insuiiiation, this may be accomplished by placing valve R in the position indicated in Fig. 6 and the dotted position indicated in Fig. 2, and disengaging pin 52 from slot 5I. To this end pin 52 is desirably provided with annular grooves 52a and 52h which cooperate withV the spring detent 53 in securing the pin 52 in active or inactive position. In Fig. '7, pin 52 vis in inactive position,

The ability of arm 3!) to swing sharply from one magnet to the other is enhanced by spring the upper end of which is attached to pin 4B projecting from the front face of the device near; itsy top, and thelower-.end of whichisseillustrated cured to pin 41 projecting from arm 36 near its lower end. It will be noted that the force exerted .by spring 45 will be greatest when arm 30 is midway between the extremities of its arc of movement and` will thus `accelerate the pendulum-like movement of arm 30 after passingthis point in either direction.

Positioned in inhalation passage II adjacent passage 4] leading to the pressure responsive member 42 is a conical valve 60, Figures 1, 3 and 4, which serves to close conduit 40 and passage II, and open passageways. 6I and 62 lead*- ing to and from an auxiliary gas reservoir -T, indicated in dotted lines in. Figs. land 3 for the purpose of providing an even supply of oxygen during inhalation, when it is desired to use the device as a simple inhalator insteadfof as a resuscitator. The passageways 6I and 62 communicate with conduits 63 and 66 respectively leading to the inlet and outlet ports 64 and 65 of said auxiliary `gas reservoir by means of annular grooves 68 and 68 Vprovided in conical valve (see Fig. 4). At some convenient place, such as the connection to the said auxiliary gas reservoir T, an intake valve 64 is also preferably provided, which opens to admit atmospheric air if for any reason the reservoir becomes exhausted and the amount of oxygen being suplied to the patient through the device is insuftlcient.

It will be readily understood that when gaseous fluid is not flowing into `or out of the member 42 it will be stationary and consequently slide valve I8 and valve R will remain stationary and in order to change the device from use as a resuscitator to a simple inhalator it is only necessary to set valve R to thev position shown in Fig. 1, and turn valve 66 in accordance with the marking on the lower face of the deviceA (see Fig. 2). As shown, valve 6D is yjournalled in a tapered seat 60 which intersects the pase sage II at right angles. A handle 'I2 is secured on offset portion 'II or" valve 6I! and the nut 'I3 is secured on another reduced portion of' the valve at its rear end and abuts against spring 'I4 intermediate it and the rear wall II) of the device to seat and seal the valve 60 properly while permitting its free rotation. Valve 66 is partly cut away at 61 forming a concavity in communication with passage II (Fig. l), and from this cut away portion, a passage 61 extends to the peripheryv of the valve and is brought into alinement with conduit 40 while the device 'is being used as aresuscitator. Adjacent its 'rear end, valve 60 has two partial anf nular grooves or passages 68 and 63' communicating between inlet channel 6I and outlet channel 62 with the respective inlet and outlet conduits 63 and 66 leading to and from the inlet and outlet ports 64 and B5 of auxiliary gas reservoir T while the device is being used as an in-v halator.

When the device is used simply as an inhala` tor, exhalation will be accomplished through a one-way valve in the mask (see Fig. 2)- with which my device communicates. While the device is used as a resucitator this valve is not reflow through passage II directly to the patients lungs and al'sothr'ough conduits 40 andV 4I into` bellows 42 to operate crank arm 3I causing reciprocations of the spring arm 30 as the pressures in bellows 42 is increased during inhalation or decreased during exhalation. In corresponding movements the valve I9 will alternately open and close inhalatio-n passage II and exhalation passage I2. The inhalation passage II communicates with conduit I3 (shown in Fig. 2) leading to mask M which is placed over the patients face and conduit I4 leading from the said mask communicates with exhalation passage I2. When the device is used as a simple respirator the handle l2, shown in Fig. 2, is positioned so that conical valve Eil will be in the position indicated in Fig. 4 thereby closing communication through conduits MI and 4I to the bellows, which is utilized during resuscitation to cause crank 3| and therefore spring arm 30 to reciprocate thus operating slide valve I9 and causing inhalation and exhalation pressures to be built up alternately, but is not needed while the device is used as a simple respirator. Besides cutting off bellows 42, conical valve 60 closes the main passage through the lower portion of passageway II but opens an alternative passage which passes through the auxiliary gas reservoir T. The use of this auxiliary gas supply during respiration insures a reserve supply and therefor an even supply of oxygen irrespective of the evenness of the flow in the upper portion of passageway I I.

While the device is used as a respirator the gas from the oxygen tank passes through passage II, port 6I, annular groove G6 (Fig. 3) in conical valve 60, conduit 63 to the inlet 64 of auxiliary gas reservoir T and from the gas reservoir through outlet of said gas reservoir T, conduit 66, and annular groove E8' of conical valve 6I! and outlet port 62 into the lower end of passage I I, and through conduit I3 to the mask M, shown in Fig, 2, from which it is inhaled by the patient. Gases exhaled by the patient do not pass through the conduit I4 and outlet passageway I2 but are exhausted directly from the mask M through the valve illustrated on the mask and identified as Exhalation valve.

