Cellular architecture and data transfer methods for real time patient monitoring within medical facilities

• US 6,773,396 B2
• Filed: 01/24/2001
• Issued: 08/10/2004
• Est. Priority Date: 11/13/1995
• Status: Expired due to Term

• Current Assignee: GE Medical Systems Information Technologies Incorporated (GE Healthcare Technologies, Inc.)
• Original Assignee: GE Medical Systems Information Technologies Incorporated (GE Healthcare Technologies, Inc.)
• Inventors: Flach, Terry E., Stoop, Michael D.
• Primary Examiner(s): Jones, Mary Beth
• Assistant Examiner(s): ASTORINO, MICHAEL C
• Application Number:
  US09/769,233
• Publication Number:
  US 20010023315A1
• Time in Patent Office: 1,294 Days
• Field of Search: 600/300-301, 128/903-904, 128/920, 340/870.1, 340/573.1, 709/200, 705/1-4, 370/347, 370/349
• US Class Current: 600/300
• CPC Class Codes: A61B 2560/0209 adapted for power saving
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/002 Monitoring the patient using a local or closed circuit, e.g. in a room or building A61B5/0017 takes precedence
• CPC Class Codes: A61B 5/1113 Local tracking of patients, e.g. in a hospital or private home
• CPC Class Codes: H03L 3/00 Starting of generators
• CPC Class Codes: H03L 7/10 for assuring initial synchronisation or for broadening the capture range
• CPC Class Codes: H03L 7/14 for assuring constant frequency when supply or correction voltages fail or are interrupted
• CPC Class Codes: H04B 1/1615 Switching on; Switching off, e.g. remotely battery saving circuits associated with selective call operation H04W52/00; details of power consumption reduction in a PLL, H03L7/0802, H03L7/14, H03L2207/08, H03L2207/18; muting amplifiers by gain control see H03G3/34
• CPC Class Codes: H04W 52/028 switching on or off only a part of the equipment circuit blocks
• CPC Class Codes: Y02D 30/70 in wireless communication networks
• CPC Class Codes: Y10S 128/903 Radio telemetry
• CPC Class Codes: Y10S 128/904 Telephone telemetry

Abstract

A real time patient monitoring system uses a cellular architecture to monitor ECG signals and other physiologic data of patients, including ambulatory patients. The system includes wireless telemeters that attach to and transmit the physiologic data of respective patients. The telemeters communicate bi-directionally with ceiling-mounted RF transceivers, referred to as “VCELLs,” using a wireless TDMA protocol. The VCELLs forward packets of physiologic data received from the telemeters to patient monitoring stations on a LAN. The VCELLs are spatially distributed throughout the medical facility to provide multiple cells or zones of coverage. As a patient moves throughout the medical facility, the patient'"'"'s telemeter connects to, and disconnects from, specific VCELLs to maintain connectivity to the LAN. The telemeters and VCELLs also implement a patient location tracking process for monitoring of the locations of individual patients.

Claims

1. A method by which a remote telemeter operates to convey real time physiologic data of a patient by wireless communications, the method comprising:

receiving the real time physiologic data of the patient;

evaluating wireless links to each of a plurality of RF transceivers that are spatially distributed within a medical facility and coupled to a network;

connecting to, and disconnecting from, individual RF transceivers of the plurality in response to changes in qualities of the wireless links, such that connectivity to the network is generally maintained; and

transmitting packets of the real time physiologic data to an RF transceiver with which a connection is currently established;

whereby the remote telemeter permits the patient'"'"'s physiologic data to be monitored on the network as the patient moves into and out of range of specific RF transceivers.

2. The method as in claim 1, wherein the remote telemeter receives the physiologic data directly from a lead set that attaches to the patient.

3. The method as in claim 1, wherein the remote telemeter receives the physiologic data from a bedside monitor.

4. The method as in claim 1, wherein the remote telemeter assesses the wireless links at least by switching between wireless channels to which the RF transceivers are assigned, and receiving and assessing qualities of transmissions on such wireless channels.

5. The method as in claim 4, wherein the remote telemeter maintains a history of wireless link assessments within a memory, and uses the history to select RF transceivers with which to establish connections.

