US2907325A - Venoclysis equipment - Google Patents

Description

Oct. 6, 1959 BURKE 2,907,325

vEN'ocLYsIs EQUIPMENT Filed Nov. 2'7, 1953 2 Sheets-Sheet 1 GEORGE K. BURKE ATTORNEYS Oct. 6, 1959 s. K. BURKE VENOCLYSIS EQUIPMENT 2 Sheets-Sheet 2 Filed Nov. 27, 1953 GEORGE K. BURKE ATTORNEYS United m VENOCLYSIS EQUIPMENT ice 'Wh'en such additionalpressure is put on the liquid,

George Kenneth Burke, Bethlehem, Pa., assign'or to I Laros Company, Bethlehem, Pa.,

a corporation of Pennsylvania Application November 27, 1953, Serial No. 394, s1-

This invention relates to improved venoclysis equipment. More particularly, it relates to venoclysis equipment which can be used, without structural modification; for administering injection fluids under normal conditions and for rapid, forced injection o'rfeeding of controlled:

. In administering injection fluids, such" as in the in-- increased amounts of fluids in a given time period.

travenous injection of plasma 'or plasma substitutes or extenders, under normal conditions the fluid is allowed to flow into the vein by gravity at a comparatively slow but steady, sustained rate. However, in cases of emergency, it isnecessary to force copious amounts of the fluid into the vein,-as for instance when the patient has lost a large amount of blood.

The venoclysis equipment available heretofore consists of a length of tubing having a hypodermic cannula on one end thereof, the other end being adapted for insertion into or connection witha container for the fluid which is also providedwith an air inlet or so-called air-Way cannula. for introduction of the air-required to displace fluid in the container and initiate flow thereof into "the tubing. .The device also comprises a slotted flow control member, in which the slot is graduated and which is adjustable transversely of the tubing to vary the crosstubing connected therewith, and the needle, are com-- pletely purged of air, theneedle is inserted into the patients vein, and the fluid is allowed to flow bygravity into the vein.

As long as the conditions are such that the liquid flows into the, vein by gravity and it is not necessary to in crease the flow of the liquid into the .vein to a greater degree than can be. elfected by adjusting .the position of the slotted member on the tubing, no great' problem arises.

The problems arise when it becomes necessary to force a substantially increased amount of the liquid into. the vein during the feeding. This can only-be accomplished by increasing the pressure on the liquid from an external source, that is by pumping air into the bottle or the like through the air-way cannula and upw'ardlythrouglr the shield surrounding the cannula and terminating above the"; level of the liquid in the bottle. .When this is.done,1air may follow the liquid into the vein. ..This is extremely; 65

I cially when it .is read in conjunction dangerous, for as is known even a small amount of air in? jected intravenously is suff cient to induce severe or;fatal air embolus. This is an everpresent hazard which ac-.v counts for the attentive watch maintained during in.-':

travenous feeding when the pressure on the liquid in the bottle is increased and the air or other gas pressuremay.

be so great that air can follow the liquid into the vein.

the pra'cticeis to withdraw the needle from the vein as soon as. the level of the liquid drops below the bottle mouth? Under those conditions of increased pressure, there is also the possibility of air (or other pressurizing gas)' being dissolved in "the liquid 'and'injected into the vein with it. v V

Despite'the maintenance of constant attendance, it is not infrequent for severe or fatal embolism to develop in a matter of several seconds if there are air bubbles in the line and additional pressure is put on the liquid. The {practice is to watch for' the air bubbles and if any are detected to, withdraw the needle immediately from the vein, purge the supply line of the air, and reinsert the needle. Thisistime-consuming when time may be of the *essence in saving the patients life. Moreover, the repeatedinsertion of the needle is painful and may be dangerous. :Furthermore,-repeated purging of the tubing, after' it has been in use, results in loss of valuable fluid and, asthe purging is usually performed, the fluid -is'spray'ed over the' floor and equipment of the room Another disadvantage is that, after each purging, in order tostart'the fluid flowing again, additional air must be introdu cedinto the. container. It is practically impossible at; avoid the introduction of contaminants with the air and these contaminants are not all removed by the usual filters such as those of cotton, when used under pressure. The known equipment also has the disadvan- Where the'patient is being treated, leading'to messy contage that back-flow of the'fluid, due to venous pressure,