What I claim is:

1. A resuscitation device comprising an inhalation passage adapted to be connected intermediatea source of oxygen supply and a patients lungs, an exhaust passage adapted to be connected to the patients'lungs and an intermediate portion of the inlet passage, valve means positioned below the point of intercommunication between said passages for simultaneously opening one of said passages and closing the other, a pressure responsive member, a conduit leading from said inhalation passage below the saidvreciprocable valve to the said member, said reciprocable valve having a plurality of spaced contact members, a pivoted arm adapted to engage one of said contacts when it is travelling in one direction and the other contact when it is travelling in the other direction, means connected between said pressure responsive member and said pivoted arm for actuating said arm, and means positioned adjacent respective ends of the path of said pivoted arm adapted to engage said arm and hold it until a predetermined opposing pressure is exerted on the arm.

2. An inhalation and resuscitation device comprising an inhalation passage adapted to be connected intermediate a source of oxygen supply and a patients lungs, an exhaust passage adapted to be connected to the patients lungs and an intermediate portion of the inlet passage, an auxiliary inlet passage opening into the inhalation passage at its point of junction with the exhaust passage, valve means for alternately cutting oi communication between said inhalation passage and said exhaust passage o-r said auxiliary inlet, and a reciprocable valve for closing either said inhalation passage or said exhaust passage and simultaneously opening the other passage when a predetermined positive or negative pressure has been built up therein, a duct communicating between said inhalation and exhalation passages below the said reciprocable valve, a pressure responsive member, a conduit connecting said member with the inhalation passageway below the said reciprocable valve, means controlled by the movement of said member for reciprocating both of said valves in synchronism, and means for disconnecting said inhalation passageway and the pressure responsive member and thereby preventing reciprocation of said valve so that the device may be employed as an inhalator.

3. An inhalation and resuscitation device comprising an inhalation passage adapted to be connectedfintermediate a source of oxygen supply and a patients lungs, an exhaust passage adapted to be connected to the patients lungs and an intermediate portion of the inlet passage, an auxiliary inlet passage opening into the inhalation passage at its point of junction with the exhaust passage, valve means for alternately cutting off communication between said inhalation passage and said exhaust passage or said auxiliary inlet, and a reciprocable valve for closing either said inhalation passage or said exhaust passage and simultaneously opening the other passage when a predetermined positive or negative pressure has been built up therein, a duct communicating between said inhalation and exhalation passages Vbelow the said reciprocable valve, a pressure responsive member, a conduit connecting said member with the inhalation passageway below the said reciprocable valve, means controlled lby the movement of said member for reciprocating both of said valves in synchronism,

a gas reservoir, conduits connecting the reservoir with said inhalation passageway below the said reciprocating valve and means for disconnecting said inhalation passageway and the pressure responsive member, thereby preventing reciprocation of said valve so that the device may be employed as an inhalator, and simultaneously connecting said passage with the conduits of said gas reservoir.

4. A resuscitation device comprising an inhalation passage adapted to be connected intermediate a source of oxygen supply and a patients lungs, an exhaust passage adapted to be connected to the patients lungs and an intermediate portion of the inlet passage, an auxiliary inlet passage opening into the inhalation passage at its point of junction with the exhaust passage, Valve means for alternately cutting oli communication between said inhalation passage and said exhaust passage or said auxiliary inlet, and valve means for closing either said inhalation passage or said exhaust passage and simultaneously opening the other passage when a predetermined positive or negative pressure has been built up therein, a duct communicating between said inhalation and exhalation passages below the said valve, a pressure responsive member, a conduit connecting said member with one of said passageways below the said valve, and means controlled by the movement of said member for reciprocating both of said valves in synchronism and means positioned at the respective ends of the path of travel of said pivoted member to engage it with a predetermined force. i

5. A resuscitation device comprising an inhalation passage adapted to be connected intermediate a source of oxygen supply and a patients lungs, an exhaust passage adapted to be connected to the patients lungs and an intermediate portion of the inlet passage, an auxiliary inlet passage opening into the inhalation passage at its point `of junction with the exhaust passage, valve means for alternately cutting off communication between said inhalation passage and said exhaust passage or said auxiliary inlet, and valve means for closing either said inhalation passage or said exhaust passage and simultaneously opening the other passage when a predetermined positive or negative pressure has been built up therein, a duct communicating between said inhalation and exhalation passages below the said valve, a pressure responsive member, a conduit connecting said member with one of said passageways below the said valve, and means controlled by the movement of said member for reciprocating both of said valves in synchronism,

an ,intake port in said exhaust passage, a vent in the device and the patients lungs for actuating said valve including a pivoted pendulum-like arm, means for reciprocating said arm, a pair of magnets positioned and adapted respectively to engage said arm with a predetermined force at the extremities of its travel, and means for opera-y tively engaging said valve and arm during the latters travel in either direction.

