US3052238A - Pressure flow device - Google Patents

Description

P 1962 c. R. BROMAN ETAL 3,052,238

PRESSURE FLOW DEVICE Filed April 22, 1958 ///I A/AN ATTORNEYS.

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3,052,238 Patented Sept. 4, 1962 ice 3,052,238 PRESSURE FLOW DEVICE Cyrus R. Broman, Evanston, and Karl E. Baumann, Mount Prospect, 111., assignors to Baxter Laboratories, Inc, Morton Grove, 111., a corporation of Delaware Filed Apr. 22, 1958, Ser. No. 730,123 2 Claims. (Cl. 128--214} This invention relates to a pressure fiow device, and, more particularly, to a pressure flow device for blood, as in transfusion, and the like.

In the flow of blood external to the body, it is often necessary to accelerate the flow. For example, in the administration of blood during surgery, after an accident, etc., it is often desirable to administer previously collected blood at faster rates than gravity flow permits. For a considerable period, surgeons have been employing manually-operable blood pumps for this purpose which operate on the squeeze bulb principle. An example of a manually-operable blood pump can be seen in the copending application of Cyrus R. Broman, Serial No. 428,739, filed May 10, 1954, and reference is hereby made to that application.

It is also desirable to accelerate blood flow external to the body in instances where a patients blood is being circulated through a blood rehabilitating device such as an artificial heart-lung or an artificial kidney. In all of these instances, the device-s heretofore employed have been characterized by a number of disadvantages.

One significant disadvantage is the damage inflicted on the red blood cells by the previously employed pumping devices. These devices permitted quick application of pressure to blood confined in a conduit and therefore subjected the cells to shock. Another disadvantage is that the pumping devices heretofore utilized do not provide an easily measurable, uniform pumping action on the blood, so that the administrator can carefully regulate the rate at which blood is being circulated.

It is an object of this invention to provide a novel pressure flow device for blood, and the like, which overcomes the disadvantages outlined above. Another object is to provide a novel pumping structure for fluid flowing within a resilient conduit. Still another object is to provide a novel means for cyclically varying the pressure on a resilient conduit carrying a fluid. Yet another object is to provide a novel pressure flow device which includes a chamber about a resilient flow conduit with means for cyclically varying the pressure within the chamber.

A further object is to provide a novel pumping device for fluid flowing in a resilient conduit which includes an expansible chamber about the conduit, cyclically pressurized by a prime mover free of electrical power. A still further object is to provide a novel pumping device for fluids flowing in a resilient conduit which includes a plurality of chambers about the conduits, the chambers being cyclically pressurized. Other objects and advantages, both general and specific, can be seen as this specification proceeds.

This invention will be described in conjunction with the accompanying drawings, in which FIG. 1 is an elevational view of aparenteral administration system incorporating features of this invention; FIG. 2 is an enlarged elevational view of the expansible chambers utilized in the practice of one form of the invention; and FIG. 3 is a fragmentary elevational view of a blood circulating system including an artificial heart-lung.

Referring now to the drawing, the number designates a parenteral solution bottle containing saline as is designated by the numeral 11. The numeral 12 designates a similar bottle but which is filled with blood as designated by the numeral 13. Both bottles 10 and 12 are equipped with bands 14 and bails 15 which are employed for suspending the bottles in a mouth-downward condition. Each bottle is equipped with a closure 16, equipped with a flow passage (not shown), through which the liquid contained in the bottle is able to flow by gravity into an administration set designated generally by the numeral 17. As liquid flows out of bottles 10* and 12, the space formerly occupied by the liquid is filled with air entering through a second flow passage in closures 16 and which communicates with an air tube 18.

The administration set 17 is a Y type set having inlet connections 18 and 19 communicating with bottles 10 and 12, respectively. Connections 18 and 19 are united above a drip housing 20 and communicate therewith. The lower portion of housing 20 communicates with a length of flexible tubing 21, which is provided at its lower end with an adapter 22 to which a hypodermic needle can be fixed. Each of the connections 18 and 19 is equipped with a clamp 23 to regulate the flow of fluid therethrough.

In the use of the apparatus just described, clamp 23 on connection 18 is first opened to permit filling the set with saline. A small amount of air is allowed to remain in drip housing 20 above filter 24 and below and around the dropforming tube 25 thereof. Adapter 22 is equipped with a hypodermic needle or cannula (not shown) and introduced under the skin of an intended recipient. Flashback indicating device 26 is then squeezed and released. If the cannula is properly positioned within a vein of the intended recipient, blood will be aspirated back into the set and will produce a red coloration visible through the translucent adapter which is filled with colorless saline.

