Ambulatory medical apparatus and method using a telemetry system with predefined reception listening

• US 20030069614A1
• Filed: 07/29/2002
• Published: 04/10/2003
• Est. Priority Date: 01/21/2000
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Villegas, Daniel H., Lebel, Ronald J., Gord, John C., Bowman, Sam W. IV
• Granted Patent: US 6,950,708 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: A61B 2560/0209 adapted for power saving
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/6847 mounted on an invasive device
• CPC Class Codes: A61M 2005/14208 with a programmable infusion control system, characterised by the infusion program
• CPC Class Codes: A61M 2205/18 with alarm
• CPC Class Codes: A61M 2205/3507 with implanted devices, e.g. external control
• CPC Class Codes: A61M 2205/3523 using telemetric means
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2205/581 by audible feedback
• CPC Class Codes: A61M 2205/582 by tactile feedback
• CPC Class Codes: A61M 2205/6018 providing set-up signals for the apparatus configuration
• CPC Class Codes: A61M 2205/8206 battery-operated
• CPC Class Codes: A61M 2207/00 Methods of manufacture, assembly or production
• CPC Class Codes: A61M 5/14244 adapted to be carried by the patient, e.g. portable on the body
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/168 Means for controlling media flow to the body or for metering media to the body, e.g. drip meters, counters ; Monitoring media flow to the body flow control in general G05D7/00
• 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: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence
• CPC Class Codes: A61N 1/37211 Means for communicating with stimulators
• CPC Class Codes: A61N 1/37247 : User interfaces, e.g. input or presentation means
• CPC Class Codes: A61N 1/37254 : Pacemaker or defibrillator security, e.g. to prevent or inhibit programming alterations by hackers or unauthorised individuals
• CPC Class Codes: A61N 1/37258 : Alerting the patient
• CPC Class Codes: A61N 1/37264 : Changing the program; Upgrading firmware
• CPC Class Codes: A61N 1/3727 : characterised by the modulation technique
• CPC Class Codes: A61N 1/37276 : characterised by means for reducing power consumption during telemetry
• CPC Class Codes: A61N 1/37512 : Pacemakers
• CPC Class Codes: G06F 3/0619 : in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/065 : Replication mechanisms
• CPC Class Codes: G06F 3/0673 : Single storage device
• CPC Class Codes: G06F 8/60 : Software deployment
• CPC Class Codes: G06F 8/65 : Updates security arrangements therefor G06F21/57
• CPC Class Codes: G16H 20/17 : delivered via infusion or injection
• CPC Class Codes: G16H 40/40 : for the management of medical equipment or devices, e.g. scheduling maintenance or upgrades
• CPC Class Codes: Y02D 10/00 : Energy efficient computing, e.g. low power processors, power management or thermal management
• CPC Class Codes: Y10S 128/13 : Infusion monitoring
• CPC Class Codes: Y10S 128/903 : Radio telemetry
• CPC Class Codes: Y10T 29/49117 : Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/49826 : Assembling or joining

Abstract

An implanted medical device (e.g. infusion pump) and an external device communicate with one another via telemetry messages that are receivable only during windows or listening periods. Each listening period is open for a prescribed period of time and is spaced from successive listening periods by an interval. The prescribed period of time is typically kept small to minimize power consumption. To increase likelihood of successful communication, the window may be forced to an open state, by use of an attention signal, in anticipation of an incoming message. To further minimize power consumption, it is desirable to minimize use of extended attention signals, which is accomplished by the transmitter maintaining an estimate of listening period start times and attempting to send messages only during listening periods. In the communication device, the estimate is updated as a result of information obtained with the reception of each message from the medical device.

Claims

1. A medical system, comprising:

a) an ambulatory medical device (MD) comprising MD electronic control circuitry that further comprises at least one MD telemetry system and at least one MD processor that controls, at least in part, operation of the MD telemetry system and operation of the medical device, wherein the medical device is configured to provide a treatment to a body of a patient or to monitor a selected state of the body; and

b) a communication device (CD) comprising CD electronic control circuitry that further comprises at least one CD telemetry system and at least one CD processor that controls, at least in part, operation of the CD telemetry system and operation of the communication device, wherein the CD telemetry system sends messages to or receives messages from the MD telemetry system,

wherein the medical device or the communication device comprises an oscillator circuit that produces a pulse stream that oscillates at an initial frequency that is greater than a desired frequency and wherein signals from the oscillator circuit are passed through circuitry that removes selected pulses from an input pulse stream such that a modified oscillator signal is produced having a modified pulse stream that oscillates with an average frequency closer to a desired frequency than the initial frequency.

