Method and apparatus for detection of occlusions

• US 20020043951A1
• Filed: 12/13/2001
• Published: 04/18/2002
• Est. Priority Date: 10/29/1998
• Status: Active Grant

• Current Assignee: Sheldon Moberg
• Original Assignee: Sheldon Moberg
• Inventors: Moberg, Sheldon
• Granted Patent: US 6,555,986 B2
• Time in Patent Office: Days
• US Class Current: 318/685
• CPC Class Codes: A61M 2005/1623 Details of air intake
• CPC Class Codes: A61M 2039/1033 Swivel nut connectors, e.g. threaded connectors, bayonet-connectors
• CPC Class Codes: A61M 2039/1072 with a septum present in the connector
• CPC Class Codes: A61M 2039/205 comprising air venting means
• CPC Class Codes: A61M 2205/581 by audible feedback
• CPC Class Codes: A61M 2205/582 by tactile feedback
• CPC Class Codes: A61M 39/10 Tube connectors; Tube couplings A61M39/02 takes precedence; connecting needles to syringes or hubs A61M5/34; connecting catheter tubes to hubs A61M25/0014
• CPC Class Codes: A61M 39/12 for joining a flexible tube to a rigid attachment
• CPC Class Codes: A61M 5/14244 adapted to be carried by the patient, e.g. portable on the body
• CPC Class Codes: A61M 5/1452 pressurised by means of pistons
• CPC Class Codes: A61M 5/14566 with a replaceable reservoir for receiving a piston rod of the pump
• CPC Class Codes: A61M 5/162 Needle sets, i.e. connections by puncture between reservoir and tube ; Connections between reservoir and tube in jet-action syringes A61M5/30; connectors for tubes having sealed ends and a needle for piercing them A61M39/14
• CPC Class Codes: A61M 5/16831 Monitoring, detecting, signalling or eliminating infusion flow anomalies low-level float-valves causing cut-off A61M5/40; indicating or recording presence, absence or direction of flow in general G01P13/0066
• CPC Class Codes: Y10T 29/49764 with testing or indicating
• CPC Class Codes: Y10T 29/49826 Assembling or joining
• CPC Class Codes: Y10T 29/53 Means to assemble or disassemble

Abstract

A method and apparatus for automatically detecting an occlusion or drive system failure in a medication infusion system is provided. The electrical current to an infusion pump is measured and compared against a baseline average current. If the current exceeds a threshold amount, an alarm is triggered. Alternatively, pump motor encoder pulses are measured during a pump cycle. If the number of pulses do not correspond within a normal range, an alarm is triggered. After any alarm is triggered, the pump motor is driven in reverse for an incremental distance in order to relieve the fluid pressure in the system.

Claims

1. A method of detecting an occlusion in a fluid pump system, comprising:

measuring a first pump motor current value;

determining whether the first pump motor current value exceeds a second value; and

rewinding the fluid pump system at least to the point of reducing the pressure in the fluid pump system after determining that the first pump motor current value exceeds the second value.

2. The method of claim 1 further comprising providing an alarm indication after determining that the first pump motor current value exceeds the second value.

3. The method of claim 2 further comprising:

calculating a total number of alarm indications after determining that the first pump motor current value exceeds the second value;

determining whether the total number of alarm indications exceeds a third value; and

providing a system error message after determining that the total number of alarm indications exceeds the third value.

4. The method of claim 1 further comprising determining the second value by:

driving the fluid pump system with no fluid pressure present in the fluid pump system;

measuring an intermediate pump motor current value which is used to drive the fluid pump system with no fluid pressure present in the fluid pump system; and

calculating the second value as a function of the intermediate pump motor current value.

5. The method of claim 1 further comprising determining the second value by:

rewinding the fluid pump system;

measuring an intermediate pump motor current value which is used to rewind the fluid pump system; and

calculating the second value as a function of the intermediate pump motor current value.