The administration of saline is then discontinued by closing clamp 23 in connection 18 and the administration of blood is started by the opening of clamp 23 on connection 19. At the end of the transfusion, i.e., when bottle 12 is depleted of blood, clamp 23 of connection 19 is then closed and clamp 23 of connection 18 is opened, whereupon saline is once again administered. This insures that virtually all the blood of bottle 12 is administered.

During the course of an administration of blood, it is sometimes necessary to administer 'blood at more rapid rates. For this purpose, the drip housing 20 is constructed of a resilient material so that the housing 20 can be compressed transversely of its axis. This feature, along with a check valve in the form of a floating ball 27, adapted to coact with the drop-forming tube 25, permits a pumping action on blood within drip housing 20. This feature is described in greater detail in the above-mentioned Broman application. Heretofore, the pumping on drip housing 20 has been performed manually, as by the anesthetist, who constantly watches the gauges which indicate the blood pressure of the patient receiving blood. The manual squeezing of the drip housing 20 results in shocks to the blood which may damage the red cells. In

" addition, where large quantities of blood are needed rapidly, it is virtually impossible to make sure that any given quantity of blood is administered in a given time, since this will be a function of the degree to which the drip housing 20 is compressed.

We overcome these disadvantages by providing drip housing 20 with a chamber 28 thereabout which may take the form of an annular sleeve constructed of a heatscalable thermoplastic material in which the upper and lower edges of the sleeve are united as at 29 and 30 to the drip housing 20. A port 31 is provided in chamber 28 which leads to a pressure switching device generally designated 32.

The construction of chamber 28 can be seen also in FIG. 2, in which a pair of chambers 128 are provided on a conduit 120. Each chamber is equipped with a port 131 which may be connected to pressure switching devices. Ey employing two such chambers 128, the need for the check valve structure including ball 27 and drip tube 25 is eliminated. By using the left-hand chamber 128 as a flow checking means, the internal pressuring of the right-hand chamber 128 causes any fluid within conduit 120 to be forcedto the right in the illustration given in FIG. 2. It may be desirable in some instances to construct the outer wall of chamber 128 of a material substantially stiifer than conduit 120 so that the pressure of a fluid within chamber 128 preferentially causes the collapse of conduit 120. Alternatively, it is possible to provide chamber 128 separate from conduit 120 as by making chamber 128 C-shaped in cross section, with the outer wall being more rigid than the inner wall. However, we prefer to provide the chamber integral with housing 20, since this eliminates any possible damage to the filter 24 and the valve structure including drip tube 25 and ball 27 through mispositioning of the chamber.

The pressure switching means 32 which cyclically internally pressurizes chamber 128 may utilize any pressure fluid. Excellent results have been obtained with compressed air. The pressure switching device 32 which uses such a pressure fluid is seen to include a casing 33 having a chamber 34 therein which serves as the cylindrical casing for a freely-mounted piston 35 The ends of the chamber 34 are closed as at 36 and 37 by suitable covers which are apertured as at 36a and 37a to receive pipes 36b and 37b which terminate in poppet valves 36c and 370. Through actuation of poppet valves 36c and 370, it is possible to vent either end of chamber 34 to the atmosphere. When either end is so vented, and the other end pressurized, pistons 35 will shift in position. A pressurized fluid is introduced into chamber 34 through inlet 38 and fiows about an annular space between piston 35 an-dcasing 33 such as is designated by the numeral 39. Pressurized fluid within the annular space 39 flows into a subchamber 4-0 and thence through a transverse bore 41 within piston 35. Piston 35 is also equipped with constricted longitudinal bores as at 42 and 43 which permit the flow of pressurized fluid into the end portions of chamber 3-4. The annular space 39 is sealed from the end portions of chamber 34 by suitable annular seals such as are designated by the numeral 44.

Piston 35 carries a slide valve element 45 which is loosely mounted in the transverse bore 41, the slide valve 45 shifting position in subchamber 40 corresponding to the shifting of piston 35 in chamber 34. The bottom portion of snbchamber 40 is closed by a subcasing 46 which is equipped with three flow passages. One flow passage 47 is an exhaust passage, as to the atmosphere in the case compressed air is used as the pressure fluid. The other two flow passages in casing 46 are connected to opposite ends of a pressure cylinder 48. For example, flow passage 49 is in communication with the right-hand end of cylinder 48 by means of piping 50, while the righthand flow passage 51 is in communication with the lefthand end of cylinder 48 by means of piping 52. Cylinder 48 has reciprocably mounted therein a piston 53 which is equipped with extension rods 54 and 55 extending axially outward of cylinder 48 and equipped with poppet valveactuating collars 54a and 55a, respectively. A more comprehensive description of the piston-actuated valve can be seen in Lieser Patent No. 2,792,019, issued May 14, 1957.

