US3901231A - Infusion pump apparatus - Google Patents

Abstract

Infusion pump apparatus for delivering intravenous fluid from a syringe to a patient so that volume may be accurately controlled between a small delivery rate and a large delivery rate is disclosed. The pump is adaptable to adjust the amplitude of the syringe stroke in order to accurately meter the volume of fluid delivered to a patient within a given time period. The pump may be employed in an oxygen atmosphere without creating a potentially dangerous condition likely to result in an explosion. An an optional feature a pressure sensitive arrangement which stops the pump in the event the resistance to flow of fluid becomes greater than that required for normal operation is also disclosed.

Description

[11] 3,901,231 Aug. 26, 1975 INFUSION PUMP APPARATUS [75] Inventor: Raymond 6. Olson, Niles, 111.

[73] Assignee: Baxter Laboratories, Inc., Morton Grove, Ill.

[22] Filed: Feb. 7, 1974 [21] Appl. No.-:440,4l0

[52] US. Cl. 128/214 F; 128/218 R; 92/13]; l28/D1G, 1; 128/010. 12; 128/D1G. 13

[51] Int. Cl. A6lm 5/00 [58] Fieldoiseal'clt 128/214 E,2l4 F,218 A, 128/218 R, 218 G, DIG. l, DIG. l2, DIG. 13;

5/1973 Wilhclmson ct a1 l28/D1G. l 6/1974 Fumagalli 92/l3.7

Primary Examiner-Richard A. Gaudet Assistant Examiner-Henry S. Layton [57] ABSTRACT Infusion pump apparatus for delivering intravenous fluid from a syringe to a patient so that volume may be accurately controlled between a small delivery rate and a large delivery rate is disclosed. The pump is adaptable to adjust the amplitude of the syringe stroke in order to accurately meter the volume of fluid delivered to a patient within a given time period. The pump may be employed in an oxygen atmosphere without creating a potentially dangerous condition likely to result in an explosion. An an optional feature a pressure sensitive arrangement which stops the pump in the event the resistance to flow of fluid becomes greater than that required for normal operation is also disclosed.

5 Claims, 7 Drawing Figures PATENTEU Auszs 197s SHIT 1BF 4 PATIENT PATENTEBAUBZSIQTS" 3.9019231 T0 i T0 PATIENT PATIENT l V SOLUTION mrusrou PUMP APPARATUS The present invention relates to an infusion pump system and more particularly to a pump having a synchronous motor adaptable to move a piston of a surgical syringe to deliver to a patient predetermined accurately measured volumetric amounts of intravenous fluid.

The use of surgical syringes for injecting intravenous fluid into the veins of a pateint has long been known. It is common practice to employ a syringe comprising a cylinder and a piston reciprocatingly disposed therein to cause fluid to 'move from a source of supply to a patient who requires a constant and measured amount of the fluid for purposes of life sustaining nourishment or other aspects of medicinal treatment.

Various means may be utilized to operate the piston of a syringe. The most elementary means for causing movement of a piston would be pressing by hand against a rod portion of the piston extending exteriorly of the cylinder, thereby forcing the head of the piston to move rectilinearly and pump fluid from the supply source to the patient. Modern technology has developed more advanced and sophisticated means for delivering fluid from a source of supply by means of a syringe. In this connection, electromechanical devices have been created that automatically move a piston or plunger of a syringe to cause fluid to be pumped to a patient who requires the adminstering of intravenous fluid to obtain nutrients for sustaining life.

Illustrative of devices that may be used to pump intravenous fluid is a so called syringe pump that comprises a pump assembly adaptable to be either permanently affixed to a syringe or detachably connected thereto. A detachable syringe pump assembly is shown by Rosenberg in US. Pat. No. 3,447,479. However Rosenberg discloses a pump driven by the combined efforts of a synchronous timing motor and an induction drive motor.

There are inherent problems to be overcome combining operating characteristics of such drive motors; Among the problems encountered by induction motors are the continual making and breaking of electrical. contact with resultant arcing between contacts, the dis-; advantages of which are self-evident when one is re-. quired to operate a motor in an atmosphere wherein: free oxygen is present. Moreover, induction type mo-- tors are affected by variances in voltage and thus it isdifficult if not impossible to deliver with exactitude a: constant and closely controlled volume of intravenous" fluid wherein the power services may be irregular; thus,; the supply of energy to the pump may vary greatly with? resultant highly diverse amounts of fluid pumped into a patients veins.

