Devices and methods for passive patient monitoring

• US 20040111045A1
• Filed: 11/20/2002
• Published: 06/10/2004
• Est. Priority Date: 11/20/2002
• Status: Active Grant

• Current Assignee: Hoana Medical, Inc.
• Original Assignee: Hoana Technologies Incorporated
• Inventors: Cheung, Ken C.K., Sullivan, Christopher J., Pernambuco-Wise, Paul, Christensen, Scott, Rosenman, Mike, Sullivan, Patrick K.
• Granted Patent: US 7,666,151 B2
• Time in Patent Office: Days
• US Class Current: 600/595
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 2562/043 in a linear array
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 2562/225 Connectors or couplings
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/1126 using a particular sensing technique
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/4833 Assessment of subject's compliance to treatment
• CPC Class Codes: A61B 5/6887 mounted on external non-worn devices, e.g. non-medical devices
• CPC Class Codes: A61B 5/6891 Furniture
• CPC Class Codes: A61B 5/6892 Mats

Abstract

Devices, systems and methods provide passive patient monitoring of such parameters as body motion, body position, respiratory rate and/or heart rate. Passive monitoring generally involves a sensor device having at least two piezoelectric sensors, provided on a surface, such as a bed, chair, operating table or the like, so that a patient may be coupled with the device by simply allowing the patient to lie, sit, lean, stand on or wear the surface. In one embodiment, multiple patients in a general care area of a hospital may be continuously monitored via multiple passive monitoring devices. If a patient fails to meet one or more predefined threshold criteria or has a negative physiological trend, the system may activate an alarm.

Claims

1. A method of passively monitoring at least one patient, the method comprising:

providing a sensor device on a surface, the sensor device having at least two piezoelectric sensors;

coupling a patient with at least a portion of the sensor device by allowing the patient to lie, sit, lean, stand on or wear the surface;

sensing a first mechanical signal with a first piezoelectric sensor of the sensor device;

sensing a second mechanical signal with a second piezoelectric sensor of the sensor device;

converting the first and second mechanical signals into first and second digital signals;

comparing the first and second digital signals; and

providing patient data to a user based on the comparison of the digital signals.

2. A method as in claim 1, wherein the sensor device is provided on a surface selected from the group consisting of a hospital bed, a bed, an operating room table, an examining table, a procedure chair or table, a dentist'"'"'s chair, a hospital chair, a chair seat, a chair back, a wheelchair, a baby'"'"'s crib, a stretcher and a gurney.

3. A method as in claim 1, wherein the sensor device further comprises a flat surface having means for coupling the at least two piezoelectric sensors with the flat surface.

4. A method as in claim 1, wherein coupling the patient with the sensor device comprises allowing the patient to lie on a bed on which the device is provided.

5. A method as in claim 1, wherein coupling the patient with the sensor device comprises allowing the patient to sit on a chair on which the device is provided.

6. A method as in claim 1, wherein coupling comprises coupling the patient with the sensor through at least one layer of clothing, bedding or other material.

7. A method as in claim 1, wherein sensing the first and second mechanical signals comprises sensing at least one of a stress signal, a thermal signal and an acoustic signal.

8. A method as in claim 1, wherein sensing the first and second mechanical signals comprises sensing the signals in a patient in a general care area of a hospital, in a long-term care facility or in a nursing home.

9. A method as in claim 1, wherein sensing the first and second mechanical signals comprises sensing the signals in a patient undergoing a surgical procedure under conscious sedation.

10. A method as in claim 1, further comprising:

sensing third and fourth mechanical signals with third and fourth piezoelectric sensors;

converting the third and fourth mechanical signals into third and fourth digital signals; and

comparing the first, second, third and fourth digital signals.

11. A method as in claim 1, wherein comparing the digital signals comprises comparing presence or absence of the first signal with presence or absence of the second signal.

12. A method as in claim 11, wherein comparing the digital signals further comprises comparing quality of the first signal with quality of the second signal.