may cause interruption of the feeding and require removal and reinsertion of the needle with all the difliculties and hazards that presents. There is still another objection to be mentioned in connection with the venoclysis equipment currently in use. It is thisrif the injection needle becomes obstructed, normal saline solution must be injected into the tubing, adjacent the needle, to dislodge the obstruction. I

One object of this invention is to provide new and novel venoclysis equipment which can be used both for injecting fluid under normal conditions requiring the steady delivery, by gravity, of a relatively thin stream of the fluid, and under conditions where large amounts of the fluid must be injected rapidly without danger of entrain- -'-ment of air in the liquid.

Another object is to provide equipment of the type stated in which the increased amounts of fluid injected into the vein can be controlled very readily and administeredin a given time period which can be predetermined.

A further object is-to provide transparent, disposable venoclysis equipment which can be readily deaerated before the feeding is commenced and iniwhich, thereafter, the existence of a partial vacuum reliably, prevents passage of air'wi'th the fluid to the needle.

A still fiurther object is to provide venoclysis equipment in which back-flow due to venous pressure is relived as soon as'it develops. h

Another object is to provide equipment such that if an obstruction, such as a venous clot, becomes lodged in the injection needle, it can be quickly dislodged by means of pressure exerted at the appropriate point along the length of the tubing.

'I.-'h es e, andother objects-and advantages will be apparent from the detailed discussion which follows, espewith the attached drawing; in which-:-

Figure. l is a front elevation of invention,

Figure 2 is a sectional view taken on line 2-2 of Figure 1,

one embodiment of the 3 Figure 3 is a sectional view taken on line 3-3 of Figure l, n H

Figure 4 is a sectional view taken on line 44 of Figure 1,

Figure 5 is a, top. plan view of a compressing device; Figure 6 is a front elevation. of; a modification of, the.

valve structureshown. inFigure L,

Figure 7 is a, front, elevation. of'another, modification,

a modification, shown.

ous channel for injection fluidflowing, by gravity from av source of supply to a. hypodermic cannula and.including, disposed along its length and. as, at least: in.- effect, an integral part thereof, a pump and check valve system for.

increasing the rateof flow. of. the fluid to the needle at;

will. The essential elements of the: new venocly sis equipment are a; drip tube, an. ohservationhousing enclosing: the drip tube and, having an open bottom, checkvalves, a.

pump and. alength of tubing having across-section smaller than the pump and adapted to receive on one end thereof-,

the hypodermic cannula, these. elements being interconnected in the order named. to provide the continuous, channel and the pump-being compressible, preferably manually, transversely of. thelongitudinal axis of, the equip-- ment, to actuate the check valves, thereby interrupting,

flow of the fluid to the. pump and forcing the fluid into. the needle. p

In, the preferred embodimenh the equipment is made.

wholly, of transparent plastic, material. Since it. is preferred to have the drip tube, observation housing, and valves relatively rigid, while the narrow tubing feeding directly to the needle is preferably more flexible and resilient to allow for thenecessary play. when, the needle.

is inserted in the vein, and the pump must be compressible transversely of the axis of the. equipment and suflicient-ly resilient to rapidly return to normal expanded. condition when: the compressing force is removed, it may be desirable, to moldthe parts separately, from ditferent plastic materials, and to join them together to form the continuous channel for the needle-by meansof relatively rigid plastic adaptors. and short lengths or couplings; of;

the more flexible, tubing' Throughout, the plastic ma terial must be effectively resistant to the, chemicalaction, of any of the fluids which would ordinarily be conducted therein in connection with, intravenous and like injec:

tions and capable of withstanding heat or cold sterilizertron without damage or: any noticeable softening, It,

should also be a material which can be. produced in the form of tubing having smooth innerand outer surfacesand a high degree of uniformity" in. respect, to its internal. and external diameters.