6. The method as in claim 1, wherein the remote telemeter communicates with the RF transceivers using a wireless time division multiple access (TDMA) protocol.

7. The method as in claim 1, wherein the method comprises maintaining connections with, and transmitting packets of physiologic data to, two RF transceivers at a time.

8. A remote telemeter which operates according to the method of claim 1.

9. A medical telemetry system, comprising:

a plurality of radio frequency (RF) transceiver units connected to a wired computer network to provide wireless access points to the wired computer network, the RF transceiver units spatially distributed throughout patient areas of a medical facility to provide multiple coverage zones for monitoring patients; and

a plurality of telemeters that receive at least electrocardiograph (ECG) signals of respective patients, and transmit the ECG signals by wireless communications to the wired computer network via the plurality of RF transceiver units to allow the ECG signals to be monitored substantially in real time on the wired computer network;

wherein the telemeters and the RE transceiver units implement a communications protocol in which an RF transceiver unit used to convey a patient'"'"'s ECG signals to the wired computer network is selected dynamically based on assessments of wireless link conditions between the patient'"'"'s telemeter and specific RE transceiver units, whereby general connectivity is maintained between the telemeter and the wired computer network as the patient moves throughout the multiple coverage zones.

10. The medical telemetry system as in claim 9, wherein at least some of the plurality of RF transceiver units are mounted to a ceiling of the medical facility.

11. The medical telemetry system as in claim 9, wherein the telemeters and the RF transceiver units communicate using a time division multiple access (TDMA) protocol in which ECG signal data of multiple patients is transmitted to an RF transceiver unit during a TDMA frame of that RF transceiver unit.

12. The medical telemetry system as in claim 11, wherein the RF transceiver unit broadcasts timeslot availability messages to the telemeters during a portion of the TDMA frame.

13. The medical telemetry system as in claim 9, wherein the communications protocol provides a combination of space, time, and frequency diversity for transmissions of ECG signal data from the telemeters to the wired computer network.

14. The medical telemetry system as in claim 9, wherein at least one of the telemeters attempts to maintain wireless connections with at least two of the RF transceiver units at a time to provide redundant transmission paths for conveying a patient'"'"'s ECG signal data to the wired computer network.

15. The medical telemetry system as in claim 9, wherein each RF transceiver unit operates on one of multiple wireless channels, and the telemeters switch between the multiple wireless channels to switch between RF transceiver units.

16. The medical telemetry system as in claim 15, wherein at least two of the RF transceiver units that are spaced apart from each other by more than a predefined distance operate on a common channel of the multiple wireless channels to provide frequency reuse.

17. The medical telemetry system as in claim 15, wherein each telemeter monitors the multiples wireless channels to make said assessments of wireless link conditions, and uses the assessments to select specific RF transceiver units with which to communicate.

18. The medical telemetry system as in claim 9, wherein the assessments of wireless link-conditions are made by the telemeters.

19. The medical telemetry system as in claim 9, wherein the telemeters further sense and transmit at least one type of physiologic data other than ECG signal data.

20. The medical telemetry system as in claim 9, further comprising at least one instrument telemeter which is adapted to connect to a bedside monitor of a patient, and to transmit physiologic data received from the bedside monitor to the wired computer network via at least one of the RF transceiver units.

21. The medical telemetry system as in claim 9, wherein at least one of the RF transceiver units is positioned within an X-ray room, a computerized axial tomography (CAT) scanning room, or a fluoroscopy room, to permit monitoring of patients near known intermittent sources of interference.

22. The medical telemetry system as in claim 9, wherein the telemeters and the RF transceiver units implement a patient location tracking algorithm for determining respective locations of patients.

23. The medical telemetry system as in claim 9, wherein the wired computer network comprises a local area network (LAN) of the medical facility.

24. The medical telemetry system as in claim 23, further comprising a plurality of monitoring stations connected to the LAN, each monitoring station configured to display the ECG signal data of the patients.

25. The medical telemetry system as in claim 23, further comprising a gateway which connects the LAN to the Internet to permit exchanges of patient data with other medical facilities.

26. The medical telemetry system as in claim 9, wherein at least some of the plurality of telemeters are ambulatory telemeters.