13. A method as in claim 12, further including selecting either the first signal or the second signal to provide as data to a user, based on which of the signals has the best quality.

14. A method as in claim 11, further comprising determining, based on the comparison of the first signal with the second signal, presence or absence of the patient on the surface.

15. A method as in claim 14, further comprising determining a position of the patient on the surface.

16. A method as in claim 1, further comprising grouping the digital signals into at least two groups corresponding to at least two patient parameters.

17. A method as in claim 16, wherein the at least two parameters are selected from the group consisting of patient motion on the sensor device, patient position on the sensor device, patient respiratory rate and patient heart rate.

18. A method as in claim 1, further comprising comparing at least one of the digital signals to at least one predefined threshold.

19. A method as in claim 18, wherein comparing at least one of the digital signals to the predefined threshold comprises comparing at least one body motion digital signal with at least one of a minimum amount of body motion and a maximum amount of body motion.

20. A method as in claim 18, wherein comparing at least one of the digital signals to the predefined threshold comprises comparing a respiratory rate digital signal with at least one of a minimum respiratory rate and a maximum respiratory rate.

21. A method as in claim 18, wherein comparing at least one of the digital signals to the predefined threshold comprises comparing a heart rate digital signal with at least one of a minimum heart rate and a maximum heart rate.

22. A method as in claim 18, wherein providing patient data to a user comprises activating an alarm when the at least one digital signal does not meet the at least one predefined threshold.

23. A method as in claim 1, further comprising:

comparing at least one of the digital signals to a least one earlier digital signal; and

recognizing a trend in a patient parameter based on the comparison of the digital signal to the earlier digital signal.

24. A method as in claim 23, further comprising activating alarm when the trend in the patient parameter matches a predefined negative trend.

25. A method as in claim 24, wherein comparing at least one of the digital signals comprises:

comparing at least one heart beat signal to at least one earlier heart beat signal; and

comparing at least one respiratory signal to at least one earlier respiratory signal;

wherein the negative trend comprises a combination of a negative heart beat trend and a negative respiratory trend.

26. A method as in claim 1, wherein providing patient data to a user comprises activating an alarm based on the comparison of the digital signals.

27. A method as in claim 26, wherein providing patient data to a user further comprises providing a position of the patient on the surface.

28. A method as in claim 26, wherein providing patient data to a user further comprises providing a respiratory rate of the patient.

29. A method as in claim 26, wherein providing patient data to a user further comprises providing a heart rate of the patient.

30. A method as in claim 1, wherein the at least one patient comprises multiple patients and wherein providing patient data comprises providing data at a common location.

31. A method as in claim 30, wherein the multiple patients comprise multiple patients in a general care area of a hospital, in a long-term care facility or in a nursing home.

32. A method as in claim 30, wherein the common location is selected from the group consisting of a nursing station, a display monitor, a digital pager, a wireless handheld device, a call station and a monitoring room.

33. A method of passively monitoring physiology of multiple patients, the method comprising:

providing multiple sensor devices on multiple surfaces, each sensor device having at least two piezoelectric sensors;

coupling each of the patients with at least a portion of one of the sensor devices by allowing each patient to lie, sit, lean, stand on or wear one of the surfaces;

sensing at least one mechanical signal with at least two of the piezoelectric sensors on each sensor device;

converting sensed mechanical signals into digital signals;

comparing digital signals corresponding to at least two of the piezoelectric sensors for each patient; and

providing patient data corresponding to the multiple patients to a user at a central location, based on the comparison of the digital signals.

34. Apparatus for passively monitoring a patient, the apparatus comprising:

a surface for coupling with the patient;

at least two piezoelectric sensors coupled with the surface for sensing at least one mechanical signal from the patient;

a processor coupled with the piezoelectric sensors for converting the at least one mechanical signal into at least one digital signal and for comparing digital signals corresponding to the at least two piezoelectric sensors to provide data pertaining to the patient;

at least a first connector for coupling the piezoelectric sensors with the processor; and

at least a second connector for coupling the processor with apparatus for providing the patient data to a user.

