US2383181A - Apparatus for inducing respiration - Google Patents

Description

M 11, 1945: H. E. ENSLIN ETAL 2,333,131-

' APPARATUS FOR INDUCING RESPIRATION F i led Jan. -29, 1945 2 Sheets-Sheet 1 //v VE/V 727E251 HERBERT E. E/YSLl/V saengvyc. 234M205 A TTOfP/YE vs H. E. ENSLIN ETAL 2,383,181

APPARATUS FOR INDUGING RESPIRATION Filed Jan. 29, 1945 2 Sheets-Sheet 2 M Wwm W E WW O F T R m E5 glZ' A &

sm mm w 7 R m Patented Aug. 21, 1945 e 2,383,181 a APPARATUS FOR INDUCING RESPIBATION Herbert E. Ensun, Beverly,

Mass and Edgren C.

Wallace, Miami, Fla., assignorsto Revair Cor-- poration, Boston, Mass.,

chusetts a corporatiori'of Massa- Applicatio n Janua ryi29, 1943, Serial No. ii4, 020

4 Gianna, (01. 128-29 This invention relates toapparatus for administering oxygen-containing.orother gases to the lungs forthepurpose of restoring normal respiration; and pertains more particularly to improvements in portable, manually-operated, me-

chanical respirators intended to be used in lieu of or as an adjunct to well known methods of manual resuscitation.

The principal purpose of the, invention is to.

provide a safe, efficient and relatively sirnpledevice which may be readily transported and easily operated by a laymamwhich will supply, to the lungs either fresh air, pure oxygenor gaseous mixtures, under controllableconditions of volume and pressure, and which will withdraw relatively smaller proportions ofexpendedgases until the lungs are adequately inflated and natural breathing has been induced! we are aware that ,various types oipulrnotors, mechanical resuscitators and other respirating devices have heretoforebeen devised, but itiis commonly known that such devices have m'etwith the disapproval of the ,medical profession for general usage because they could not be regulated or controlled toQin'duce' pulmonary ventilation under conditions; of, time, volumdand pressure approximating natural, respiration of the individual being treated. It has been found that these prior devices creatabnorrnal conditions and Ea ie ratory tract {by overdistention funder excessive positive pressures on forced inspiration, and by harmful contraction .under I excessive negative pressureson forced expiration. A further objecb the ,pressure-and-suction type of appara I tus has been the inability of such devices to afford anadequate exchange of gases because of the too raprd constriction of the alevoli and bronchia.

Itis riowfecdgnizedthat. resuscitation after asphixia orfthe restoration of natural respiration after failure for other causes is primarily achemlcal, aetion involving a renewed supply of oxygen which stimulates circulation, improves the tonus and elasticity of the, diaphragm and thoracic muscles and inducesmormal pulmonary ventilation, Hence, satisfactory results maysafely be achieved by, administering oxygen-containing gases to the lungs under natural conditions of time, volume and pressure, without employing the excessive quantitiesand pressureswhioh were considered necessary to accomplishthe results mechanical phenomena, is understood, nevertheless, that the" gases administered to the lungs are absorbed or diffused through the tissues;

injure the tissues of the lungs and respiaccording to the mechanical principles applying to inflated bodies having capacities and surface tensions comparable to the lungs. s 5 i i The improved apparatus which we 'have devised has been designed after extended research.- or the physiological conditions affecting artificial respiration and the mechanical requirements necessary to satisfy those conditions; and .itriS the main object of this invention to obviatethe objectionable features and harmful effectsof the prior devices, and to provide means for so-ade justing and controlling'theoperation of our inachine that its rate or operation, and the volume and pressure of gases delivered to or withdrawn from the lungs, will approach as nearly as practica-ble to the individual physiologic conditions of natural breathing-even when the: machine manipulated by an inexperienced operator.