2. The system of claim 1 wherein a first portion of the MD telemetry system is incorporated into the MD processor and a second portion of the MD telemetry system is external to the MD processor, or wherein a first portion of the CD telemetry system is incorporated into the CD processor and a second portion of the CD telemetry system is external to the CD processor.

3. The system of claim 2 wherein (1) the MD electronic control circuitry comprises at least one external MD functional module, other than the second portion of the MD telemetry system, that is external to the MD processor, (2) the CD electronic control circuitry comprises at least one external CD functional module, other than the second portion of the CD telemetry system, that is external to the CD processor, (3) the MD processor comprises an internal MD CPU and at least one other internal MD functional module, or (4) the CD processor comprises an internal CD CPU and at least one other internal CD functional module.

4. The system of claim 1 wherein the modified pulse stream is used to generate a system timing signal that has a frequency less than that of the modified pulse stream.

5. The system of claim 1 wherein the timing signal has a frequency less than about {fraction (1/100)} of the average frequency of the modified pulse stream.

6. The system of claim 4 wherein both the medical device and the communication device produce at least one timing signal from a modified pulse stream.

7. The system of claim 1 wherein the average frequency of the modified pulse stream is no less than 90% of the initial pulse stream.

8. The system of claim 7 wherein the average frequency of the modified pulse stream is no less than 99% of the frequency of the initial pulse stream.

9. The system of claim 1 wherein in the circuitry comprises a counter that repetitively counts to a first predefined value and then removes a pulse from the initial pulse stream to produce the modified pulse stream.

10. The system of claim 9 wherein a timing signal is generated from the modified pulse stream by utilization of a counter that counts to a second predefined value and then outputs a pulse.

11. The system of claim 10 wherein the first predefined value is defined by software.

12. The system of claim 11 wherein the first predefined value is subject to modification during a normal course of operation of the medical system.

13. The system of claim 12 wherein the modification of the first predefined value causes the modified pulse stream to oscillate at a frequency closer to the desired frequency than it otherwise would if it remained unchanged.

14. The system of claim 12 wherein the initial frequency varies with temperature of the oscillator circuit and wherein the modification of the first predefined value is based at least in part on (1) an anticipated change in the initial oscillation frequency as a function of temperature, and (2) on an estimated or measured temperature, or variations in temperature, of the oscillator circuit.

15. The system of claim 11 wherein the second predefined value is defined by software.

16. The system of claim 11 wherein the second predefined value is defined by hardware.

17. The system of claim 1 wherein the initial pulse stream is provided, at least indirectly, from a crystal oscillator circuit that has an oscillation frequency at least somewhat greater than that to be used in a given application.

18. The system of claim 17 wherein the crystal oscillator circuit has a stability that is acceptable for the given application but has an oscillation tolerance greater than that acceptable for the given application.

19. The system of claim 18 wherein an oscillator is selected for use in the given application that has a lower oscillation frequency tolerance limit that is greater than the desired oscillation frequency for the given application.

20. The system of claim 4 wherein the circuitry is activated to steal one two or more consecutive pulses from the initial pulse stream.

21. The system of claim 20 wherein the circuitry is activated upon receipt of a pulse from at least one counter.

22. The system of claim 9 wherein the first predefined value is modifiable by software.

23. The system of claim 22 wherein the first predefined value is, at least in part, modified based on measured variations in temperature.

24. The system of claim 22 wherein the first predefined value is modified based on a difference in time between a first clock operated, at least indirectly, from the modified pulse stream and a second clock that does not operate from the modified pulse stream.

25. The system of claim 24 wherein the first predefined value is modified based on, at least in part, a current value of the first predefined value and on a difference in lapsed time between at least two readings from the second clock.

26. The system of claim 25 wherein the circuitry and first clock are part of the communication device and the modified pulse stream operates with the communication device and wherein the second clock operates within the medical device.

27. The system of claim 1 wherein the initial frequency is derived from an oscillator that operates at a higher frequency.

28. The system of claim 1 wherein the initial frequency is the highest oscillator frequency produced by the oscillator circuit.