BRIEF SUMMARY OF THE INVENTION In accordance with a major feature of the present irivention infusion pump apparatus is provided for rectilinear pumping and delivery of fluid, e.g., l.V. solution to a patient, at an average rate which can be selected within a range of rates. The apparatus includes a novel rate selecting mechanism which includes means for defining an arcuate movement path and means for pivotally reciprocating the arcuate means. A driving linkage is coupled to reciprocate the pump and also coupled to be moved by the arcuate means while reciprocating along a range of positions on the arcuate path thereon.

A range of defining member is coupled to the driving linkage for movement therewith and has a fixed pivot whose position is selectively variable. At any fixed pivot point the member limits the range of movement of the driving member along the arcuate path and thus fixes the stroke and average output of the pump.

In accordance with another feature of the invention means are provided for sensing the pressure in fluid output and for stopping the pump or signaling a warning for sensed pressures over a preselected high value.

This latter feature has the advantage of preventing damage to the patient should the l.V. capillary be inserted wrongly, e.g. into a muscle tissue.

These and other features and advantages of the invention will become apparent from the ensuing description, reference being had to the accompanying drawings, in which like members are used to identify like elements in the several views.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a portable stand adaptable to support a source of supply of intravenous fluid, infusion pump apparatus including a syringe pump and a motor drive assembly therefor.

FIG. 2 is a perspective view of the syringe pump and drive assembly showing more specific details of its exterior construction.

FIG. 3 is a vertical front sectional view through the pump and drive assembly with the front portion of the housing broken away so that the working parts of the drive assembly may be seen more clearly. The component parts of the assembly are shown in two positions, the solid lines showing the syringe piston fully extended, the dotted lines showing the syringe piston fully retracted, and defining a maximum amplitude of syringe stroke.

FIG. 4 is a vertical front sectional view of the pump and drive assembly similar to FIG. 3 but showing the component parts operative between a position of complete piston extension and complete piston retraction, but defining an intermediate amplitude of syringe stroke. 1

FIG. 5 is a vertical side sectional view through the drive assembly, taken along line 55 of FIG. 3, a front portion of the housing broken away to show more clearly the working parts thereof. The drive assembly is shown secured to a portion of a vertical column of the stand.

FIG. 6 is a schematic diagram of a control circuit for use with the subject pump system.

FIG. 7 is a schematic diagram of a control circuit similar to that shown in FIG. 6 employing a pressure sensitive device for use with the subject pump system.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, an'infusionpump apparatus 10 is shown mounted by a clamping arrangement on avertical rod member 12 of aportable stand 14 adaptable to support an intravenousfluid storage bottle 16 from ahook member 18 disposed at an upper end of therod member 12.

As seen more clearly in FIG. 2pump apparatus 10 comprises ahousing 20 having afront face member 22,side members 24,top 26 andbottom 28 members and aback plate 30.Front face member 22 may be remov ably secured to housing 20 as bymachine screws 32.

Access to the interior of the housing is accomplished by unthreading the screws and removingface member 22 from the housing. I

Face member 22 has imprinted thereon ascale 34 of incremental numbcrs corresponding to a desired .parametcr of operation for pumping of fluid by the appa; ratus. As illustrated. the-scale 34 shows a range of numbers from to 300 and refers to milliliters of fluid pumped per hour. Adjustingknob 36 is keyed in a known manner to an exterior portionof ashaft 38 FIG. 5) hereinafter described in detail disposed within the housing. rotation of theknob 36 serves to set the pump at a predetermined rate of delivery of fluid for infusion into the veins of a patient and the volume of fluid flow is indicated by afingcr 39 formed integrally withand extending outwardly fromknob 36. Adjustingknob 36 must include a friction loaded shaft provision or other means (such as a lock knob) to insure that it will main tain itself in any desired selected position to have the apparatus pump the required flow of fluid. The friction shaft or other provisions are needed to overcome a small tendency of the hereinafter described variable rate mechanism to shift the setting.

Aknurled member 42 is located exteriorly of theface 22 and iskeyed to a portion of a shaft 44 (FIG. 5) extensive exteriorly of the housing. Theknurled member 44 is effective when rotated to move amagnetic switch 46 assembly (FIGS. 3 and 4) between off and on positions to activate the pump apparatus. Although the switch is preferably of the type shown, the present invention, at least in its broader aspects, contemplates the use of alternative switches such as the conventional toggle switch.

