Infusion pump with a sealed drive mechanism and improved method of occlusion detection

• US 20020128594A1
• Filed: 05/07/2002
• Published: 09/12/2002
• Est. Priority Date: 06/18/1999
• Status: Active Grant

• Current Assignee: LifeScan IP Holdings, LLC
• Original Assignee: Animas Corporation (Johnson & Johnson)
• Inventors: Das, Kusal K., Shipway, Ian Maxwell
• Granted Patent: US 6,656,148 B2
• Time in Patent Office: Days
• US Class Current: 604/67
• CPC Class Codes: A61M 2005/14573 with a replaceable reservoir for quick connection/disconnection with a driving system
• CPC Class Codes: A61M 5/1456 with a replaceable reservoir comprising a piston rod to be moved into the reservoir, e.g. the piston rod is part of the removable reservoir
• CPC Class Codes: A61M 5/16854 by monitoring line pressure
• CPC Class Codes: Y10S 128/01 Motorized syringe
• CPC Class Codes: Y10S 128/12 Pressure infusion

Abstract

A piston-type infusion pump is provided having an improved method of occlusion detection. The infusion pump includes processing circuitry for controlling the drive mechanism to infuse medication to a patient, including a sensor to track the position of the syringe plunger, thereby metering the amount of medication dispensed to the patient. The processing circuitry also includes a force sensor for providing signals indicative of the presence of occlusions along the infusion path. The operation of the drive mechanism causes delivery of medication to the patient. The infusion pump is constructed to be watertight.

Claims

1. An occlusion detector for use with an infusion pump for dispensing volumetrically proportioned doses of pharmaceutical product to a patient, the infusion pump having a pharmaceutical storage area for containing a supply of pharmaceutical product and adapted to be connected to, an infusion path between the storage area and the patient, an incrementally operated urging mechanism for urging contents of the storage area to infuse a volumetrically proportioned dose of the contents along the infusion path to the patient, the urging mechanism traveling a complete increment in a delivery cycle, and a drive mechanism operably linked to the urging mechanism to control the incremental movement of the urging mechanism for dispensing a volumetrically proportioned dose of pharmaceutical product to the patient by way of the infusion path, the occlusion detector comprising:

a force transducer for providing a signal representative of the level of force incident to the urging mechanism within the storage area;

a memory for storing information representative of the transducer signals;

a processor, the processor monitoring the force transducer to receive a signal prior to actuation of the drive mechanism for dispensing of pharmaceutical product along the infusion path, the signal defined as a cycle signal, storing the cycle signal in the memory, comparing the cycle signal to a previous cycle signal in the memory to identify an increase in force incident to the urging mechanism within the storage area; and

an alarm, triggered by the processor upon the identification of a predetermined number of increasing cycle signals whereby the increasing signals indicate an occlusion in the infusion path triggering the alarm to alert the patient.

2. The occlusion detector of claim 1 wherein the force transducer is monitored immediately prior to the actuation of the drive mechanism.

3. The occlusion detector of claim 2 wherein the processor compares a basal rate of the infusion to a predetermined basal rate prior to comparing the cycle signals information.

4. The occlusion detector of claim 3 wherein cycle signals below the predetermined basal rate of infusion are compared to a predetermined signal value and cycle signals exceeding said predetermined signal value by a predetermined amount trigger the alarm.

5. A method of detecting an occlusion along an infusion path of an infusion pump having a pharmaceutical storage area for containing a supply of pharmaceutical product, and adapted to be connected to the infusion path between the storage area and a patient, an incrementally engaged urging mechanism for urging contents of the storage area to infuse a volumetrically proportioned dose of the contents along the infusion path to the patient, a force transducer for providing a signal representative of the force incident to the urging mechanism within the storage area, and a drive mechanism operably linked to the urging mechanism to control the incremental movement of the urging mechanism for dispensing a volumetrically proportioned dose of pharmaceutical product to the patient by way of the infusion path, the method comprising:

monitoring the signal of the force transducer prior to delivery cycles and the actuation of the drive mechanism for delivering a dose of pharmaceutical product to the patient, the signal defined as a cycle signal;

storing information representative of the cycle signals of the force transducer in a memory;

comparing a current cycle signal of the force transducer to a previous cycle signal stored in the memory for identifying an increase in force incident to the urging mechanism within the storage area;

determining whether the current cycle signal level has increased over the preceding cycle signal level;

counting each such increase; and

activating an alarm when a predetermined number of force increases have been counted.