'In the operation of the apparatus shown in FIG. 1, coll ar 54a has just opened poppet valve 360 which vents the right-hand end of chamber 34. Since the left-hand end of chamber 34 is at a higher pressure, poppet valve 370 being closed, piston 35 travels to the right. This produces a corresponding movement in slide valve 45 which will couple flow passage 51 with exhaust passage 47, permitting the left-hand end of cylinder 48 to be vented through line 52. The shift to the right of slide valve 45 communicates flow passage 49 with the pressurized subchamber 40 and applies pressure to the right-hand end of cylinder 48 and to chamber 28, the latter causing collapse of drip housing 20. The piston 53 of cylinder 43 moves to the left because of the pressure differential at the two ends thereof and until collar 55a actuates poppet valve 370. This results in reshifting of piston 35 back to the position shown in FIG. 1, in which chamber 28 is coupled through pipe 50 to exhaust passage 47.

It can, therefore, be seen that each shift of piston 35 to the right internally pressurizes chamber 28, while each shift to the left results in venting chamber 28 to the atmosphere. The use of the fluid-actuated pressure switching means 32 provides for the cyclic pressurizing of chamber 28 without the need of using any kind of electrical switching apparatus. In many operations, it is undesirable to have any electrical equipment in the operating room, since arcing in such equipment has, on occasion, resulted in explosions. Excellent results have been obtained through merely venting chamber 23 to the atmosphere through exhaust passage 47. The resiliency of drip housing 20 causes the housing to return to its cylindrical shape. However, a more positive return to shape can be achieved through alternately coupling the port 31 to a vacuum pump, or the like. For example, this could be done by coupling passage 47 to a source of vacuum.

In the illustration given, the chamber 28 is completely exterior to housing 20, so that the compressed air used has no chance of entering the flow line. However, should a particular installation require complete absence of compressed air or other gas, a pressurized liquid can be used in place of the compressed air for cyclically internally pres-surizing chamber 28. Using saline, for example, as the pressure fluid, makes any leak in the housing 26 of no consequence in so far as introducing foreign material into the blood. Also, with a rigid outer wall in chamber 28, the amount of blood pumped would then be equal to the amount of liquid introduced thereinto.

Another environment in which the invention can be advantageously employed is depicted in FIG. 3. There, a flow conduit 22!) is shown equipped with three chambers designated 228a, 228b and 22-80, arranged in tandem or series relation about condut 220. Conduit 220 at one end is connected to an artificial heat-lung generally designated by the numeral 256 and which is employed to oxygenate blood during the period in which a patients heart is stopped, as, for example, during heart surgery. The conduit 220 brings carbon dioxide-carrying blood from a major vein source such as the vena cava. This is pumped through the operation of chambers 228a-c into a vertitically-extending oxygenating chamber 257. Simultaneously, oxygen is bubbled upwardly through oxygenating chamber 257 from oxygen supply line 258. The upper end of oxygenating chamber 257 communicates with a generally transversely oriented de-foaming chamber 259 which is vented to the atmosphere as at 260. De-foarm'ng of the oxygenating blood is achieved by passing the blood through a plurality of screens 261 which are disposed one within the other and supported at one end as at 262 while being closed at the other end. De-foamed blood from chamber 259 then flows downwardly along an inclined path provided by channel 263 and is finally received by a return conduit 264 which is coupled to a major artery in the body of the patient. The artificial heart-lung 256 may be constructed of two sheets of thermoplastic material heat-sealed along three sides thereof as at 265, 266 and 267. A hanger strap 268 can be conveniently heatsealed at the ends thereof to the ends of the top side 266 to provide mounting means for the unit 256. The sheets are additionally heat-sealed together along a line 269 to define the oxygenating chamber 257 and along a transverse line as at 270 to partially define the de-foaming chamber 259. Still further, union-s between the two sheets can be provided as at 271 and 272 to provide the inclined flow passage 263. Likewise, the screens 261 can be integrated into the union by heat-seals at the secured ends 262.