29. A medical system, comprising:

a) an ambulatory medical device (MD) comprising MD electronic control circuitry that further comprises at least one MD telemetry system and at least one MD processor that controls, at least in part, operation of the MD telemetry system and operation of the medical device, wherein the medical device is configured to provide a treatment to a body of a patient or to monitor a selected state of the body; and

b) a communication device (CD) comprising CD electronic control circuitry that further comprises at least one CD telemetry system and at least one CD processor that controls, at least in part, operation of the CD telemetry system and operation of the communication device, wherein the CD telemetry system sends messages to or receives messages from the MD telemetry system,

wherein the communication device further comprises a CD timing module, a CD crystal oscillator, and at least one CD temperature transducer,

wherein the CD timing module uses at least the CD temperature transducer in combination with known properties of the CD crystal oscillator to modify a rate of tracking of time by the CD timing module.

30. The system of claim 29 wherein a first portion of the MD telemetry system is incorporated into the MD processor and a second portion of the MD telemetry system is external to the MD processor, or wherein a first portion of the CD telemetry system is incorporated into the CD processor and a second portion of the CD telemetry system is external to the CD processor.

31. The system of claim 30 wherein (1) the MD electronic control circuitry comprises at least one external MD functional module, other than the second portion of the MD telemetry system, that is external to the MD processor, (2) the CD electronic control circuitry comprises at least one external CD functional module, other than the second portion of the CD telemetry system, that is external to the CD processor, (3) the MD processor comprises an internal MD CPU and at least one other internal MD functional module, or (4) the CD processor comprises an internal CD CPU and at least one other internal CD functional module.

32. The system of claim 29 wherein the modified time is used in transmitting messages to the medical device.

33. The system of claim 29 wherein the medical device listens only part of the time for incoming messages from the CD telemetry system or transmits unsolicited messages to the communication device only at selected times, wherein the communication device estimates the medical device'"'"'s inbound listening times or potential outbound transmission times based, at least in part, upon at least one temperature measurement made since a last message was exchanged between with the medical device and the communication device in combination with known variations in crystal oscillation frequency with temperature.

34. The system of claim 33 wherein temperature measurements occur and adjustments to the medical device'"'"'s inbound listening times or potential outbound transmission times occur on a periodic basis.

35. The system of claim 29 wherein the medical device comprises at least one of (1) an implantable infusion pump for selectively dispensing a selected drug, (2) an implantable infusion pump for selectively dispensing insulin, (3) an implantable sensor for sensing a selected state of the body, (4) an implantable sensor for sensing glucose level, or (5) an implantable electrode for selectively stimulating a portion of the body of the patient.

36. A medical system, comprising:

a) an ambulatory medical device (MD) comprising MD electronic control circuitry that further comprises at least one MD telemetry system and at least one MD processor that controls, at least in part, operation of the MD telemetry system and operation of the medical device, wherein the medical device is configured to provide a treatment to a body of a patient or to monitor a selected state of the body; and

b) a communication device (CD) comprising CD electronic control circuitry that further comprises at least one CD telemetry system and at least one CD processor that controls, at least in part, operation of the CD telemetry system and operation of the communication device, wherein the CD telemetry system sends messages to or receives messages from the MD telemetry system,

wherein the medical device further comprises an MD timing module, an MD crystal oscillator, and at least one MD temperature transducer,

wherein the MD timing module uses at least the MD temperature transducer in combination with known properties of the MD crystal oscillator to modify a rate of tracking of time by the MD timing module.

37. The system of claim 36 wherein a first portion of the MD telemetry system is incorporated into the MD processor and a second portion of the MD telemetry system is external to the MD processor, or wherein a first portion of the CD telemetry system is incorporated into the CD processor and a second portion of the CD telemetry system is external to the CD processor.

38. The system of claim 37 wherein (1) the MD electronic control circuitry comprises at least one external MD functional module, other than the second portion of the MD telemetry system, that is external to the MD processor, (2) the CD electronic control circuitry comprises at least one external CD functional module, other than the second portion of the CD telemetry system, that is external to the CD processor, (3) the MD processor comprises an internal MD CPU and at least one other internal MD functional module, or (4) the CD processor comprises an internal CD CPU and at least one other internal CD functional module.

39. The system of claim 36 wherein the medical device comprises at least one of (1) an implantable infusion pump for selectively dispensing a selected drug, (2) an implantable infusion pump for selectively dispensing insulin, (3) an implantable sensor for sensing a selected state of the body, (4) an implantable sensor for sensing glucose level, or (5) an implantable electrode for selectively stimulating a portion of the body of the patient.