6. The method of claim 5 wherein the alarm is activated upon monitoring a predetermined number of sequential cycle increases.

7. The method of claim 5 further comprising the step of comparing the cycle signals to a predetermined value and activating the alarm if a cycle signal is greater than the predetermined value.

8. The method of claim 5 further comprising the step of comparing the cycle signals to a predetermined value and activating the alarm if a cycle signal is less than the predetermined value.

9. The method of claim 5 wherein the monitoring function is performed by a processor.

10. A method of detecting an occlusion along an infusion path of an infusion pump having a pharmaceutical storage area for containing a supply of pharmaceutical product adapted to be connected to the infusion path between the storage area and a patient, an incrementally operated urging mechanism for urging contents of the storage area to infuse a volumetrically proportioned dose of the contents along the infusion path to the patient, a force transducer for providing a signal representative of the force incident to the urging mechanism within the storage area, and a drive mechanism operably linked to the urging mechanism to control the incremental movement of the urging mechanism for dispensing a volumetrically proportioned dose of pharmaceutical product to the patient by way of the infusion path, the method comprising:

monitoring the signal of the force transducer prior to delivery cycles and the actuation of the drive mechanism for delivering a dose of pharmaceutical product to the patient, the signal defined as a cycle signal;

storing information representative of the force transducer cycle signal in a memory;

comparing a current cycle signal of the force transducer to a previous cycle signal stored in the memory for identifying an increase in force incident to the urging mechanism within the storage area;

determining whether the current cycle signal level has increased over the preceding cycle signal level by an amount greater than a predetermined value; and

activating an alarm when the current cycle signal has increased over the preceding cycle signal by an amount greater than the predetermined value.

11. A method of detecting an occlusion along an infusion path of an infusion pump having a pharmaceutical storage area for containing a supply of pharmaceutical product adapted to be connected to the infusion path between the storage area and a patient, an incrementally engaged urging mechanism for urging contents of the storage area to infuse a volumetrically proportioned dose of the contents along the infusion path to the patient, a force transducer for providing a signal representative of the force incident to the urging mechanism within the storage area, and a drive mechanism operably linked to the urging mechanism to control the incremental movement of the urging mechanism for dispensing a volumetrically proportioned dose of pharmaceutical product to the patient by way of the infusion path, the method comprising:

monitoring the signal of the force transducer prior to delivery cycles and the actuation of the drive mechanism for delivering a dose of pharmaceutical product to the patient, the signal defined as a cycle signal;

determining whether the basal rate of the pharmaceutical delivery is less than a predetermined rate;

determining whether a current cycle signal for a basal rate less than the predetermined rate is less than a predetermined minimum value;

comparing the cycle signal of the force transducer to the predetermined minimum value;

determining whether the current cycle signal level has increased over the predetermined minimum value by more than a predetermined amount; and

activating an alarm upon the determination of a force increase above the predetermined amount.

13. The system fault detector of claim 12 wherein the processor further compares the basal rate of infusion to a predetermined basal rate prior to comparing the current force signal with the previous force signal, and wherein the processor compares the current force signal to a predetermined minimal signal level if the basal rate is below the predetermined basal rate of infusion, and triggers an alarm if the current force signal exceeds the predetermined minimal signal level by a predetermined amount.

14. The system fault detector of claim 12 wherein the processor further compares the current force signal to a predetermined maximum value and triggers the alarm if the current force signal is greater than the predetermined maximum value.