Thisobjective is attained loy equipping the improved machne with controls which ensure gradual inflation of thelungs with fresh air supplied in safe quantitiesat harmless pressuresand in"- itially withdrawn in substantially smaller quantities at lower pressures, creasing minimal supply remains in the lungs; and which permit expirations of larger amounts atilhigher pressures after the lungs have been filled to such an extent that muscular reflex expels theexhausted air. Thus, normal respiration is induced and maintained while the machine is being operated and without further ad'- justment of its controls. 1

These and other salutary features of the improved apparatus will become apparent from the .following description of theconstruction and operationoi the recommended embodiment of the invention shown in the accompanying drawings, in which: A

I Fig. 1 is a perspectiveview of our apparatus, with a portionof thecontrol compartment broken w y; 3 H r Fig. 2 is a vertical section of the machine taken on lineII of Fig. 3, with certain partsjin ele'vation;

Fig. 3 is a horizontal section on-line ill-111 Figs. 4 to 9 inclusive are detail section. views taken onlines IV, V, spectively, of Fig, 3; y

Fig.10 is'a developed view in perspective of the parts of the bearing and loclrmechanisrn at vr, v11, vnr and ixg e the top of the central cylinder in Fig. 2;

adjustable valve mechanism at the bottom central cylinder of Fig. 2; and

detail of an of the Fig; 11 is an enlarged sectional so that a gradually in-- Fig. 12 is a perspective view to larger scale of an air-filter shown in Fig. 7.

In the particular embodiment chosen for the purpose of illustration, the improved mechanical respirator is of the hand-operated pump type, comprising in general a pressure cylinder, a suction cylinder, an intermediate cushion cylinder acting as-a pneumatic brake for controlling. the speed of reciprocation of the pistons moving in said cylinders; an operating handle connected to the three pistons; are mounted, having ports and check'valves regulating the admission and discharge of air or oxygen-containing gases to andfrom the cylinders; an adjustable valve for controlling the rate ofreciprocation of the piston in the brake cylinder; manual valves controlling the supply of pure air, oxygen or mixtures thereof, to the zles associated suction cylinders, to which tubes leading to a suitable face mask may be attached, the twonozzles having openings substantially different indiameter for a purpose hereafter explained; and. a control chamber having vents disposed in the conduit between the respective nozzlesand the corresponding cylinders, and manually controlled valves simultaneously operable to open or close the vent openings and thereby regulate both the volume and pressureof the gas delivered. to the lungs or withdrawn therefromv by' the; operation of the machine.

The base 2| of the machine may be a. metal casting providing a bridged opening for receiving the operators foot which bears upon a bottom plate 22. be made of-metal, preferably plated on the inside to avoid corrosion, or of other suitable material. The} are suitably mounted in pright position on the base 21, and the lower portions of. the cylinder are preferably shielded and reinforced by a casing 26 of plastic or the like. The control chamber 2'! is mounted on thebaseagainstv the shield 25.

In the aligned arrangement shown, 23 is the pressure or inspirating cylinder, 25 is the suction or expirating cylinder, and 24- is. thebrake or stroke control cylinder; but it will be understood that. the cylinders may be disposedin other formations if. desired. Each cylinderhas a suitable piston and rod as shown in. Fig. 2, thepistons having suitable compression; rings, the rods being tubular and having vent openingstopermit free circulation of ai-ra-bove the pistons asindicated in said figure; and each of the operating cylinders has a capor head afiordinga bearingforits piston rod. The brake cylinder 24 has a packer head providing a releasablelock for the operating handle as hereafter described.

The upper ends of the piston rods are connected to a handle 28 for reciprocating the three. pistons simultaneously, and the bottom portion of the handle is provided with a bridge-like latch member 29 having flanged legs 30 -(Fig..10.) releasably engaged by the inturned lugs 3| of a locking ring 32, to hold the handle andpiston rods in downward or closed position when the apparatus is not, in use (Fig. 2). As best indicated in Fig. 10, the locking ring turns about the-threadedstem of a packer head 33 which screws into the top of cylinder 24 a nut 34' holds the-ringv against -displacement whilepermitting itsrotation by hand; and a tapered bushing, 34 and packer head nut 35 threading on the packer head 33 .to provide a relatively tight bearing for the piston rod ot the stroke control cylinder. Downward movement of i a base on which the cylinders machine; nozwith the respective pressure and The three cylinders-.23, 24 and 25 may thereto by a lock nut 37.

the handle is limited by its engagement with the hubs of the caps on cylinders 23 and 25 (Fig. 2).