An operation or onlight 150 is disposed -inface member 22 and serves to indicate that the apparatus flange62 formed thereon adapted to be securablyand pivotally received by ayoke 64 carved from an exterior end ofa lever member 66 (hereinafter described in detail). The rod member has an inner end formed toprovide a piston (not shown) head or plunger adaptable to move reciprocat'ingly within thebody 56 of thesyringe 58. i

The upper end ofsyringe 58 is operatively con n ected. as is well known in the art to a valve arrangement68. (FIGS. 1 and 2) that permits flow offluid therethrough ofsyringe 58 isa" rodmember 60 having a circular only to the patient and prevents back flow of solution into thebottle 16 when rod member moves upwardly to cause pressure to be exerted invalve arrangement 68. This is preferably a pair of one-way valves permitting flow only fromI.V. bottle 16 tosyringe 58 and from syringe S8 to the patient-connected line.

Referringnow to FIGS. 3, 4, and 5, it can be seen that of pivot ll2P byfixing the stroke pair ofarcuate.grooves 82..Ihefifstleg-7:8A= has itsend 84 pivotally connected at 86 to the mountingplate 72.

A firstlink driving mcmber 90 has a first end 92 'pivotally secured substantially intermediate "the ends oflever 66 and has a second end,94 secured asbypins 96 received in thearcuate grooves 82 of membcr=78. It should be noted that thesecond end 94 oflink 90 may be assumed positions along an arcuate path defined by thegrooves 82 formed in the middle portion member A synchronous electrical motor 98 (FIG. 5) is secured to a back side of mountingplate 72 and is adaptable to rotate adrive shaft 100 that extends through a mountingplate aperture 102 having a diameter somewhat larger. than the diameter of the drive shaft. ,Thedrive shaft 100 is keyed or otherwise affixed to ancecentric member 104. Themember 104 has an outboard end that pivotally receives apin 106 secured in one end of a pivot link 108. Pivot link 108 has secured in its other end a pin 1.10 pivotally received by the aperture formed in thesecond leg 78B of U.-shapedmember 78.

A range defining member 112 has oneend 114 pivotally secured to linkmember 90 and extends to connect its other end in pivotal engagement at IlZP with one end of arod member 116. The other end ofrod member 116 is secured toshaft 38 and rotates coincidentally therewith. As hereinbefore describedshaft 38 is connected to and controlled by adjustingknob 36.

Note that the control knob selects or fixes the posi tion of pivot 112? and this in turn controls through range of positions that pivot 96 can travel on arcuate path 82 (considering the relative movement between arcuate means 78 and thepivot 96.) This, however, in accordance with a major feature of the present invention determines the vertical strokc distance of drivinglinkage 90 and thus.(through arm 66) of the pump stroke thesyringe 58. The rate of reciprocating of the syringe plungeris determined by the rotation of themotor 98 which is preferably fixed so that the position determines the average pumpingrate. s

The pump unit as described has bee'nconstructed and tested. Empirical data has established that a near linear relationship can be made to-exist between the setting ofknob 36 and-the flow rate and that the average rate of pumping can be precisely controlled over a satisfactory range. y

In order to control the rotation-ofshaft 38 between minimum and maximum limit positions. asindicatcd onscale 34, calibration means 1 l8 isprovided comprising ablock 120, afirst adjustment screws 122 threadably receivable therethrough for establishing a minimum adjustrnent position and-a second adjustment screw I24 threadably receivable by the block for establishing a maximum adjustment position of theshaft 38. It should be noted that either screw when th r caded inwaidly or outawrdly of the block will; upon rotation ofshaft 38,

establish a contact point with-either edge ofrod member 116 and thereby prevent furtherrotation ofshaft 38. Thus. it is possible to adjust therotation'of shaft 38 between minimum and maximum positions so that-opposite correspondence is I maintained withscale 34whenknob 36 is turned to rotateshaft 38 and thereby select a desired rate of fluid infusion.

It can be seen that rotation ofknurled knob 42 causes a magnetic arm I26 affixied thereto'to rotate therewith throughout an angle of substantially-90 as defined bylimit pin 128 protruding from the mounting plate and an exterior side of an enclosedmagnetic switch 130 secured as by screws to the mountingplate 72. The pump assembly is inoperative whenmagnetic arm 126 is engaged withpin 128 and becomes operative whenmagnetic arm 126 is rotated byknob 42 into contact withmagnetic switch 130.Magnetic switch 130 is wired in a known manner. to an insulated terminal assembly 132 (FIGS. 6 and 7) secured to the mountingplate 72.

Referring now to FIG. 6, theUnit 10 is designed to be connected to the commonly available AC power mains (60 hz, 120 v) via a conventional threeprong plug 134 which includes a separate ground male prong for connection to ground. Of course, other power sources and double insulation may be employed without departing from the invention. However, the added ground wiring system is commonly used in hospitals in the US. and provides additional protection against electrical shock and leakage currents which could be very dangerous in this environment of use.