15. The system fault detector of claim 12 wherein the processor further compares the current force signal to a predetermined minimum value and triggers the alarm if the current force signal is less than the predetermined minimum value.

16. The system fault detector of claim 12 wherein the processor further compares the current force signal to the previous force signal and triggers the alarm if the current force signal is greater than the previous force signal by a predetermined value.

12. A system fault detector for use with an infusion pump for dispensing volumetrically proportioned doses of pharmaceutical product to a patient, the system fault detector comprising:

a force transducer for providing signals representative of the level of force applied to an urging mechanism within the storage area; and

a processor for monitoring and processing the signals from the force transducer and controlling a drive mechanism, wherein the processor receives a current force signal from the force transducer immediately prior to actuating the drive mechanism during a delivery cycle, compares the current force signal to a previous force signal from a prior delivery cycle to identify an increase in force indicating an occlusion in the infusion path and/or storage area, and generates a signal to actuate an alarm upon identification of a predetermined number, which is greater than 1, of current force signal increases over respective previous force signals.

17. A method of detecting an occlusion along an infusion path and/or within a storage area of an infusion pump, the method comprising:

monitoring signals from a force transducer prior to a plurality of pump delivery cycles, to detect the force incident to an urging mechanism within the infusion pump;

storing information representative of the force signals in a memory for the plurality of delivery cycles;

comparing a force signal for a current delivery cycle to a force signal for a previous delivery cycle to determine whether the force signal for the current delivery cycle represents a force increase over the force signal for the previous delivery cycle;

counting the number of sequential increases in force between pump delivery cycles; and

activating an alarm when a predetermined number of force increases have been counted.

18. A method of detecting an occlusion along an infusion path and/or within a storage area of an infusion pump, the method comprising:

monitoring signals from a force transducer prior to a plurality of pump delivery cycles, to detect the force incident to an urging mechanism within the infusion pump;

storing information representative of the force signals in a memory for the plurality of pump delivery cycles;

comparing a force signal for a current delivery cycle, defined as a current force signal, to a force signal for a previous delivery cycle, defined as a previous force signal, to determine whether the current force signal represents a force increase over the previous force signal by an amount greater than a predetermined value; and

activating an alarm if the current force signal has increased over the previous force signal by an amount greater than the predetermined value.

19. A method of detecting an occlusion along an infusion path and/or within a storage area of an infusion pump, the method comprising:

monitoring signals from a force transducer prior to a plurality of pump delivery cycles, to detect the force incident to an urging mechanism within the infusion pump;

determining whether the basal rate of a current delivery cycle is less than a predetermined rate;

if the basal rate is less than the predetermined rate, determining whether a force signal for the current delivery cycle, defined as a current force signal, represents a force level less than a minimum force level;

if the current force signal is less then the minimum force level, storing the current force signal in a memory as the minimum force level;

if the current force signal is greater than the minimum force level, determining if the current force signal represents a force level higher than the minimum force level by an amount greater than a predetermined force increase value; and

activating an alarm upon determination of a force increase greater than the predetermined force increase value.

20. A method of detecting an occlusion along an infusion path and/or within a storage area of an infusion pump, the method comprising:

monitoring signals from a force transducer prior to a plurality of pump delivery cycles, to detect the force incident to an urging mechanism within the infusion pump;

comparing a force signal for a current delivery cycle to a predetermined maximum value; and

activating an alarm if the force signal for the current delivery cycle exceeds the predetermined maximum value.

21. A method of detecting leakage along an infusion path and/or within a storage area of an infusion pump, the method comprising:

monitoring signals from a force transducer prior to a plurality of pump delivery cycles, to detect the force incident to an urging mechanism within the infusion pump;

comparing a force signal for a current delivery cycle to a predetermined minimum value; and

activating an alarm if the force signal for the current delivery cycle is less than the predetermined minimum value.