Polystyrene is tough, transparent, relatively rigid, and. may be used to form the: drip tube, observation housing,

check valves and adaptors. Other materials which meet.

the requirements may be used, however. For the more flexible, narrow tubing and the compressible pump,.plasticized polyvinyl chloride (which sho uld preferably have, a limited lead content not greater than 15 parts of lead/million) iseminently satisfactory, but other therm'o The invention is, not limr' ited to use of any particular transparent plastic materials plastics may be found. useful;

having the properties' mentioned,-- and is contemplated that all parts of the equipment may be molded of the same plastic material: in a;si:ngle molding operation:

Referring now to Figure 1, there is shown a-hottle-z the lower end ofrwhich is provided with a metal band 3 to which is pivotally connected a wire bail 4 hywhicli the bottle 2 carrbe; mounted: for use in inverted position upon a support, asupon the hook 5; The bottle disthe drip tube 6 in the observation tube or housing 7. The tubular adaptor, drip tube 6, and the observation tube 7 are made of clear, transparent polystyrene so that the dropwise discharge of the fluid into the housing 7 can be observed. The bottle is normally sealed with a puncturable seal, preferably of-asoft material adapted to substantially close a. puncture after the puncturing instrument is withdrawn, and the forward end of the bottle adaptor, which is preferably pointed or beveled, renderingitneedle-like to facilitate puncturing of the seal thereby, extends upwardly through the seal into the fluidin .the bottle. The bottle; is provided with the. usual air-way cannula 6a surrounded by a shield 6b which extends upwardly through the bottle to a point above the level of the liquid when the bottle is in the inverted position.

The observation tube; 7 is. connected with check valve 8,: pump 9., check valve 10, and the length of narrow flexible tubing 11 having needle; llmounted onsleeve: 13 supported on, the rearward or lower end; thereof, through aseries. of hollow adaptors 14,. 15,,16, 1-7, 18,19, and 20 ..and relatively shortlengths. or couplings of flexible tub-., 25

ing-Z1,,22, and ZBint TWhichthe-ends of the. adaptors of redueeddiameter, project-,,-to3provide acontinuouszchannel through: which the-fluidflows'from, the bottle 2' to, theneedle 12. v 1

Adaptors. 1'5'and 16,. associated, with. the. tubular morn-- ber. 24, constitute the chechvalve- 8, the. adaptorslS and. 16being, the inletandoutletcof the; valve, respectively... Enclosed by the adaptors and; member; 2.4,. and; as shown. in. moredetail in Figure 3., is; a-. seamless; check ball 25 ofsoft, resilient.material,v suchas surgical rubber or plas- IiG.WhlCh,-il1, normal; use: of the. equipment, floats in the fluid and is: restrained in its. downward movement by the lugs.v Z6 projecting; inwardly from. the internal wall. of member 2.4; so thatpassage. of the fluidthrough the equip-- .:ment is; not impeded; thereby. Adaptors. 19=an l 20, to-

gether with tubular member 28,: constitute the check valve 10 The. valve comprises the seamless check ball 29 of soft resilient material: such. as surgicalv rubber-or plastic. 111::the normal; use of the equipment, ball: 29 floats inthe fluid; passing, through the valve and is restrained in. itsdownwardg, movement by lugs or restraining members projecting inwardly.- from the inner wall ofv member 28- so-thatithe, channelin adaptor 20 remains open for corn tinuous gravity flow of the fluid into the tubing 11. The restraining; members. may be of atype such that those members, function asfilters forthe liquid passing through th.e -.valve From the valve. 10, through adaptor 20 forming the outlet; thereof, the. fluid passesinto. the narrow flexible tubing 11 (shown broken in Figure l) which may be of any suitable length but is. usually quite long, and thence into the needle. Instead of supporting: the. needle directlyon-the plastic tubing, an intervening cuff of softresilient material; preferably surgicalw rubber, may be providedwhen, as; issometimes the case, it is desirable or necessary to inject, periodically, a second diiferent fluid intothe vein simultaneously. with: the fluid flowing from bGItleLZLf in. the. device illustrated, the tubularbottle adaptor, dijp; tube, observationhousing, valves, and adaptors were all;- molded from polystyrene, while the. pump, flexible couplings. and, tubing 11 were extrusion molded from plasticized: polyvinylchloride. When these two; plastics aresheldrintcontaet with each'other, thereis a tendency tolchemi'cal reaction which-may involve plasticizers presenti 'In 'thi's instance, or in the 'caseof any other two materials fromwhich the respective parts-may be molded whenrthere is a: likelihood of chemical reaction taking place,-,and-'-such' chemical reactionisnot desired, the inner surface of the tubing, or theoutersurfacesof'theadaptors, over'theiarea of contact between the surfaces, may

