CONTROLLING OPERATION OF A REDUCED PRESSURE THERAPY SYSTEM BASED ON DYNAMIC DUTY CYCLE THRESHOLD DETERMINATION

• US 20150051560A1
• Filed: 03/13/2013
• Published: 02/19/2015
• Est. Priority Date: 03/20/2012
• Status: Active Grant

• Current Assignee: Smith & Nephew PLC
• Original Assignee: Smith & Nephew PLC
• Inventors: Askem, Ben Alan
• Granted Patent: US 9,901,664 B2
• Time in Patent Office: Days
• US Class Current: 604/319
• CPC Class Codes: A61M 1/74 Suction control underwater drainage A61M1/61
• CPC Class Codes: A61M 1/75 Intermittent or pulsating suction A61M1/63, A61M1/772 take precedence
• CPC Class Codes: A61M 1/96 Suction control thereof
• CPC Class Codes: A61M 1/985 the dressing itself forming the collection container
• CPC Class Codes: A61M 2205/15 Detection of leaks
• CPC Class Codes: A61M 2205/276 preventing unwanted use
• CPC Class Codes: A61M 2209/088 on the body
• CPC Class Codes: H02M 1/0003 Details of control, feedback or regulation circuits
• CPC Class Codes: H02M 1/0012 Control circuits using digital or numerical techniques in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873

Abstract

Negative pressure wound therapy apparatuses and dressings, and systems and methods for operating such apparatuses for use with dressings are disclosed. In some embodiments, controlling the delivery of therapy can be based on monitoring and detecting various operating conditions. An apparatus can have a controller configured to monitor a duty cycle of a source of negative pressure. Based on the monitored duty cycle, the controller can determine whether a leak is present and provide an indication to a user. The controller can determine a duty cycle threshold in order to achieve an optimal or near optimal balance between an uninterrupted delivery of therapy, avoidance inconveniencing a user, conserving power, achieving optimal or near optimal efficiency, and/or limiting vibrational noise. In some embodiments, the duty cycle threshold is determined based at least in part on a capacity of a power source and an operational time of the apparatus.

Claims

1-44. -44. (canceled)

45. An apparatus for applying negative pressure to a wound, comprising:

a negative pressure source configured to be fluidically coupled to a wound dressing;

a power source configured to supply power to the apparatus; and

a controller configured to;

monitor a duty cycle of the negative pressure source, an operational time of the apparatus elapsed from an initial activation of the apparatus, and a remaining capacity of the power source;

determine a duty cycle threshold based at least in part on the remaining capacity of the power source and the operational time of the apparatus; and

operate the negative pressure source based at least in part on the determined duty cycle threshold.

46. The apparatus of claim 45, wherein the controller is further configured to:

activate the negative pressure source; and

provide an indication in response to determining that the duty cycle has exceeded the duty cycle threshold.

47. The apparatus of claim 45, wherein the indication comprises deactivating the negative pressure source.

48. The apparatus of claim 45, wherein the duty cycle reflects an amount of time the negative pressure source is active over a period of time.

49. The apparatus of claim 45, wherein the controller is configured to determine the duty cycle threshold according to at least one of a quadratic function and a linear function.

50. The apparatus of claim 45, wherein the controller is further configured to:

determine the operational time based on a total elapsed time since the initial activation of the apparatus; and

disable activation of the negative pressure source when the operational time reaches a lifetime threshold.

51. The apparatus of claim 50, wherein the lifetime threshold comprises at least 7 days.

52. The apparatus of claim 45, wherein the controller is further configured to determine the remaining capacity of the power source based on at least one of a voltage of the power source and a current of the power source.

53. The apparatus of claim 45, wherein the duty cycle threshold is bounded between lower and upper bounds of the duty cycle threshold, and wherein the lower and upper and bounds are, respectively, about 9% and about 18%, about 25% and about 60%, and about 35% and about 70%.

54. The apparatus of claim 45, wherein the controller is configured to periodically determine the duty cycle threshold.

55. The apparatus of claim 54, wherein the controller is configured to determine the duty cycle threshold hourly.

56. The apparatus of claim 45, wherein the controller is further configured to:

determine a first capacity of the power source when the negative pressure source is active;

determine a second capacity of the power source when the negative pressure source is inactive; and

determine the capacity of the power source based at least in part on the first and second capacities of the power source.

57. The apparatus of claim 56, wherein the controller is configured to determine the capacity of the power source based on averaging.

58. The apparatus of claim 45, wherein the negative pressure source comprises a voice coil pump.

59. A method for operating a negative pressure apparatus comprising a negative pressure source and a power source, the method comprising:

delivering negative pressure from the negative pressure source to a wound dressing;

monitoring a duty cycle of the negative pressure source, an operational time of the apparatus elapsed from initial activation of the apparatus, and a remaining capacity of the power source;

determining a duty cycle threshold based at least in part on the remaining capacity of the power source and the operational time; and

operating the negative pressure source based at least in part on the determined duty cycle threshold.

60. The method of claim 59, further comprising:

activating the negative pressure source; and

providing an indication in response to determining that the duty cycle has exceeded the duty cycle threshold.

61. The method of claim 60, wherein the indication comprises deactivating the negative pressure source.

62. The method of claim 59, wherein the duty cycle reflects an amount of time the negative pressure source is active over a period of time.

63. The method of claim 59, further comprising determining the duty cycle threshold according to at least one of a quadratic function and a linear function.

64. The method of claim 59, further comprising:

determining the operational time based on a total elapsed time since the initial activation of the apparatus; and

disabling activation of the negative pressure source when the operational time reaches a lifetime threshold.

65. The method of claim 64, wherein the lifetime threshold comprises at least 7 days.

66. The method of claim 59, further comprising determining the remaining capacity of the power source based on at least one of a voltage of the power source and a current of the power source.

67. The method of claim 59, wherein the duty cycle threshold is bounded between lower and upper bounds of the duty cycle threshold, and wherein the lower and upper and bounds are, respectively, about 9% and about 18%, about 25% and about 60%, and about 35% and about 70%.

68. The method of claim 59, further comprising periodically determining the duty cycle threshold.

69. The method of claim 68, further comprising determining the duty cycle threshold hourly.

70. The method of claim 59, further comprising:

determining a first capacity of the power source when the negative pressure source is active;

determining a second capacity of the power source when the negative pressure source is inactive; and

determining the capacity of the power source based at least in part on the first and second capacities of the power source.

71. The method of claim 59, further comprising determining the capacity of the power source using averaging.

72. The method of claim 59, wherein the negative pressure source comprises a voice coil pump.