6. A method of detecting an occlusion in a fluid pump system, comprising:

applying power to a pump motor;

measuring a quantity of fluid delivered by the fluid pump system;

determining whether the quantity of fluid exceeds a first value;

removing power to the pump motor after determining that the quantity of fluid exceeds the first value;

measuring a first pump motor current value;

determining whether the first pump motor current value exceeds a second value;

removing power to the pump motor after determining that the first pump motor current value exceeds the second value;

rewinding the fluid pump system at least to the point of reducing the pressure in the fluid pump system after determining that the first pump motor current value exceeds the second value;

providing an alarm indication after determining that the first pump motor current value exceeds the second value;

calculating a total number of alarm indications after determining that the first pump motor current value exceeds the second value;

determining whether the total number of alarm indications exceeds a third value; and

providing a system error message after determining that the total number of alarm indications exceeds the third value.

7. A system for detecting an occlusion in a fluid pump system, comprising:

a processing unit capable of communicating with the fluid pump system; and

program logic executed by the processing unit, comprising;

means for measuring a first pump motor current value;

means for determining whether the first pump motor current value exceeds a second value; and

means for rewinding the fluid pump system at least to the point of reducing the pressure in the fluid pump system after determining that the first pump motor current value exceeds the second value.

8. The system claimed in claim 7 wherein the program logic further comprises means for providing an alarm indication after determining that the first pump motor current value exceeds the second value.

9. The system claimed in claim 8 wherein the program logic further comprises:

means for calculating a total number of alarm indications after determining that the first pump motor current value exceeds the second value;

means for determining whether the total number of alarm indications exceeds a third value; and

means for providing a system error message after determining that the total number of alarm indications exceeds the third value.

10. The system claimed in claim 7 wherein the program logic further comprises:

means for driving the fluid pump system with no fluid pressure present in the fluid pump system;

means for measuring an intermediate pump motor current value which is used to drive the fluid pump system with no fluid pressure present in the fluid pump system; and

means for calculating the second value as a function of the intermediate pump motor current value.

11. The system claimed in claim 7 wherein the program logic further comprises:

means for rewinding the fluid pump system;

means for measuring an intermediate pump motor current value which is used to rewind the fluid pump system; and

means for calculating the second value as a function of the intermediate pump motor current value.

14. The method of claim 13 further comprising rewinding the fluid pump system at least to the point of reducing pressure in the fluid pump system after determining that the first encoder count is less than the first value.

15. The method of claim 13 further comprising providing an alarm indication after determining that the first encoder count is less than the first value.

16. The method of claim 15 further comprising:

calculating a total number of alarm indications after determining that the first encoder count is less than the first value;

determining whether the total number of alarm indications exceeds a second value; and

providing a system error message after determining that the total number of alarm indications exceeds the second value.

17. The method of claim 13 further comprising:

determining whether the first encoder count is equal to a third value; and

adjusting the input power parameters to provide a second pump cycle after determining that the first encoder count does not equal the third value, said second pump cycle resulting in a second encoder count, said second encoder count being one of a value greater than the first encoder count if the first encoder count is less than the third value and a value smaller than the first encoder count if the first encoder count is greater than the third value.

20. The system of claim 19 wherein the program logic further comprises means for rewinding the fluid pump system at least to the point of reducing pressure in the fluid pump system after determining that the first encoder count is less than the first value.

21. The system of claim 19 wherein the program logic further comprises means for providing an alarm indication after determining that the first encoder count is less than the first value.

22. The system of claim 21 wherein the program logic further comprises:

means for calculating a total number of alarm indications after determining that the first encoder count is less than the first value;

means for determining whether the total number of alarm indications exceeds a second value; and

means for providing a system error message after determining that the total number of alarm indications exceeds the second value.

23. The system of claim 19 wherein the program logic further comprises:

means for determining whether the first encoder count is equal to a third value; and

means for adjusting the input power parameters to provide a second pump cycle after determining that the first encoder count does not equal the third value, said second pump cycle resulting in a second encoder count, said second encoder count being one of a value greater than the first encoder count if the first encoder count is less than the third value and a value smaller than the first encoder count if the first encoder count is greater than the third value.

