Infusion pump

• US 4,838,860 A
• Filed: 06/26/1987
• Issued: 06/13/1989
• Est. Priority Date: 06/26/1987
• Status: Expired due to Term

• Current Assignee: Stanley C., Representative Of Ronald James Brown Deceased Fisher
• Original Assignee: Pump Controller Corporation
• Inventors: Groshong, Judson C., Groshong, Leroy E., Brawn, deceased, R. James
• Primary Examiner(s): Pellegrino, Stephen C.
• Assistant Examiner(s): Lewis, Ralph
• Application Number:
  US07/067,700
• Time in Patent Office: 718 Days
• Field of Search: 604/65, 604/67, 604/131, 604/151, 604/152, 604/153-155, 128/DIG. 12, 128/DIG. 13, 417/534-537, 417/393, 417/510
• US Class Current: 604/152
• CPC Class Codes: A61M 2205/12 with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 5/1422 with double acting or multiple pistons
• CPC Class Codes: Y10S 128/12 Pressure infusion

Abstract

An infusion pump for administering fluid from a fluid source to a patient comprises a base member having an electric motor for driving a fluid pump housed within a cassette detachably mountable on the base and connectable to the motor. The cassette houses a reciprocative piston and cylinder assembly which both pumps fluid to the patient while simultaneously drawing fluid from the fluid source so as to maintain a continuous flow rate of fluid to the patient. The cassette also houses deformably closable pairs of tubes connecting each of the pump'"'"'s two fluid chambers to the cassette inlet and outlet respectively to provide the necessary valving to produce continuous flow in cooperation with the reciprocative piston and cylinder assembly. The fluid flow rate is adjustably controlled by a microcomputer which regulates the motor by repeatedly initiating electric motor driving pulses at a predetermined time rate, and terminating them in response to the advancement of the motor beyond one of a plurality of predetermined positions so as to maximize accuracy and reliability of flow rate while compatibly maximizing the power efficiency of the motor for portable applications requiring a battery power source.

Claims

1. An infusion pump for administering fluid from a fluid to a patient comprising:

(a) a base member;

(b) an electric motor mounted on said base member;

(c) a cassette detachably connected to said base member, said cassette having a fluid inlet for connection to said fluid source and a fluid outlet for connection to said patient; and

(d) pump means, housed within said cassette and having a reciprocative piston assembly detachably connected to said motor and interacting with a pair of fluid chambers on opposite sides of said piston assembly, for pumping fluid through said outlet to said patient at a predetermined volumetric flow rate proportional, by a constant proportionality, that remains constant throughout a stroke of said piston assembly, to the rate of movement of said said inlet from said fluid source at said predetermined volumetric flow rate.

2. The pump of claim 1 wherein said electric motor includes means for imparting reciprocative motion in opposing directions to said piston assembly, and said base member includes means defining a cavity for enclosing said cassette and matingly engaging the exterior of said cassette for preventing movement of said cassette in said opposing directions.

3. An infusion pump for administering fluid from a fluid source to a patient comprising:

(a) a base member;

(b) an electric motor mounted on said base member;

(c) a cassette detachably connected to said base member, said cassette having a fluid inlet for connection to said fluid source and a fluid outlet for connection to said patient;

(d) pump means, housed within said cassette and having a reciprocative piston and cylinder assembly detachably connected to said motor, for pumping fluid through said outlet to said patient at a predetermined volumetric flow rate proportional to the rate of movement of said motor while simultaneously drawing fluid through said inlet from said fluid source at said predetermined volumetric flow rate, said reciprocative piston and cylinder assembly including a pair of fluid chambers within said cassette and means associated with said chambers for alternately decreasing the volume of one of said chambers while correspondingly increasing the volume of the other of said chambers;

(e) valve control motor means mounted on said base member; and

(f) valve means housed within said cassette and detachably connected to said valve control motor means for cooperatively selectively connecting said one of said chambers to said outlet while simultaneously connecting said other of said chambers to said inlet, said valve means comprising two pairs of normally open, deformably closable tubes housed within said cassette, each of said pairs being connected to a respective one of said chambers, the first tube of each pair being connected to said outlet and the second tube of each pair being connected to said inlet, and tube closure means movably mounted on said cassette and detachably connected to said valve control motor means for selectively deformably closing the first tube of one of said pairs of tubes and the second tube of the other of said pairs of tubes simultaneously while allowing the remaining tubes to be open.