Theplug 134 has threeconductors 134A, 134C and 1346 leading to the unit 10.Conductors 134A and 134C are for the convention AC power and conductor 1346 is connected to the ground prong ofplug 134.

Theground wire 134G is connected to aterminal 146 of aterminal block 132. The terminal146 is securely electrically and physically connected to the housing of theunit 10 to ground that housing.

TheAC power line 134A is connected through a terminal 133 onblock 132 to one side of theswitch 130. As best shown in FIG. 6, theswitch 130 comprised an insulated sealedenvelope housing 130H and a pair of switch blades normally mechanically biased apart switch blades 1308 which are made of magnetic material. When themagnet 126 is moved to the horizontal position the magnetic flux causes the blades to move together and complete the connection through theswitch 130.

The other side ofswitch 130 is connected via aline 136, terminal 138 andline 140 to themotor 98 of the pump assembly. The other side of the motor connects by awire 142 with apost 144 of theterminal assembly 132 which part is, in turn, connected to thepower input line 134C of the power cord.

Theindicator light 150 is connected betweenwires 140 and 142, and is lighted to signal when the motor is running and is off when the motor is shut down.

ln HO. 7 a second preferred embodiment of the invention is illustrated employing, in accordance with a feature of the present invention, means 152 for sensing pressure in the l.V. line to the patient and for automatically shutting off thepump unit 10 in response to a sensed pressure over a selected level.

This means 152, in this embodiment, includes aclosed housing 152H having a diaphragm 152D which is in pressure communication (via a noncompressive, non-conductive fluid inzone 152A and a flexible diaphragm 1521 with the [.V. line to the patent. When the pressure in theIV chamber 152C rises above a threshold level, it moves diaphragm 152D to break the contact of aswitch 168 and disconnect the connection betweenlines 162 and 164.

A twoprong plug 160 is adaptable to be received byreceptacle 154 and includes the twowires 162; 164 leading from the pressuresensitive switch 168. Arelay switch arrangement 172 is disposed along thewire 158 of the device and includes anindicator light 174 for warning-of an overpressure. It should be noted that in theevent pressure sensor 152 reads a pressure considered inimical to the operation of the system, switch 168 will open, causing the light 174 :to light and, more importantly the interruptionof current flow throughswitch 172 to shut downmotor 98 eventhoughmagnetic switch 130 remains in a closed position.

In the operation of the present invention, a supply of intravenous fluid is attached to a stand and from the supply conduit means is connected through thepump apparatus 10 to a vein of a patient as is well known. The pump apparatus is set to a desired'flow of fluid by rotating adjustingknob 36 to the selected point as indicated onscale 34. Knob'42 is rotated from the off to on position and the motor will begin operation to cause'the syringe piston to reciprocate incylinder 56,alternat 'ely drawing fluid into one-way arrangement means '68 on a retraction stroke and forcing fluid out of this means 68 into a vein of apatient on an extension stroke;

The fluid flow setting asaccomplished by'rotating knob 36 is translated into a desired volume of fluid flow by varying amplitude of the syringe piston between positions of full retraction and extension. Rotation ofknob 36 causesrod 116 to turn between thescrews 122, 124 of the calibration means 118 to haveindicator arm 39 point to a desired number onscale 34. I v I Rotational movement ofrod 1 16 to a desired position between, threadablyadjustable screws 122 and 124 forces bar member 112, by virtue of its pinned and articulated relationship with thelink 90, to position the link in a desired position along the curvilinear path defined bygrooves 82 formed in themember 78. Thelink 90 having one end positioned ingrooves 82 and its other end secured substantially intermediate the ends oflever 66 is effective to move thelever 66 through an acutate angle about itsend 70 pivotally secured to mountingplate 72.

It can be seen that rotation of eccentric 104 by the motor causes pivot link 108 to urge thefree end 88 ofmember 78 upwardly and downwardly and thereby define angular displacement about theend 84 ofmember 78 pivotally secured to the mounting plate.Link 90 positioned ingrooves 82 ofmember 78 and connected to lever 66 causes the lever to rotate about itsend 70. The lever in turn translates its angular movement to the rod of thepiston syringe 58 and by virtue of its pivotal connection therewith, causes the piston to move rectilinearly and reciprocatingly within the cylinder of the syringe. Thus, it can be seen that the cooperative construction of the present invention makes it possible by interrelated structure to combine in a unique arrangement angular motion with rectilinear motion to establish a desired amplitude of stroke for a piston syringe. It should be noted that positioning theend 94 of link at any desired point along the curvilinear path defined bygrooves 82 is effective to change the amplitude of the piston stroke and thereby deliver to a patients vein a highly accurate and closely controlled volume of intravenous fluid.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent to those skilled in the art that various changes may be made in the form, construction and arrangement of the component parts without departing from the spirit and scope of the invention or sacrificing all its material advantages, the