be coated with' aliquid substance or composition'which, on drying forms an inert barrier between the surfaces whereby the chemical reaction is prevented. In the em,- bodiment illustrated, the outer surfaces of the polystyrene parts which would normally contact with plasticized polyvinyl chloride were coated with'the commercially available product Logaquaint (a transparent or ambercolored resinous liquid having a flash point of 120 F. at 7.6 lbs. solids/gal.). Other eflective barrier substances may be used. After drying of the barrier coating or film, the ends of the couplings, and the end of tubing 11, may be spread in any suitable way, the reduced ends of the adaptors fitted therein, and the spreader removed so that the'tubing grips the coated portion of the adaptor to hold the latter firmly in position in the tubing.

The polystyrene adaptors may be cemented. to the observation housing and tubular members 24 and 28, by means of any suitable plastic cement.

The equipment comprises the usual flow control means in the form of a plate-like member 30 made of sheet metal, aluminum or the like and provided with tapering slot 31 through which the narrow flexible tubing 11 passes. By adjusting the slotted member 30 transversely of the tube, the tube is more or less closed as it is moved into the narrow end portion of the slot thereby to resist the flow of the fluid. At the wider end of the slot, which is at least slightly smaller than the outside diameter of tubing 11, the latter will be compressed suificiently to cause the flow control member 30 to be eflfectively held in place on the tube by the resiliency or expansivepressure of the tube. Gauge marks may be provided on member30 for indicating the setting thereof; The slotted member 30 is shown in perspective in Figure 4. i

There is also shown in Figure 1'(and in detail in the top plan sectional view of Figure 5) a clamp generally designated 32 and comprising legs 33, 34 pivoted at 35, and joined, adjacent their free ends, by a steel compression spring 36, at least one end of the spring being provided with means for securing and detaching it from one of the legs. As shown, the spring is detachably secured to legs 33 and 34 by hook and eye arrangements. The clamp is disposed between bosses 38, 39 molded integrally with the pump 9 and held in position on the pump by the bosses and is provided with the extensions 33a, 34a which may be held between the fingers for facilitating compression of the spring and,

indirectly, of the pump. The provision of clamp 32, or of any equivalent compressing device, is entirely 0ptional and in most cases is usually dispensed with. However, it may be provided to insure proper compression of the pump 9 when the latter is of such rigidity that it is not readily compressible manually. It may be easier in some cases for a female nurse, for instance, to compress the tube by pressing the legs of the clamp together adjacent their free ends and then releasing the pressure on=the legs to allow the spring to return to its normal expanded state.

'Pump 9 may have any suitable length, has a crosssection greater than the'cross-section of tubing 11, and usually at least twice as great, and preferably has a re- 'siliency and wall thickness such that it is manually compressible to bring the opposite sides of the tubing forming it together or closer together for the purposes set forth below.