4. A cassette for an infusion pump for administering fluid from a fluid source to a patient, said cassette comprising:

(a) means defining a pair of fluid chambers;

(b) piston means for alternately decreasing the volume of one of said chambers while correspondingly increasing the volume of the other of said chambers;

(c) driving means movably mounted with respect to said cassette and detachably engageable externally of said cassette for causing relative reciprocation between said piston means and said chambers;

(d) a fluid inlet and a fluid outlet;

(e) fluid valve means for selectively connecting said one of said chambers to said outlet while simultaneously connecting said other of said chambers to said inlet; and

(f) single valve control means movably mounted on said cassette and detachably engageable externally of said cassette separately from said driving means for alternating the connections of said chambers with respect to said outlet and inlet, respectively.

5. The cassette of claim 4 wherein said driving means and said valve control means are mounted for reciprocative movement along substantially parallel linear paths with respect to said cassette.

6. The cassette of claim 4 wherein said piston means is located between said chambers and said driving means is connected to said piston means for reciprocating said piston means with respect to said chambers.

7. A cassette for a infusion pump for administering fluid from a fluid source to a patient, said cassette comprising:

(a) means defining a pair of fluid chambers;

(b) piston means for alternately decreasing the volume of one of said chambers while correspondingly increasing the volume of the other of said chambers;

(c) driving means movably mounted with respect to said cassette and detachably engageable externally of said cassette for causing relative reciprocation between said piston means and said chambers;

(d) a fluid inlet and a fluid outlet;

(e) fluid valve means for selectively connecting said one of said chambers to said outlet while simultaneously connecting said other of said chambers to said inlet, said valve means comprising two pairs of normally open, deformably closable tubes housed within said cassette, each of said pairs being connected to a respective one of said chambers, the first tube of each pair being connected to said outlet and the second tube of each pair being connected to said inlet;

(f) valve control means movably mounted with respect to said cassette and detachably engageable externally of said cassette for alternating the connections of said chambers with respect to said outlet and inlet, respectively, said valve control means comprising means having a first position for deformably closing the first tube of one said pairs of tubes and the second tube of the other of said pairs of tubes simultaneously, while allowing the remaining tubes to be open.

8. A cassette for an infusion pump for administering fluid from a fluid source to a patient, said cassette comprising:

(a) means defining a fluid chamber;

(b) piston means for alternately decreasing and increasing the volume of said chamber;

(c) driving means movably mounted with respect to said cassette and detachably engageable externally of said cassette for causing relative reciprocation between said piston means and said chamber;

(d) a fluid inlet and a fluid outlet;

(e) fluid valve means for selectively alternatively connecting said chamber to said outlet or inlet, said fluid valve means comprising a pair of normally open, deformably closable tubes housed within said cassette, the first tube of said pair connecting said chamber to said inlet and the second tube of said pair connecting said chamber to said outlet; and

(f) valve control means movably mounted with respect to said cassette and detachably engageable externally of said cassette having a first position for deformably closing said first tube of said pair while allowing said second tube to be open and having a second position for deformably closing said second tube of said pair while allowing said first tube to be open.

9. A method for administering fluid from a fluid source to a patient comprising:

(a) driving the piston assembly of a piston pump, having first and second fluid chambers on opposite sides of said piston assembly, in a first direction by means of an electric motor so as to expel fluid from the first fluid chamber to said patient at a predetermined average volumetric flow rate while simultaneously drawing fluid from said fluid source into said second chamber at said predetermined average volumetric flow rate;

(b) driving the piston assembly of said piston pump in the direction opposite to said first direction by means of said electric motor so as to expel fluid from said second fluid chamber to said patient at said predetermined averaged volumetric flow rate while simultaneously drawing fluid from said fluid source into said first chamber at said predetermined average volumetric flow rate; and

(c) driving the piston assembly of said piston pump in steps (a) and (b) at a rate of movement proportional, by a constant proportionality that remains constant throughout a stroke of said piston assembly, to the rate of movement of said electric motor.

10. An infusion pump for administering fluid from a fluid source to a patient comprising:

(a) a base member;

(b) an electric motor mounted on said base member;

(c) a cassette detachably connected to said base member, said cassette having a fluid inlet for connection to said fluid source and a fluid outlet for connection said patient;

(d) pump means, housed within said cassette and having a reciprocative piston assembly detachably connected to said motor and interacting with a pair of fluid chambers on opposite sides of said piston assembly, for pumping fluid through said outlet to said patient at a pretermined volumetric flow rate proportional, by a constant proportionality, to the rate of movement of said electric motor while simultaneously drawing fluid through said inlet from said fluid source at said predetermined volumetric flow rate;

(e) valve control motor means separate from said electric motor mounted on said base member; and

(f) valve means housed within said cassette having a single valve control means movably mounted on said cassette and detachably connected to said valve control motor means for cooperatively selectively connecting one of said chambers to said outlet while simultaneously connecting the other of said chambers to said inlet and for alternating the connections of said chambers with respect to said outlet and inlet, respectively.