26. The method of claim 25 further comprising rewinding the fluid pump system at least to the point of reducing pressure in the fluid pump system after determining that the torque value is greater than the first value.

27. The method of claim 25 further comprising providing an alarm indication after determining that the torque value is greater than the first value.

28. The method of claim 27 further comprising:

calculating a total number of alarm indications after determining that the torque value is greater than the first value;

determining whether the total number of alarm indications exceeds a second value; and

providing a system error message after determining that the total number of alarm indications exceeds the second value.

12. A system for detecting an occlusion in a fluid pump system, comprising:

a processing unit capable of communicating with the fluid pump system; and

program logic executed by the processing unit, comprising;

means for applying power to a pump motor;

means for measuring a quantity of fluid delivered by the fluid pump system;

means for determining whether the quantity of fluid exceeds a first value;

means for removing power to the pump motor after determining that the quantity of fluid exceeds the first value;

means for measuring a first pump motor current value;

means for determining whether the first pump motor current value exceeds a second value;

means for removing power to the pump motor after determining that the first pump motor current value exceeds the second value;

means for rewinding the fluid pump system at least to the point of reducing the pressure in the fluid pump system after determining that the first pump motor current value exceeds the second value;

means for providing an alarm indication after determining that the first pump motor current value exceeds the second value;

means for calculating a total number of alarm indications after determining that the first pump motor current value exceeds the second value;

means for determining whether the total number of alarm indications exceeds a third value; and

means for providing a system error message after determining that the total number of alarm indications exceeds the third value.

13. A method of detecting an occlusion in a fluid pump system, comprising:

applying input power parameters to a pump motor to provide a first pump cycle;

measuring a first encoder count during the first pump cycle; and

determining whether the first encoder count is less than a first value.

18. A method of detecting an occlusion in a fluid pump system, comprising:

applying input power parameters to a pump motor to provide a first pump cycle;

measuring a first encoder count during the first pump cycle;

determining whether the first encoder count is less than a first value;

rewinding the fluid pump system at least to the point of reducing pressure in the fluid pump system after determining that the first encoder count is less than the first value;

providing an alarm indication after determining that the first encoder count is less than the first value;

calculating a total number of alarm indications after determining that the first encoder count is less than the first value;

determining whether the total number of alarm indications exceeds a second value;

providing a system error message after determining that the total number of alarm indications exceeds the second value;

determining whether the first encoder count is equal to a third value; and

adjusting the input power parameters to provide a second pump cycle after determining that the first encoder count does not equal the third value, said second pump cycle resulting in a second encoder count, said second encoder count being one of a value greater than the first encoder count if the first encoder count is less than the third value and a value smaller than the first encoder count if the first encoder count is greater than the third value.

19. A system for detecting an occlusion in a fluid pump system, comprising:

a processing unit capable of communicating with the fluid pump system; and

program logic executed by the processing unit, comprising;

means for applying input power parameters to a pump motor to provide a first pump cycle;

means for measuring a first encoder count during the first pump cycle; and

means for determining whether the first encoder count is less than a first value.

24. A system for detecting an occlusion in a fluid pump system, comprising:

a processing unit capable of communicating with the fluid pump system; and

program logic executed by the processing unit, comprising;

means for applying input power parameters to a pump motor to provide a first pump cycle;

means for measuring a first encoder count during the first pump cycle;

means for determining whether the first encoder count is less than a first value;

means for rewinding the fluid pump system at least to the point of reducing pressure in the fluid pump system after determining that the first encoder count is less than the first value;

means for providing an alarm indication after determining that the first encoder count is less than the first value;

means for calculating a total number of alarm indications after determining that the first encoder count is less than the first value;

means for determining whether the total number of alarm indications exceeds a second value;

means for providing a system error message after determining that the total number of alarm indications exceeds the second value;

means for determining whether the first encoder count is equal to a third value; and

means for adjusting the input power parameters to provide a second pump cycle after determining that the first encoder count does not equal the third value, said second pump cycle resulting in a second encoder count, said second encoder count being one of a value greater than the first encoder count if the first encoder count is less than the third value and a value smaller than the first encoder count if the first encoder count is greater than the third value.