When the equipment is set up as shown, and pump 9 is inthe normal expanded condition, the flow of the fluid from bottle 2 being initiated, and balls 25 and 29 being afloat in the fluid in valves 8 and 10, the fluid will flow by gravity from bottle 2 downwardly through the continuous channel formed by the interconnecting hollow or tubular partsto the needle 12 and thence into the vein at a comparatively slow rate controlled by the position of the slotted member 39, and in the form of a""6omparatively'thin stream. However, when pump 9 is compressed, as by grasping itin the handand press= ing the opposite sides of the cylindrical wall together, while the fluid is flowing from the observation housing.

or tube 7, and a constant level of the fluid is maintained in observation housing 7, ball 25 rises into the rearward or lower, slightly outwardly flaring, end of the centrally disposed channel in hollow adaptor 15, which functions as a valve seat, and as soon as the compressing forceis applied the flow of the liquid from the observation tube or housing is cut ofi. When the pressure is removed and the tubular'pump 9 returns to its normal expanded condition, ball 25 is unseated and the system is again open. As a result of the pumping action thus created by compression and expansion ofthe tubular pump, the fluid is forced to flow into the needle at accelerated rate. A series ofalternate compressions and expansions of the compressible pumpwill, therefore, deliver a series of increased doses of the injection fluid into the vein whenever such increased doses are required. i

An outstanding advantage of this novel equipment is that, as will be apparent, it can be used for both normal administration of the fluid by gravity flow andforforced injection of relatively copious amounts thereof at will, without requiring the use of an extraneous air pump in connection with the equipment. That is, it ,is not necessary to force air through the air-way cannula in order 'to increase the quantity .of liquid introduced ,into the'vein. Moreover, the exact'amount of liquid; forced into the vein, as a result of each compression and expansion of pump 9 is determined by the cross-section and length of the pump and the extent to which it is compressed, that is whether the opposite walls are brought more or less closer together by the compressing force exerted thereon. The quantity of fluid forced into the vein by each successive compression of the pump is therefore fixed by the dimensions of the pump and, being once impirically determined for the dimensions of a pump of given cross-section and length, the number of compressions required to force a given totalquantity of fluid into the vein in a given period of time can be predetermined and the equipment can be marketed with exact instructions for the physician or nurse in this respect For example, if pump 9 comprises a tube 5" long and A" in cross-section, each full compres-' ond intervals. The equipment has been used to accomplish the forced intravenous feeding or injection of dlinical dextran which has a viscosity as high as any solution which is apt to be intravenously injected. Actually, it is found that the viscosity of the fluid does not noticeably effect the number of compressions of the pump required to force a given amount of the fluid into the vein and therefore the instructions issued with the equipment are of general application and valid for various types of parenteral injection fluids including glucose solutions, solutions of amino acids and other nutrients,

solutions of antibiotics, such as solutions of penicillin, solutions of liver extract, and other solutions which may be injected safely into the vein.

Pump 9 desirably has a cross-section at least twice the cross-section of tubing 11, the latterusually having a cross-section of to 4,". Pump 9 may have a crosssection of from :5 to 2" and a length of, say, 3" to 6", or it may be even longer than 6".

The equipment shown in Figure 1 may be modified in various ways. As already stated, clamp 32 may be omitted, and if so, the raised portions or bosses on the external wall of 'pump 9 may also be omitted.

In a variation. or modification, when a clamp such as. clamp 32 is provided, it may comprise an adjustable set screw'forlimiting the extent to whichv the spring is compressed so that .a partial compression of the pumpcan be reliably obtained if that, is desired. Also, the check. valves 8 and 1-0; which are. identical and one of which is shown insect-ional detaiLin Figure 3; maybe replaced byother suitable types-ofcheck valve, such as thatshown in- Figure- 6 in which there is shown the tubular. mem-. ber- 40 cemented, at its opposite ends, to the adaptors 41' and 42 ('shown broken away); and enclosing valve member 43 which reciprocates. in the direction of the of the tubing and is provided with a chamfered surface, as'shown at 44, adapted to be seated in the slightly flaring end of the channel in the respective adaptors.

If back-flow due to venous pressure or suction develops in the equipment, the ball 29 will rise and be seated in the channel of adaptor 19, thus interrupting the flow of the liquid until the back-flow is corrected; It will be apparent that, if desired, valve 28 may be omitted.