To circulate blood through conduit 220 from the patient to the unit 256, the conduit 220 can be first filled with blood either by gravity flow from the patient or by priming from a suitable external source. Thereafter, chamber 228a is internally pressurized to inwardly collapse the walls of conduit 220 within chamber 228a. This action serves to prevent further flow of blood through conduit 220 and, in effect, is a check valve action. Thereafter, chamber 22% is internally pressurized to pump blood into unit 256. After the internal pressurizing of chamber 228b, chamber 2230 is internally pressurized to pump additional blood into unit 256. Thereafter, and while chamber 228s is internally pressurized, chambers 22 8a and 2225b are depressurized and the conduit 22!) comprehended within the lengths of these two chambers is refilled with blood. As pointed out above, this can be either achieved merely by venting chambers 228a and 228b, in which case the inherent resiliency of conduit 220 will bring blood into the portions of conduit 220 covered by chambers 228a and 228b, or these two chambers can be connected to a vacuum line. Thereafter, chamber 228c is de-pressurized, and chamber 228a is pressurized to recommence another pumping cycle. Thus, in effect, chambers 228a and 2280 operate as check valves with chamber 223s being closed primarily when chamber 228b is being filled, and chamber 223a is closed primarily when chamber 22 8b is being emptied. Excellent results have been obtained when chambers 228a and 2280 are substantially smaller in volume than chamber 22%. By making the chambers substantially smaller, undesirable back-flow is substantially minimized. This is desirable in the event a second plurality of chambers such as 228a-c are employed in connection with the return line 264.

Chamber 223]) extends over a substantially greater portion of conduit 220 than do chambers 228a and 2280. The collapse of the interior walls of these last-mentioned chambers, therefore, causes little or no shifting of fluid within conduit 220, While the pressurizing of chamber 22% does result in movement of a substantial volume of fluid. This movement is initiated gradually so that no hemolysis-producing shocks are applied to blood in conduit 220.

I11 addition to eliminating undesirable hemolysis due to the harsh application of pumping pressures to a resilient conduit, the structure herein provides for easily and accurately determining the volume of blood pumped. No matter Whether the volume in the pumping chamber is forced out slowly or rapidly, the same volume will be expelled each stroke, so that the total volume pumped is determined merely by counting the number of strokes per minute. Here, it is to be appreciated that the application of fluid pressure to the collapsible walls of the pumping chamber provides a cushioning effect that avoids the undesirable hemolysis which occurred in previouslyemployed structures. The structure herein presented is also versatile in that merely by adjusting the fluid pressure entering port 31, the device can be made to pump either constant volumes or at constant pressure. By adjusting the pressure applied to the collapsible walls of the chamber to less than that necessary to completely bring them together, a non-occlusive pump is provided which forces the pumped liquid along the conduit at a ponstant pressure for each stroke. In other instances,

it may be desirable to have an occlusive-type pump, wherein specific volumes are delivered irrespective of the pressures encountered. Either type can be provided with equal facility in our invention.

While, in the foregoing specification, a detailed description has been given for the purpose of understanding, it will be understood that the details thereof may be varied considerably by those skilled in the art without departing from the spirit and scope of the invention.

We claim:

1. A blood administration set adapted to provide a continuous channel for blood flowing from a source to an injection needle, comprising a drip tube, a housing for the drip tube, and connected to said housing a length of tubing of relatively small cross-section adapted to receive the needle at one end thereof and, disposed along the length of said tubing as an integral part thereof, a pump and check valve system for optionally increasing the flow of blood to said needle, said pump including a resilient pumping chamber with chamber means about said pumping chamber, and means for cyclically pressurizing the interior of said chamber means said pressurizing means being pneumatically operated and free of any electrical power.

2. A blood administration set formed of transparent plastic material and adapted normally to provide a continuous channel for blood flowing from a source of supply to a hypodermic needle, the set comprising, in combination, a drip tube, a housing for the drip tube, and connected to said housing a length of relatively small crosssection tubing adapted to receive the needle 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 needlereceiving end and as an integral part of the set, a pump and check valve system, the pump being tubular, com pressible transversely of the axis of the set and readily returnable to normal expanded condition on release of the compressing force, an annular chamber about said pump, said chamber communicating with a source of pressurized fluid, and means for alternately flowing pressurized fluid to and from said chamber.

References Cited in the file of this patent UNITED STATES PATENTS 2,291,912 Meyers Aug. 4, 1942 2,812,716 Gray Nov. 12, 1957 2,879,784 Cutter Mar. 31, 1959 2,927,582 Berkman et a1. Mar. 8, 1960 FOREIGN PATENTS 874,199 Germany Apr. 20, 1953 OTHER REFERENCES Fischer et a1.: Experimental Maintenance of Life, Annals of Surgery, volume 136, No. 3, September 1952, p. 478 relied on.

Clowes et a1.: Pump Oxygenator, Surgery, volume 36, No. 3, September 1954, p. 562 relied on. (Available in Scientific Library.) l i A

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