27. The medical telemetry system as in claim 9, wherein at least some of the plurality of telemeters are instrument telemeters.

28. A patient monitoring system, comprising:

a plurality of radio frequency (RF) transceiver units connected to a computer network to provide wireless access to the computer network, the RF transceiver units spatially distributed throughout patient areas of a medical facility to provide multiple coverage zones; and

a plurality of telemeters that receive at least electrocardiograph (ECG) waveform data of respective patients, and transmit the ECG waveform data by wireless communications to the computer network via the plurality of RF transceiver units to allow the ECG waveform data to be monitored substantially in real time on the computer network;

wherein the telemeters and the RF transceiver units implement a switch-over protocol in which a telemeter of a patient connects to and disconnects from specific RF transceiver units of the plurality to maintain general connectivity to the computer network as the patient moves across the multiple coverage zones.

29. The patient monitoring system as in claim 28, wherein at least some of the plurality of RF transceiver units are mounted to a ceiling of the medical facility.

30. The patient monitoring system as in claim 28, wherein the telemeters and the RF transceiver units communicate using a time division multiple access (TDMA) protocol in which the ECG waveform data of multiple patients is transmitted to an RF transceiver unit during a TDMA frame of that RF transceiver unit.

31. The patient monitoring system as in claim 30, wherein the RF transceiver unit broadcasts timeslot availability messages to the telemeters during a portion of the TDMA frame.

32. The patient monitoring system as in claim 28, wherein the telemeters transmit at least the ECG waveform data to the RF transceiver units according to a communications protocol that provides a combination of space, time, and frequency diversity.

33. The patient monitoring system as in claim 28, wherein at least one of the telemeters attempts to maintain wireless connections with at least two of the RF transceiver units at a time to provide redundant transmission paths for conveying a patient'"'"'s ECG waveform data to the computer network.

34. The patient monitoring system as in claim 28, wherein each RF transceiver unit operates on one of multiple wireless channels, and the telemeters switch between the multiple wireless channels to switch between RF transceiver units.

35. The patient monitoring system as in claim 34, wherein at least two of the RF transceiver units that are spaced apart from each other by more than a predefined distance operate on a common channel of the multiple wireless channels to provide frequency reuse.

36. The patient monitoring system as in claim 34, wherein each telemeter monitors the multiple wireless channels to make assessments of wireless link conditions offered by specific RF transceiver units, and uses the assessments to select RF transceiver units with which to establish connections.

37. The patient monitoring system as in claim 28, wherein each RF transceiver unit is capable of maintaining wireless connections with multiple telemeters at a time.

38. The patient monitoring system as in claim 28, wherein the telemeters further sense and transmit at least one type of physiologic data other than ECG waveform data.

39. The patient monitoring system as in claim 28, wherein at least some of the telemeters are instrument telemeters that receive the ECG waveform data from bedside monitors.

40. The patient monitoring system as in claim 28, wherein at least one of the RF transceiver units is positioned within an X-ray room, a computerized axial tomography (CAT) scanning room, or a fluoroscopy room, to permit monitoring of patients near known intermittent sources of interference.

41. The patient monitoring system as in claim 28, wherein the telemeters and the RF transceiver units implement a patient location tracking algorithm for monitoring current locations of patients.

42. The patient monitoring system as in claim 28, wherein the computer network comprises a local area network (LAN) of the medical facility.

43. The patient monitoring system as in claim 42, further comprising a plurality of monitoring stations connected to the LAN, each monitoring station configured to display the ECG waveform data of the patients.

44. The patient monitoring system as in claim 42, further comprising a gateway which connects the LAN to the Internet to permit exchanges of patient data with other medical facilities.

