Infusion pump

• US 4,898,579 A
• Filed: 06/03/1988
• Issued: 02/06/1990
• Est. Priority Date: 06/26/1987
• Status: Expired due to Term

• Current Assignee: Pump Controller Corporation
• Original Assignee: Pump Controller Corporation
• Inventors: Groshong, Judson C., Groshong, Leroy E., Brawn, deceased, R. James
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Lewis, Ralph
• Application Number:
  US07/201,951
• Time in Patent Office: 613 Days
• Field of Search: 128/DIG. 1, 128/DIG. 12, 128/DIG. 13, 604/31, 604/65, 604/67, 604/131, 604/151-155
• US Class Current: 604/67
• 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 adjustable 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 source through an outlet to a patient at a controlled average volumetric flow rate comprising:

(a) pump means for pumping fluid from said fluid source through said outlet at an average volumetric flow rate proportional to the average rate of movement of said pump means;

(b) electric motor means for moving said pump means; and

(c) control means for controlling the average rate at which said electric motor means moves said pump means, said control means comprising time-based means for repeatedly initiating motor-driving electric energy at a predetermined time rate, and position-based means for repeatedly terminating said energy in response to the advancement of said motor means beyond respective predetermined positions after respective initiations of said energy, said respective predetermined positions being separated by identical increments of movement of said motor means;

(d) said electric motor means comprising a rotary brushless permanent magnet motor, having a rotor with permanent magnet poles and magnetic field sensor means for sensing the magnetic fields of said poles and thereby indicating the angular position of said rotor, said position-based means being responsive to the position of said rotor as indicated by said magnetic field sensor means.

2. The pump of claim 1 wherein said position-based means comprises means for enabling nonuniform durations of time between each successive initiation and termination of said energy.

3. An infusion pump for administering fluid from a fluid source through an outlet to a patient at a controlled average volumetric flow rate comprising:

(a) pump means for pumping fluid from said fluid source through said outlet at an average volumetric flow rate proportional to the average rate of movement of said pump means;

(b) electric motor means for moving said pump means;

(c) control means for controlling the average rate at which said electric motor means moves said pump means, said control means comprising time-based means for repeatedly initiating motor-driving electric energy at a predetermined time rate, and position-based means for repeatedly terminating said energy in response to the advancement of said motor means beyond respective predetermined positions after respective initiations of said energy, said respective predetermined positions being separated by identical increments of movement of said motor means; and

(d) comparator means for sensing whether or not said motor means has advanced beyond one of said increments of movement within a predetermined time period after an initiation of said energy.

4. The pump of claim 3, including means, responsive to said comparator means, for counting the number of times said motor means does not so advance, and transmitting an error signal in response to said number of times exceeding a predetermined number.

5. The pump of claim 4, including means for reinitiating said counting in response to the pumping of a predetermined volume of fluid by said pump.

6. The pump of claim 3 including means responsive to said comparator means for counting the number of times said motor means does so advance.

7. An infusion pump for administering fluid from a fluid source through an outlet to a patient, comprising:

(a) fluid pump means connected to said fluid source and said outlet for pumping fluid from said fluid source through said outlet at a predetermined average volumetric flow rate;

(b) electric motor means for driving said pump means;

(c) sensor means for sensing the average rate of movement of said motor means;

(d) means responsive to said sensor means for transmitting an error signal when the average rate of movement of said motor means, as sensed by said sensor means, is below a predetermined rate; and

(e) means for controllably varying the time-averaged magnitude of electric current driving said motor means, so as to controllably vary the maximum pressure of said fluid pumped through said outlet, independently of the magnitude of said predetermined average volumetric flow rate so as to maintain said predetermined average volumetric flow rate in case of a partial occlusion tending to reduce said volumetric flow rate.

8. The pump of claim 7 wherein said sensor means includes means for sensing the average rate of movement of said motor means separately for separate predetermined volumes of fluid pumped by said pump means.

9. An infusion pump for administering fluid from a fluid source through an outlet to a patient at a controlled average volumetric flow rate comprising:

(a) pump means for pumping fluid from said fluid source through said outlet at an average volumetric flow rate proportional to the average rate of movement of said pump means;

(b) electric motor means for moving said pump means; and

(c) control means for controlling the average rate at which said electric motor means moves said pump means, said control means comprising time-based means for repeatedly initiating motor-driving electric energy at a predetermined time rate, position sensor means for sensing the position of said motor, and position-based means responsive to said position sensor means for repeatedly terminating said energy, said position-based means including means for terminating said energy concurrently with the advancement of said motor means beyond respective predetermined positions after the most recent initiation of said energy irrespective of the time elapsed since said most recent initiation, successive ones of said respective predetermined positions being separated by identical increments of movement of said motor means; and

(d) said means comprising reciprocative piston and cylinder means for pumping fluid through said outlet at said controlled average volumetric flow rate while simultaneously drawing fluid from said fluid source at said controlled average volumetric flow rate.

10. An infusion pump for administering fluid from a fluid source through an outlet to a patient, comprising:

(a) fluid pump means connected to said fluid source and said outlet for pumping fluid from said fluid source through said outlet at a predetermined average volumetric flow rate;

(b) electric motor means for driving said pump means;

(c) sensor means for sensing regressive movement of said motor means in a direction opposite to that in which said motor means drives said pump means; and

(d) control means responsive to said sensor means for initiating motor-driving electrical energy opposing said regressive movement in response to the sensing by said sensor means of said regressive movement.