35. Apparatus as in claim 34, wherein the surface comprises a flat pad.

36. Apparatus as in claim 35, wherein the flat pad comprises at least one layer of a resilient foam material.

37. Apparatus as in claim 34, wherein the piezoelectric sensors are disposed along the surface in a pattern to facilitate monitoring of at least one of patient body position, patient movement, patient respiratory rate and patient heart rate.

38. Apparatus as in claim 37, wherein the pattern comprises two or more adjacent, flat piezoelectric sensors.

39. Apparatus as in claim 38, wherein the pattern comprises a grid pattern comprising at least two adjacent rows and at least two columns of piezoelectric sensors.

40. Apparatus as in claim 34, wherein dimensions of the surface allow the surface to be positioned on at least one of a crib and a bed for monitoring an infant.

41. Apparatus as in claim 34, wherein dimensions of the surface allow the surface to be positioned on a bed for monitoring a patient in a hospital, long-term care facility or nursing home.

42. Apparatus as in claim 34, wherein dimensions of the surface allow the surface to be positioned on a chair for monitoring a patient undergoing a procedure under conscious sedation.

43. Apparatus as in claim 34, further comprising a sheath for containing at least a portion of the surface to provide a protective layer between the surface and the patient.

44. Apparatus as in claim 43, wherein the sheath is water resistant.

45. Apparatus as in claim 43, wherein the sheath includes at least one sheath-surface connector, and wherein the surface must be connected with the sheath via the sheath-surface connector in order to monitor the at least one mechanical signal of the patient.

46. Apparatus as in claim 43, wherein the sheath is disposable after being used to monitor one patient.

47. Apparatus as in claim 34, wherein the piezoelectric sensors are selected from the group consisting of polyvinylidene fluoride film, polyvinylidene fluoride cable, piezoelectric ceramic discs and piezoelectric foam.

48. Apparatus as in claim 34, wherein the surface is provided on a flat surface of a bed, and wherein the at least one mechanical signal of the patient may be monitored when the patient lies on the surface.

49. Apparatus as in claim 34, wherein the at least one mechanical signal comprises at least one of a stress signal, a thermal signal and an acoustic signal.

50. Apparatus as in claim 34, wherein the first connector comprises means for detecting at least one of a type of sensor device coupled with the processor and a number of times the sensor device has been used.

51. Apparatus as in claim 50, wherein the first connector further comprises means for activating the sensor device.

52. Apparatus as in claim 34, wherein at least one of the first connector and the second connector comprises a wireless transmitter.

53. Apparatus as in claim 34, wherein the processor provides the patient data by activating an alarm.

54. Apparatus as in claim 53, wherein the processor activates the alarm if the comparison of the digital signals suggests that the patient is not moving on the surface, the patient is not in contact with the surface, or the patient is moving excessively on the surface.

55. Apparatus as in claim 53, wherein the processor activates the alarm if a respiratory rate of the patient falls below a predefined minimum respiratory rate or rises above a predefined maximum respiratory rate.

56. Apparatus as in claim 53, wherein the processor activates the alarm if a heart rate of the patient falls below a predefined minimum heart rate or rises above a predefined maximum heart rate.

57. Apparatus as in claim 53, wherein the processor further provides the patient data in the form of a patient respiratory rate.

58. Apparatus as in claim 53, wherein the processor further provides the patient data in the form of a patient heart rate.

59. Apparatus as in claim 53, wherein the processor further provides the patient data in the form of a patient position on the surface.

60. A disposable sheath for containing at least a portion of a sensor device for passively monitoring a patient, the sheath comprising:

a flat surface for coupling with the patient; and

at least one housing for containing at least a portion of the sensor device.

61. A disposable sheath as in claim 60, wherein the sheath is water resistant.

62. A disposable sheath as in claim 60, further including at least one connector for removably connecting the sheath with the apparatus for passively monitoring physiology, wherein connecting the sheath to the apparatus allows the apparatus to be activated to monitor the physiology of the patient.