The base of the stroke control cylinder 24 is fitted with an internal nut 36 (Figs. 2 and 11) having adepending end projecting through the top portion of the base member 2| and secured Said nut end and locking member have vent openings 38and 39, respectively; and an orific'ed. screw 40having a valve tip 4| threads in the upper end of the nut 36 to open or close the opening 38 and thereby regulate the flow of air through the screw orifice 42 and beneath the brake piston.4'3. In Figs. 2

' and 11 the adjustable valve is closed, but it will be matic cushion which obvious manner 5| and.52. v p pure air, and is provided with. a filter. comprising understood that the screw 40 may be turned to open the port 38 to such extent as may be desired.

It will also be evident that the adjusting valve must be regulated-before the piston 43 is placed in. the cylinder 24, so that the adjustment cannot'be changed without dismantling the ma chine. Hence, the machine may be tested and regulated at the factory until the brake cylinder performs its desired function of affording a pneuprevents abrupt operation of the handle 28'and tendsto control the spcedof reciprocation to the desired rate of about six-- teen to twenty strokes per minute. If desired, a check valve (not shown) may be employed inan to close theorif ce 42 in the-upstroke of piston 43.

The admission, of pure air, oxygen: or other gases, or mixtures thereof, to the pressure cylinder 23. is regulated by a. pair ofv valved inlet ports Port 5| (Fig. 7') isintended to supply an apertured tube 53. containing a. sleeve 54 0ffelt or other suitable air-filtering. material; and a spring 55 for retaining thefelt sleeve mpropfe'r' position within the tube. The-valve or. took of this port is regulated. by ,a knob. 45v (Fig. 3) which may have suitable indicationsto designate its setting. W p

Gas-intake ,port..52 (Fig-5) has a hose connector 56 for the attachment of a tube. 51 leading from a tank'containing oxygen or. QthergaSes to be administered to the lungsjiand-aknob ,58 for regulating the valve opening. -It will be understood that either port may be used, separately, or that both ports may be simultaneously employed to supply any oxygen (or other gases); and it will. also be ap-T parent that the valves of both ports. may be controlled by a single regulating knob, if desired. I These intake ports communicate with cylinder 23 through ducts 59 and 60, respectivelmjthe openings in the base of. the cylinder' being equipp d with ball check valves BI and62, re-, spectively, whichpermit thesgases to enter 'the cylinder on the upstroke of pressure piston 63 but seat on the downstroke thereof. Thegdischarge port 64 of the pressure. cylinder (Fig. .8) communicates through duct 65 and ball' check valve 66 with a pressure (regulator chamber 61 located in the control chamber 21; said regulator having a small vent opening 68 (Fig. 4) controlled by a needle valve or plunger 69, and a larger outlet port communicating through a nipple 10: with a nozzle H to which a tube of 1 the face mask may be fitte A safety valve 12 is located in the duct: between the regulator 61 and: the hose connector H, the ball valve 12 being of such weight that it will open under pressures exceeding 25 mm. (Hg) above atmosphere, at the lung. A Whistle signal 13 is located above this. escape valve so desired mixture of air land that the operator is warned when the pressure exceeds the maximum valve for safe operation of the machine. i

The base' of suction cylinder 25 (Fig; 6) has an inlet port I equipped with ball check valve 16 and communicating through duct 11 with a suctionl regulator chamber 18 located in the control chamber. .This regulator has a vent opening 19 regulated by a plunger or needle valve '80: (Fig. 4), and an intake nipple 8| I equipped with a hose connector 82 to whichthe port expels air (and also any water or mucous which may be drawn into cylinder on the downstroke of the suction piston 86 (Fig. 2), when thevalve 84 is opened by pressure of the exhausted gas within the cylinder-25.