form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. Infusion pump apparatus with an adjustable piston stroke amplitude for reciprocating a piston within a syringe to deliver fluid comprising:

a housing;

angulation means pivotally disposed in said housing and operatively connected to said piston to cause said reciprocation of said piston in said syringe; arcuate means pivotally disposed in said housing operatively connected to said angulation means; said arcuate means adaptable to adjustably determine said piston stroke amplitude by varying the displacement of said angulation means: motor means connnected to said arcuate means operable to reciprocate said angulation means through said angular displacement; and

calibration means cooperable with said operative connection between said angulation means and said arcuate means,

said calibration means comprising (a) means for preselecting the fluid flow rate of said infusion pump apparatus by adjusting said displacement of said angulation means, and (b) adjusting means for establishing the minimum and maximum displacement of said angulation means.

2. The infusion pump apparatus ofclaim 1 wherein said adjusting means comprises a plurality of threadably adjustable screws.

3. The infusion pump apparatus ofclaim 1 wherein said angulation means comprises lever means having one end pivotally secured within said housing, said arcuate means comprising a substantially Ushaped member having a middle portion shaped to form a portion of an arc and having grooves formed in said middle portion to define a curvilinear path, link means connected between a point substantially intermediate the ends of said lever means and a point adjustably positioned along said curvilinear path of said U-shaped member, said point of position of said link means along the curvilinear path of said U-shaped member being effective to control the angular distance traveled by said lever and thereby control the amplitude of the syringe piston.

4. The infusion pump apparatus ofclaim 1 wherein said motor means comprises a brushless synchronous electric motor, and magnetic switch means for controlling said motor means between on and off positions, said motor means and said magnetic switch means being adaptable to operate safely in an explosive atmosphere when said switch controls said motor in an operable condition or causes said motor to turn on or off. 5. The infusion pump apparatus ofclaim 3 wherein said motor means comrises a synchronous motor adaptable to operate safely in an explosive atmosphere, an eccentric member keyed to a shaft rotatable by said motor, and a pivot link having one end pivotally connected to said eccentric member and another end pivotally connected to the point of position between said arcuate means and said link means located on the curvilinear path of said U-shaped member.

Claims (5)

1. Infusion pump apparatus with an adjustable piston stroke amplitude for reciprocating a piston within a syringe to deliver fluid comprising: a housing; angulation means pivotally disposed in said housing and operatively connected to said piston to cause said reciprocation of said piston in said syringe; arcuate means pivotally disposed in said housing operatively connected to said angulation means; said arcuate means adaptable to adjustably determine said piston stroke amplitude by varying the displacement of said angulation means: motor means connnected to said arcuate means operable to reciprocate said angulation means through said angular displacement; and calibration means cooperable with said operative connection between said angulation means and said arcuate means, said calibration means comprising (a) means for pre-selecting the fluid flow rate of said infusion pump apparatus by adjusting said displacement of said angulation means, and (b) adjusting means for establishing the minimum and maximum displacement of said angulation means.

2. The infusion pump apparatus of claim 1 wherein said adjusting means comprises a plurality of threadably adjustable screws.

3. The infusion pump apparatus of claim 1 wherein said angulation means comprises lever means having one end pivotally secured within said housing, said arcuate means comprising a substantially U-shaped member having a middle portion shaped to form a portion of an arc and having grooves formed in said middle portion to define a curvilinear path, link means connected between a point substantially intermediate the ends of said lever means and a point adjustably positioned along said curvilinear path of said U-shaped member, said point of position of said link means along the curvilinear path of said U-shaped member being effective to control the angular distance traveled by said lever and thereby control the amplitude of the syringe piston.

4. The infusion pump apparatus of claim 1 wherein said motor means comprises a brushless synchronous electric motor, and magnetic switch means for controllinG said motor means between on and off positions, said motor means and said magnetic switch means being adaptable to operate safely in an explosive atmosphere when said switch controls said motor in an operable condition or causes said motor to turn on or off.

5. The infusion pump apparatus of claim 3 wherein said motor means comrises a synchronous motor adaptable to operate safely in an explosive atmosphere, an eccentric member keyed to a shaft rotatable by said motor, and a pivot link having one end pivotally connected to said eccentric member and another end pivotally connected to the point of position between said arcuate means and said link means located on the curvilinear path of said U-shaped member.

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