y7. A device for mechanically insuiating and deflating a patients lungs including an inhalation channel and an vexhalation channel adapted to be connected between a source of oxygen and the patients lungs, a valve for simultaneously opening one of said channels and closing the other, means controlled by gas pressure within the channel and the patients lungs for actuating said valve including a pivoted pendulum-like arm,

a pair of magnets positioned and adapted to engage said arm with a predetermined force at the extremities of its travel, means for operatively engaging said valve and arm during the latters travel in either direction, a valve in said exhalation channel, and means movable with said arm for operating said valve in synchronism with said rst mentioned valve.

8. A device adapted to alternately create positive and negative pressures in a patients lungs or alternatively to supply gas to be inhaled and exhaled by the patient, comprising, an inhalation passage adapted to be connected intermediate a source of gas supply and a patients lungs, an exhaust passage adapted to be, connected intermediate a patients lungs and said inhalation passage, a slide valve extending transversely of said inhalation and exhaust passages having a port therein adapted to register alternately with said passages, a vent in the wall of each of said passages, means for operatingsaid valve member, and means actuated by said valve for closing the vent in the passage with which the port in the said slide valve is in register.

9. A device adapted to alternately create positive and negative pressures in a patients lungs or alternatively to supply gas to be inhaled and exhaled yby the patient, comprising, an inhalation passage adapted tobe connected intermediate a source of gas supply and a patients lungs, an exhaust passage adapted to be connected intermediate a patients lungs and said inhalation passage, a slide valve extending transversely of said inhalation and exhaust passages having a port therein adapted to register alternately with said passages, a vent in the wall of each of `said passages, and means actuated by said valve for closing the Vent in the passage with which the port in the said slidevalve is in register, a pressure responsive member, a conduit connecting said pressure member with said inhalation passage, and means controlled by the movement of said pressure member for reciprocating said slide valve.

10. A device adapted to alternately create positive and negative pressures in a patients lungs or alternatively to supply gas to be inhaled and exhaled by the patient, comprising, an inhalation passage adapted to be connected intermediate a source of gas supply and a patients lungs, an exhaust passage adapted to be connected intermediate a patients lungs and said inhalation passage, valve means for simultaneously opening one of said passages and closing the other, a pressure responsive member, a conduit connecting said pressure responsive member with said inhalation passage, and means controlled by the movement of said pressure responsive member for actuating said valve means, and a duct communicating between said inhalation and exhalation passages, said duct and said conduit connecting the pressure member With the inhalation passage being located on the same side of said valve means.

11. A device adapted to alternately create positive and negative pressures in a patients lungs or alternatively to supply gas to lbe inhaled and exhaled by a patient, comprising, an inhalation passage adapted to be connected intermediate a source of gas supply and a patients lungs, an exhaust passage adapted to be connected intermediate a patients lungs and said inhalation passage, valve means for simultaneously opening one of said passages and closing the other, a pressure responsive member, a conduit connecting said pressure member with said inhalation passage, and means controlled by the movement of said pressure member for reciprocating said slide valve, a chamber for storing oxygen, a conduit connecting said inhalation passage to said chamber, and valve means for alternately closing one of said conduits and opening the other.

12. A device adapted to alternately create posi,- tive and negative pressures in a patients lungs or alternatively to supply gas to be inhaled and exhaled by the patient, comprising, an inhalation passage adapted to be connected intermediate a source of gas supply and a patients lungs, an exhaust passage adapted to be connected intermediate a patients lungs and said inhalation passage, a slide valve extending transversely of said inhalation and exhaust passages having a port therein adapted to register alternately with said passages, a vent in the wall of each of said passages, and means actuated by said valve for closing the vent in the passage with which the port in the said slide valve is in register, and an additional inlet for supplying gas, opening into the inhalation passage at its point of junction with the exhaust passage, and valve means for alternately connecting said additional inlet or said exhaust passage to said inhalation passage.

13. A device adapted to alternately create positive and negative pressures in a patients lungs or alternatively to supply gas to be inhaled and exhaled by Va patient, comprising, an inhalation passage adapted to be connected intermediate a source of gas supply and a patients lungs, an exhaust passage adapted to be connected intermediate a patients lungs and said inhalation passage, valve means for simultaneously opening vone of said passages and closing the other, a pressure responsive member, a conduit connecting said pressure member with said inhalation passage, and means controlled by the movement of said pressure member for reciprocating said slide valve, a chamber for storing oxygen, a conduit connecting said inhalation passage to said chamber, and Valve means for alternately closing one of said conduits and opening the other, an additional inlet for supplying gas opening into said inhalation passage at its point of junction with nthe exhaust passage, and valve means for alternately connecting the inhalation passage to said auxiliary inlet and to said exhaust passage.

HORACE H. RAYMOND.

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