The needle valves 69 and 80 (Fig. 4) in the control chamber, are simultaneously actuated in the same direction and to the same degree, by a cam 9| which bears against a plunger. bar 92 attached to both valve plungers. Thecam shaft 93 is rotated. by a regulating knob 94 located outside the chamber 21 (Figs. 1 and 3), and the bar .92 is held against the cam'by a spring 95 connected thereto through a yoke 96, and attached at its other end to the top portion of the base memberZl (Fig. 4). erably has four rises as'indicated in Fig. 4, giving four adjustable positions of the pressure control valves, and these positions may be indicated on the pressure control knob adjuster 94.

Adjustment of these control valves 69 and 80 enables the user of the apparatus to control both volume and pressure of the gases delivered by the positive pressure cylinder 23 or exhausted by the negative pressure cylinder 25,'by venting to atmosphere a predetermined proportion of the air or gas passing to the lungs through outlet nozzle II or withdrawn from the lung through intake nozzle 32. Such adjustment is necessary to supply the correct volume and pressure for the lung capacity of the patient as determined by his age or physical condition, and the adcontrol valves, or endeavor to remove any such obstructions." Hence, the three controls upon excessive pressure supplement each' other and cooperate in ensuring that the respirator may be efficiently operated at normal speed without injury to the patient due to excessive pressures.

-It will be noted 1 that the adjustable control valves 69 and 80 operate simultaneously to re- .duce both volume andpressure on the expirating stroke as well as on the inspirating stroke of the respirator..' For the reasons previously explained, it is very importantthat the negative pressure created by the suction cylinder 25 be reduced proportionately to anyreduction of positive 23, so that the pressure down stroke in cylinder differential between the positive and negative sides of the. apparatus be maintained particularlyduring the early stages pressure created by the -of operation.

The cam 9| prefjustment may obviously be made during operation of the apparatus as well as in advance,

merely by turning the regulating knob 94. The machine and its controls are preferably so constructed and adjusted that the maximum volume of air or gas delivered by the pressure cylinder (with the valve 69 closed) is approximately 500 cc. at a pressure in the vicinity of 25 to 30 mm. (Hg) above atmosphere, at the lungs; and that the minimum volume is approximately 109 cc. at a pressure of about 5 mm. at the lung. Intermediate conditions will depend upon the setting of the regulating knob.

It will be understood that this volume-pressure control operates independently of the stroke control and of the safety valve, but it will be appreciated that excessive positive pressures, caused either by too speedy operation of themachine or by obstructions in the throat, larynx or trachae, will immediately be relieved by the safety valve and the whistle signal will warn the operator to reduce his speed, regulate the Such pressure differential (and. complemental volume differential) is influenced by the relative sizes of the openings 9! and 98 in the hose con nectors B2 and 1|,respectively, by the provisions of expansion chambers in the regulators 'ls and 61 (Fig. 4), and by the drop in pressure withinthelungs and tubes of the patient when a collapsed lung is gradually filled on successive in spirating strokes of the machine. It will be apparentfrom Fig. 4 that the opening in the connector 82 is. substantially smaller than that in connector", preferably in the proportion of one to four in cross-sectional area. The differential caused by the relative size of the openings 91 and l flis, however, overcome after the lungs have been completely expanded, so that the muscular contraction of the diaphragm will thereafter ex pel a. volume of air substantially equal to that delivered by the apparatus, at substantially the same pressure. .Thus normal breathing is .in-

duced and. maintained even though the patient is still unconscious. This condition will normally be reached after thirty to forty strokes of the machine, and thereafter normal tidal exchange of fresh air is uniformly maintained until the patient recovers.