25. A method of detecting an occlusion in a fluid pump system, comprising:

applying an input power parameter to a pump motor to provide a pump cycle;

measuring an encoder count during the pump cycle;

determining a torque value as a function of the encoder count and the input power parameter; and

determining whether the torque value is greater than a first value.

29. A method for detecting an occlusion in a fluid pump system, comprising:

applying an input power parameter to a pump motor to provide a pump cycle;

measuring an encoder count during the pump cycle;

determining a torque value as a function of the encoder count and the input power parameter;

determining whether the torque value is greater than a first value;

rewinding the fluid pump system at least to the point of reducing pressure in the fluid pump system after determining that the torque value is greater than the first value;

providing an alarm indication after determining that the torque value is greater than the first value;

calculating a total number of alarm indications after determining that the torque value is greater than the first value;

determining whether the total number of alarm indications exceeds a second value; and

providing a system error message after determining that the total number of alarm indications exceeds the second value.

30. A system for detecting an occlusion in a fluid pump system, comprising:

a processing unit capable of communicating with the fluid pump system; and

program logic executed by the processing unit, comprising;

means for applying an input power parameter to a pump motor to provide a pump cycle;

means for measuring an encoder count during the pump cycle;

means for determining a torque value as a function of the encoder count and the input power parameter; and

means for determining whether the torque value is greater than a first value.

31. The system of claim 30 wherein the program logic further comprises means for rewinding the fluid pump system at least to the point of reducing pressure in the fluid pump system after determining that the torque value is greater than the first value.

32. The system of claim 30 wherein the program logic further comprises means for providing an alarm indication after determining that the torque value is greater than the first value.

33. The system of claim 32 wherein the program logic further comprises:

means for calculating a total number of alarm indications after determining that the torque value is greater than the first value;

means for determining whether the total number of alarm indications exceeds a second value; and

means for providing a system error message after determining that the total number of alarm indications exceeds the second value.

36. The method of claim 35 wherein said measured pump motor parameter of operation includes one or more of motor current, motor voltage, motor rotational displacement, motor linear displacement, motor speed, motor acceleration, motor deceleration and motor torque.

34. A system for detecting an occlusion in a fluid pump system, comprising:

a processing unit capable of communicating with the fluid pump system; and

program logic executed by the processing unit, comprising;

means for applying an input power parameter to a pump motor to provide a pump cycle;

means for measuring an encoder count during the pump cycle;

means for determining a torque value as a function of the encoder count and the input power parameter;

means for determining whether the torque value is greater than a first value;

means for rewinding the fluid pump system at least to the point of reducing pressure in the fluid pump system after determining that the torque value is greater than the first value;

means for providing an alarm indication after determining that the torque value is greater than the first value;

means for calculating a total number of alarm indications after determining that the torque value is greater than the first value;

means for determining whether the total number of alarm indications exceeds a second value; and

means for providing a system error message after determining that the total number of alarm indications exceeds the second value.

35. A method of detecting an occlusion in a fluid pump system, comprising:

measuring a pump motor parameter of operation;

determining whether the measured pump motor parameter of operation exceeds a predetermined value; and

rewinding the fluid pump system at least to the point of reducing the pressure in the fluid pump system after determining that the measured pump motor parameter of operation value exceeds the predetermined value.

37. An apparatus for detecting an occlusion in a fluid pump system, comprising a controller configured and adapted to:

measure a pump motor parameter of operation;

determine whether the measured pump motor parameter of operation exceeds a predetermined value; and

rewind the fluid pump system at least to the point of reducing the pressure in the fluid pump system after determining that the measured pump motor parameter of operation value exceeds the predetermined value.