The new equipment may be used with bottles of types. other than the one shown, which, as marketed, is provided with a seal puncturable by the bottle adaptor aligned with the drip tube 6 and forming an integral part of the equipment. Not all suppliers of intravenous in jcction liquids utilize bottles of that type. Thus, in somejcases, the liquid is put up in a bottle of the screwcap type and without a seal closing the mouth thereofi.

The present equipment may be used with bottles of the last-mentioned type by providing a stopper, such as a rubber stopper, adapted to fit into the mouth of the bottle and provided with channels extending longitudinally thereof and into which, respectively, the bottle adaptor aligned with the drip tube 6, and the air-way cannula and shield therefor may be inserted. Such an arrangement is shown in Figure 7', in which bottle 45 of screwcap type (shown broken away) is provided with a rubber stopper or gasket 46 having channels forreceiving the bottle adaptor 47 and the air-way cannula and shield or air-way tube designated as 47a. The stopper may have any desired diameter, depending on the diameter of the bottle mouth, and may be marketed separately from the equipment or in assembly therewith, e.g., pressfitted on the bottle adaptor. It may be, and preferably is, marketed as a separate item but with the shield for the air-way cannula inserted therein so that, in assembling the equipment, it is unnecessary for the nurse or doctor to touch the shield which, in use, extends through the injection liquid. Stoppers of 'the kind shaped in a mold adapted to leave a thin layer of the rubber in the form of a readily puncturable diaphragm over the ends of the channels which serve as the inlet ends when the device is in use are preferably employed, the bottle adaptor and air-way cannula. being pushed through the diaphragms into position in the stopper.

As shown in Figure 8, the drip tube 48 may be branched, as. at 49 and 50, each of the branches being adapted to project into a bottle or container and receive a diiferent injection fluid from it. As shown, the bottles 51, 52 are tilted so that the. fluid from each flows smoothly into the drip tube.

In Figures 9 and there is shown a modified pump and valve arrangement in which the check valves 53, 54 are, at least in effect, integral parts of the compressible tubular pump 55, and connected withthe remaining elements of the equipment through adaptors 56, 57, respectively, and suitable couplings.

The balls 58' 311(1159 are inserted in the valves 53, 54,

respectively, the latter are fitted into the opposite ends' of the tubular pump 55, and may be cemented to the pump.

Inresponse to lateral compression of tube 55, the balls 58 and 59" of the valves function in the same manner as the balls 25, 29' of the equipment of Figure. l, but are restrained in their downward movement by the disk- like members 60, 61 press-fitted'in the flanges (indicated. by, n m r l 62 i1'63. e p c ly). on. he inn r; all of; tubeSfS. The disk- like members 60,61 may beoffa type such that they alsoserve, as filters for the liquid; The restraining. disks, 6Q 61; (one of which, 60, is shown in the sectional top plan view of Figure 10); may beformed l of surgical rubber or suitable plastic material such as nylon, Dacronfi polystyrene or theliker Suitable filtersmay be provided at appropriate places. As previously mentioned, the re.-' straining. members injthe. valves of Figures 1 and. 3., and

in the equipment.

the. disksofi'FigureS 9. and 10 may be of types. that serve.

the additional. purpose of filtering theliquid, The reel straining members or disks may be of fibrous character and formed, for example, of cotton, nylon, regenerated cellulose and the like. They may be formed from woven fabrics comprising spun yarns arranged so that the ends.

of. the short. or staple fibers projecting from the spun yarnsinter-mesh to form sinuous channels which mean-.

normal gravity flow, and for the forced administration. of the fluid rapidly and incontrolled amounts in a. given.

period of; time as. may be required without requiring; the use. .of an extraneous airpump.

conventional equipment. Itcan be effectively evacuated by means. of the pump before theneedle is injected, the air which is. forced'upwardly in the direction ofthe bottle leaving the latter through the air-way cannula.