It will be appreciated that optimum results of the use of the improved'respirator will depend upon the size of the ducts or conduits between the respective operating cylinders and their hose connectorsand upon the weight of the balls or other valve elements in the safety valves and the check valves, particularly ball valves 12 and 1B. The former should release, as aforesaid, under positive pressure of about 25 to 30 mm. (Hg) above atmosphere, and the latter should unseat at a negative pressure of approximately 6 to 8 mm. Thus, when the pressure cylinder initially delivers about 500 cc. of fresh air (or other gases) to the lungs at 25 mm. pressure, the first/upstroke of the piston will withdraw approximately 125 cc. of exhausted air from the lungs at a negative pressure of about 7 mm. Under succeeding inspirating strokes the volume of residual air in the lungs is gradually increased and the quantity withdrawn is also progressively increased under successive expirating strokes, until a normal tidal exchange of the average volume of 500 cc. is induced as aforesaid.

Such gradual filling up of the lungs, coupled with the safety factor alforded by the relief valve 12, the limitation on the speed of operation and the adjustment permitted b the pressure control even though the respirator is operated by an ineicperiencedtperson. The deviceaherein;described may bez manufactureds at reasonable cost; it is small; compact, and-portable; it is easy to operate emciently: under" simple; instructions which; may benpaclced- Wi'thathesv machine; andait may beused confid'ently ands-safelyin any: cases of" asphixia', d'llH'ibOiDGfSDIIQUSi gases; electric. shock; water submersiom ortheflikap a Wevciaimaz? 1-. In; respirating: apparatus of: the character described: having: a pressure cylinder, a suction cylinden andrzoutlet andzintake ducts leading from thG-LIESDEQHVET cylinders to: inspirating and expinatin'g li'ose'connectors; pressure control means comprising movable-r valves operatively disposed im the respective: ducts; said ducts having: vent openings-z. controlled by said: valvesr topermit; the escape of air' therefronr when; the valves" are opened, a bar interconnecting said valves; a cam engaging said bar; and manually-operable'means for-rotating said camx to simultaneously regulate both valves; r

v2. In" respiratingapparatus of the character described having a: pressure cylinder; a suction cylinder and outlet and intakeoucts leading from the respective cylinders 'toinspirating and expirating: hose" connectors; a stroke control cy1.-'

indervhaving' an apertured valve member-in: its base, and a valve-closin'gZ-screw threading downwardly-v into said. member; whereby the valve opening may-be= regulated by turning: said screw only-"Whenrthe cylinder is open; each: oftthe' three having pistons and piston: rods; and

cylinders the three; rods being; connected to an operating handle; so that the rateof movement of" the pistonst inythe pressure andsuction cylinders is governed 'bythe rate of movement of thepiston'in the control cylinder.

3. In respirating apparatus of the character described having. a pressure cylinder, a' suction cylinder; and; outlet andrintake ducts leading from the: respective; cylinderstoinspirating: and; expirating hose connectors, a controkchamber: dis-,- posed adjacent! the: bases of said cylinders-and containing aportionaof each; of said ducts,:.said ducts having; vent:- openings; disposed within said chamber, andv pressure control means: comprising movable valves operatively disposed: in the; re:- spectiveducts. and regulating; the. escape-of: air through the; respective vent openings; alinkdnxterconnecting said.valves;. and a valve actuator engaging-:- said link,-. through; the compartment walland. having an operable-handle accessible outside the" compartmennp whereby bothi valves are simultaneously regulated in\ unison by turning the handle;

45.. In: respirating: apparatus of the character described: having. a: pressure cylinder;. a: suction cylinder andoutlet andaintake ducts leading-"from the respective cylinders to inspirating' and: expirating; hose: connectors," a control chamber disposedadjacent thebases: of. said" cylinders and containing axporti'on of each of said ducts,-said ductsshaving vent openings disposed within said chamber; andzpressure: control means comprising movable valves 'operativelyv: disposed; invthe respective ducts and regulating the escape of" air through the respective ventiopenin'gs; a link in:- terconnecting said valves,v ai'sprin'g connectedirt'o thelink-and-stendingto: move: the valves to vent closing position, a: cam engaging said link. for opening the valvesgpandi a rod extending through the: compartment. wall and having a, knob accessibleoutside the.- compartment, whereby both valves: are simultaneously regulated in' unison by turning theknob.

HERBERT ENSLIN. EDG-REN' o; WALL CE:

said: actuator extending

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