63. A system for passively monitoring multiple patients, the system comprising:

a plurality of sensor devices, each sensor device comprising;

a surface for coupling with the patient; and

at least two piezoelectric sensors coupled with the surface for sensing at least one mechanical signal from a patient;

a plurality of processors, each processor coupled with one sensor device for converting the at least one mechanical signal into at least one digital signal and for comparing digital signals corresponding to each of the at least two piezoelectric sensors to provide data pertaining to the patient; and

at least one connector coupled with each processor for connecting each processor with a common apparatus for providing the patient data for the multiple patients to a user.

64. A system as in claim 63, wherein the surface comprises a flat pad.

65. A system as in claim 64, wherein the flat pad comprises at least one layer of a resilient foam material.

66. A system as in claim 63, wherein the piezoelectric sensors are disposed along the surface in a pattern to facilitate monitoring of at least one of patient body position, patient movement, patient respiratory rate and patient heart rate.

67. A system as in claim 66, wherein the pattern comprises two or more adjacent, flat piezoelectric sensors.

68. A system as in claim 67, wherein the pattern comprises a grid pattern comprising at least two adjacent rows and at least two columns of piezoelectric sensors.

69. A system as in claim 63, wherein dimensions of the surface allow the surface to be positioned on at least one of a crib and a bed for monitoring an infant.

70. A system as in claim 63, wherein dimensions of the surface allow the surface to be positioned on a bed for monitoring a patient in a hospital, long-term care facility or nursing home.

71. A system as in claim 63, wherein dimensions of the surface allow the surface to be positioned on a chair for monitoring a patient undergoing a procedure under conscious sedation.

72. A system as in claim 63, further comprising a sheath for containing at least a portion of the surface to provide a protective layer between the surface and the patient.

73. A system as in claim 72, wherein the sheath is water resistant.

74. A system as in claim 72, wherein the sheath includes at least one sheath-surface connector, and wherein the surface must be connected with the sheath via the sheath-surface connector in order to monitor the at least one mechanical signal of the patient.

75. A system as in claim 72, wherein the sheath is disposable after being used to monitor one patient.

76. A system as in claim 63, wherein the piezoelectric sensors are selected from the group consisting of polyvinylidene fluoride film, polyvinylidene fluoride cable, piezoelectric ceramic discs and piezoelectric foam.

77. A system as in claim 63, wherein the surface is provided on a flat surface of a bed, and wherein the at least one mechanical signal of the patient may be monitored when the patient lies on the surface.

78. A system as in claim 63, wherein the at least one mechanical signal comprises at least one of a stress signal, a thermal signal and an acoustic signal.

79. A system as in claim 63, wherein each of the sensor devices is coupled with one of the processors via a wireless connection.

80. A system as in claim 63, wherein the at least one connector connects each of the processors to at least one of a common alarm, a common display device, at least one digital pager, at least one handheld wireless device, an Ethernet connection, an Internet connection and an intranet connection.

81. A system as in claim 63, wherein each of the plurality of processors provides the patient data by activating an alarm.

82. A system as in claim 81, wherein each of the plurality of processors activates the alarm if the comparison of the digital signals suggests that the patient is not moving on the surface, the patient is not in contact with the surface, or the patient is moving excessively on the surface.

83. A system as in claim 81, wherein each of the plurality of processors activates the alarm if a respiratory rate of the patient falls below a predefined minimum respiratory rate or rises above a predefined maximum respiratory rate.

84. A system as in claim 81, wherein each of the plurality of processors activates the alarm if a heart rate of the patient falls below a predefined minimum heart rate or rises above a predefined maximum heart rate.

85. A system as in claim 81, wherein each of the plurality of processors further provides the patient data in the form of a patient respiratory rate.

86. A system as in claim 81, wherein each of the plurality of processors further provides the patient data in the form of a patient heart rate.

87. A system as in claim 81, wherein each of the plurality of processors further provides the patient data in the form of a patient position on the surface.