Once the liquid is flowing in the device and has passedthe first check valve, a partial vacuum exists in the.

system and it is. impossible for air to. become entrained.

inv the liquid. Since the. pressure of the air on. the.

liquid and the venous. pressure are in equilibrium, and; any disturbance thereof is immediately corrected by the;

action of. the second. valve, the danger of accidentally injecting air into the vein, and of resulting air embolus,

is entirely eliminated. It also. eliminates the danger.

of introducing air-borne. contaminants into the vein and.

will assist in preventing the incidence of hepatitis when; plasma isinjected. Other advantages are that the pump, valves, and other parts constitute a single unit for the.-

combined purposes of normal and forced injection or;

feeding, no accessory equipment or devices such as aseparate, portable air pump being needed, the unitis,

disposable, therate of transfusion is clearly visible along: the entire. length of the preferred embodiment of; the, equipment, the latter is compact and may be packaged separately or as a unit with the injection fluid, it is;

relatively light in weight and easily transportable, it may be packed sterile, for instance as av standard item of the physicians. or ambulance kit, it can be put into;

use quickly under emergency conditions, as in time. of

war, without technical difiiculties, none of the. parts is breakable when, as is preferred, the essential elements of the equipment are made of tough plastic; material, reverse flow or back-pressure is eliminated, and. if the needle is-obstructed, as by a venous clot, the obstruction can be immediately dislodged by a slight compression of the pump, just suflicient to increase the fluid flow and-dislodge the obstruction.

Although it is preferred toform all of the essential parts of the equipment" of clear, transparent and tough plastic, certain parts thereof, such as the drip. tube and observation housing, may be made of, glass, if desired.

In addition; the; equipment entirely lacks the major disadvantages. ofthe It will be understood, ofcours eQthatthe relative proportionsof the check ValVe orLt he and the end of the channels in the respective adaptors which serve to seat the balls is such that the valve is seated promptly to close oi the supply of fluid immediately on compression of the pump, or to relieve back-flow as soon as it develops. The check ball should be light inweight and responsive to the pressure of the fluid. Further, the tubular members comprising the valves are preferably smaller in cross-section than the-pump and relatively short as compared to the pump and the check ball is also small, the channels in the adaptors in which the balls are seated being flared outwardly to the degree necessary to permit ready closing of the channel, at the mouth thereof, by the balls when the latter are moved into the mouth of the channels as a result of compression of the pump or by back pressure tending to induce back-flow in the equipment. It will be understood that the pump may have diiferent shapes and may be, for example, a ball-type pump.

Since all of these various modifications in details may be made without departing from the scope of this disclosure, or of the invention, it is to be understood that it is not intended to limit the invention except as defined in the appended claims.

I claim:

1. Venoclysis equipment formed of plastic material substantially all of which is transparent and adapted normally to provide a continuous channel for injecting a fluid flowing from a source of supply to a hypodermic cannula, said equipment comprising in combination a drip tube, a housing for the drip tube, and a length of tubing of relatively small cross section adapted to receive the cannula at one end thereof and including disposed along its length below the drip tube and above the end of the tubing of relatively small cross section removed from the cannula receiving end, and as, at least in effect, an integral part of the equipment, a tubular pump compressible transversely of the axis of the equipment and readily returnable to normally expanded condition and release of the compressing force, said equipment including a valve element and a valve seat element for said valve element operable to close the inlet into the pump when the pump is compressed.

2. Venoclysis equipment formed of transparent plastic material and adapted normally to provide a continuous channel for injection fluid flowing from a source of supply to a hypodermic cannula, said equipment comprising, in combination, a drip tube, a housing for the drip tube, and a length of tubing of relatively small cross-section adapted to receive the cannula at one end thereof, and including, disposed along its length, between the housing for the drip tube and the end of the tubing of relatively small cross-section removed from the cannula-receiving end, and as, at least in effect, an integral part of the equipment, a pump and check valve system, the pump being tubular, compressible transversely of the axis of the equipment and readily returnable to normal expanded condition on release of the compressing force.

3. Venoclysis equipment in accordance with claim 2, characterized in that the drip tube and the observation tube are formed of relatively rigid plastic material and the pump and cannula-supporting tubing are formed of more flexible and resilient plastic material.