45. A method of conveying real-time electrocardiograph (ECG) waveform data of a patient from a telemeter coupled to the patient to a wired computer network, comprising, with the telemeter:

(a) continuously receiving and packetizing the ECG waveform data of the patient;

(b) monitoring transmissions from RF transceiver units on each of multiple wireless communications channels, and based on assessments of the transmissions, selecting an RF transceiver unit with which to establish a wireless connection, wherein the RF transceiver units are spatially distributed throughout at least a portion of a medical facility, and are configured to forward data received from telemeters to the wired computer network;

(c) establishing a wireless connection with the RF transceiver unit selected in (b);

(d) repeating (b) and (c) to maintain general connectivity to the wired network as the patient moves into and out of range of specific RF transceiver units within said portion of the medical facility; and

(e) transmitting packets of the ECG waveform data to at least one RF transceiver unit with which a wireless connection is currently established to permit the ECG waveform data to be monitored continuously and in real time on the wired computer network.

46. The method as in claim 45, wherein (b) and (c) are performed so as to attempt to maintain wireless connections with multiple RF transceiver units at a time, and wherein (e) comprises transmitting like ECG waveform data to the multiple RF transceiver units to provide redundant transmission paths.

47. The method as in claim 45, wherein (c) comprises transmitting a timeslot request message to the selected RF transceiver unit.

48. A telemeter which operates according to the method of claim 45.

49. A plurality of radio frequency (RF) transceiver units positioned throughout multiple patent areas of a medical facility, including patient areas that are remote from one another, to provide wireless access to a wired computer network on which physiologic data of patients is monitored substantially in real time, each RF transceiver unit comprising a processor which executes a control program to implement a time division multiple access (TDMA) protocol in which an RF transceiver unit maintains wireless connections with multiple patient telemeters at a time, and forwards packets received from the multiple telemeters to the wired computer network to permit real time monitoring of physiologic data contained therein, the control program supporting the ability for the patient telemeters to establish and discontinue wireless connections with specific RF transceiver units of the plurality over time such that connectivity between a patient telemeter and the wired computer network is generally maintained as the telemeter is moved throughout said multiple patient areas.

50. The plurality of RF transceiver units as in claim 49, wherein at least some of the RF transceiver units are mounted to a ceiling of the medical facility.

51. The plurality of RF transceiver units as in claim 49, wherein at least one of the plurality of RF transceiver units is positioned within an X-ray room, a computerized axial tomography (CAT) scanning room, or a fluoroscopy room, to permit monitoring of patients near known intermittent sources of interference.

52. The plurality of RF transceiver units as in claim 49, wherein at least two of the RF transceiver units that are spaced apart from each other by more than a predefined distance operate on a common wireless channel to provide frequency reuse.

53. The plurality of RF transceiver units as in claim 49, wherein each RF transceiver unit broadcasts timeslot availability messages during a predefined portion of a TDMA frame.

54. The plurality of RF transceiver units as in claim 49, wherein the RF transceiver units implement a patient location tracking algorithm for determining respective locations of patients.

55. The plurality of RF transceiver units as in claim 49, in combination with a plurality of said patient telemeters.

56. The plurality of RF transceiver units as in claim 55, wherein at least some of the plurality of patient telemeters are adapted to be worn by a patient while ambulatory.

57. The plurality of RF transceiver units as in claim 55, wherein at least one of the patient telemeters is configured to maintain wireless connections with two of the RF transceiver units at a time to provide redundant transmission paths for transmissions of a patient'"'"'s physiologic data.

58. The plurality of RF transceiver units as in claim 49, in combination with a plurality of patient monitoring stations which receive and process the physiologic data over the wired computer network.

59. The plurality of RF transceiver units as in claim 58, in further combination with the wired computer network.

60. A radio frequency (RF) transceiver adapted to be mounted to a ceiling within a patient area of a medical facility to provide wireless access to a computer network on which physiologic data of patients is monitored substantially in real time, the RF transceiver comprising a processor programmed to implement a time division multiple access (TDMA) protocol in which the RF transceiver maintains wireless connections with multiple patient telemeters at a time, and forwards packetized physiologic data received from the multiple telemeters to a processing node of the computer network substantially in real time, the processor further programmed to establish and discontinue wireless connections with the patient telemeters to support patient mobility within the medical facility into and out of range of the RF transceiver.

61. The RF transceiver as in claim 60, wherein the processor is further programmed to broadcast timeslot availability messages during a predefined portion of a TDMA frame.

62. The RF transceiver as in claim 60, wherein the processor is further programmed to implement a patient location tracking method.