4. Venoclysis equipment formed of transparent plastic material and adapted normally to provide a continuous channel for injection fluid flowing from a source of supply to a hypodermic cannula, the equipment comprising, in combination, a drip tube, a housing for the drip tube, and a length of tubing of relatively small cross-section adapted to receive the cannula at one end thereof, and including, disposed along itslength, between the housing for the drip tube and the end of the tubing of. relatively small vcroiss-sectio ernd u cannula receiving end, and as, at least in eflec gral part of the equipment, a pump and check valve system, the pump being formed of plasticized polyvinyl chloride, and being compressible transversely ofrthe axis of the equipment and readily returnable, to normal expanded condition on release of the compressing force.

' 5. Venoclysis equipment formed of transparent'plastic material and adapted normally to provide a continuous channel for injection fluidflowing from a source of supply to a hypodermic cannula, the equipment comprising, in combination,'a driptube, a housing forth'e drip tube, and a length of tubing of relatively small cross-section adapted to receive the cannulaat one end thereof and including, disposed along its length, between the housing for the drip tube and the end of the tubing of relatively small cross-section removed from the cannula-receiving end, and as, at least in effect, an integral part of the equipment, a pump and check valve system, the pump being a tubular member of predetermined length and cross-section, compressible transversely of the axis of the equipment, and readily returnable to normal expanded condition on release of the compressing force.

6. Venoclysis equipment according to claim 5 char- .acterized in that the predetermined cross-section of the of the observation tube, a tubular pump of relatively large cross-section and having an inlet and an outlet, the inlet being connected with the outlet of the check valve, a second check valve having an inlet and an outlet, the inlet being connected with the outlet of the pump, and a length of tubing of relatively small crosssection and one end of which is connected with the outlet of the second check valve and the other end of which is adapted to receive the cannula, said tubular pump being compressible transversely of the axis of the equipment and readily returnable to normal expanded condition on release of the compressing force.

8. Venoclysis equipment adapted normally to provide a continuous channel for injection fluid flowing from a source of supply to a hypodermic cannula and comprising a drip tube, an observation tube enclosing the drip tube and open at the bottom, a check valve having an inlet and an outlet, the inlet being connected with the bottom of the observation tube, a tubular pump of relatively large cross-section and having an inlet and an outlet, the inlet being connected with the outlet of the check valve, and a length of tubing of relatively small cross-section and one end of which is connected with the outlet of the tubular pump and the other end of which is adapted to receive the cannula, said tubular pump being compressible transversely of the axis of the equipment and readily returnable to normal expanded condition on release of the compressing force.

9. Venocylsis equipment adapted normally to provide a continuous channel for injection fluid flowing from asource of supply to a hypodermic cannula and comprising a drip tube, an observation tube enclosing the drip tube and open at the bottom, a tubular member of relatively large cross-section and having a check valve forming an integral part thereof at each of its opposite ends, the forward check valve having an inlet connected to the bottom of the observation tube and the rearward check valve having an outlet connected to a length of tubing of relatively small cross-section and adapted to receive the cannula on the free end thereof, said tubular member having the check valves directly associated therewith consitituting a pump Compressible transversely of the (if the'equipment and readily returnable to, normalj'expanded 'cqndition on release of the compressing to e.

Tenney Nov. 21, 19 16. Brokaw Feb. 13', 191 7 Heir Sept. 15, I925 Ravenscroft, et-ral Sept. 10, 1940;.

- 12 Sehwab V Apr. 22, 1941 Abbgtt" Jan. 16,- 1951 Cutter July-7; 1953;} Butler Mar. 16; 1954 Dennis Y Apr. 6; 1954' Ryaniet a1; June-22; 1954;

OTHER REFERENCES I Fischer et al.: Successful Experimental Maintenance: 10 of,Life; Annals of Surgery,,ve 1.. 136, No. 3, September 1952, pages 415-484., page 478. relied on, in- Scienee Library.)

(Available, 4

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