System and method for providing closed loop infusion formulation delivery

• US 20040220517A1
• Filed: 05/20/2004
• Published: 11/04/2004
• Est. Priority Date: 10/23/2001
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Shah, Rajiv, Miller, Michael E., Starkweather, Timothy J., Lebel, Ronald J.
• Granted Patent: US 8,152,789 B2
• Time in Patent Office: Days
• US Class Current: 604/67
• CPC Class Codes: A61M 2005/14208 with a programmable infusion control system, characterised by the infusion program
• CPC Class Codes: A61M 2230/201 Glucose concentration
• CPC Class Codes: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• CPC Class Codes: G16H 20/17 delivered via infusion or injection
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment

Abstract

A system and method for providing closed loop infusion formulation delivery which accurately calculates a delivery amount based on a sensed biological state by adjusting an algorithm'"'"'s programmable control parameters. The algorithm calculates a delivery amount having proportional, derivative, and basal rate components. The control parameters may be adjusted in real time to compensate for changes in a sensed biological state that may result from daily events. Safety limits on the delivery amount may be included in the algorithm. The algorithm may be executed by a computing element within a process controller for controlling closed loop infusion formulation delivery. The biological state is sensed by a sensing device which provides a signal to the controller. The controller calculates an infusion formulation delivery amount based on the signal and sends commands to an infusion formulation delivery device which delivers an amount of infusion formulation determined by the commands.

Claims

1-35. -35. (Cancelled).

36. A method for delivering a bolus of insulin formulation, the method comprising:

sampling a blood glucose level at predefined timed intervals;

comparing the sampled blood glucose level to a predefined blood glucose level threshold; and

disabling a bolus delivery if the sampled blood glucose level is less than the predefined blood glucose level threshold.

37. The method recited in claim 36, further comprising:

determining if a predefined time interval has been exceeded since a previous bolus delivery; and

disabling the bolus delivery if the predefined time interval has not been exceeded.

38. The method recited in claim 36, further comprising:

determining if the sampled blood glucose level is rising at a predefined rate; and

disabling the bolus delivery if the sampled blood glucose level is rising at a rate less than the predefined rate.

39-48. -48. (Cancelled).

49. A method for disabling a calculation of a delivery rate of an infusion formulation by a computing element in response to a sensed biological state, the method comprising:

determining a time window for disabling a calculation of a delivery rate of an infusion formulation;

sampling a current time;

determining if the current time is within the time window; and

disabling the calculation of the delivery rate of the infusion formulation if the current time is within the time window.

50. The method recited in claim 49, wherein determining a time window further comprises providing programmable start and stop times for the time window.

51. The method recited in claim 50, wherein the programmable start and stop times for the time window are determined from historical physiological data.

52. A method for delivering an insulin formulation, the method comprising:

sampling a blood glucose level at predefined timed intervals;

comparing the sampled blood glucose level to a predefined blood glucose level threshold; and

disabling insulin formulation delivery if the sampled blood glucose level crosses the predefined blood glucose level threshold.

53. The method recited in claim 52, wherein disabling insulin formulation delivery occurs if the sampled blood glucose level is less than the predefined blood glucose level threshold.

54. The method recited in claim 52, wherein the insulin formulation is delivered as a bolus.

55. The method recited in claim 54, further comprising:

determining if a predefined time interval has been exceeded since a previous bolus delivery; and

disabling the bolus delivery if the predefined time interval has not been exceeded.

56. The method recited in claim 54, further comprising:

determining if the sampled blood glucose level is rising at a predefined rate; and

disabling the bolus delivery if the sampled blood glucose level is rising at a rate less than the predefined rate.

57. The method recited in claim 54, further comprising:

determining a time window for disabling a calculation of a delivery rate of the insulin formulation;

sampling a current time;

determining if the current time is within the time window; and

disabling the calculation of the delivery rate of the insulin formulation if the current time is within the time window.

58. The method recited in claim 57, wherein determining a time window further comprises providing programmable start and stop times for the time window.

59. The method recited in claim 58, wherein the programmable start and stop times for the time window are determined from historical physiological data.

60. The method recited in claim 52, further comprising delivering an insulin formulation delivery if the sampled blood glucose level is greater than the predefined blood glucose level threshold.

61. The method recited in claim 52, further comprising:

calculating an amount by which the sampled blood glucose level exceeds the predefined blood glucose level threshold;

determining a rate at which the sampled blood glucose level is changing; and

delivering an amount insulation formulation based on the amount which the sampled blood glucose level exceeds the predefined blood glucose level threshold and the rate at which the sampled blood glucose level is changing.

62. The method recited in claim 61, further comprising introducing an adjustment into the amount of insulation formulation delivered not related to the amount which the sampled blood glucose level exceeds the predefined blood glucose level threshold or the rate at which the sampled blood glucose level is changing.

63. The method recited in claim 62, wherein the adjustment is introduced via programmable control parameters.

64. The method recited in claim 61, wherein determining a rate at which the sampled blood glucose level is changing occurs at predetermined intervals.

65. The method recited in claim 64, wherein the predetermined intervals are programmable.

66. The method recited in claim 61, wherein delivering an insulation formulation comprises delivering a basal rate of insulation formulation.

67. The method recited in claim 61, further comprising calculating an amount by which the sampled blood glucose level is offset over time from the predefined blood glucose level threshold.

68. The method recited in claim 52, further comprising filtering out high frequency components of the sampled blood glucose level.

69. The method recited in claim 68, wherein filtering comprises filtering with a low pass filter.

70. The method recited in claim 68, wherein filtering comprises filtering with a finite impulse response filter.

71. The method recited in claim 57, further comprising enabling the calculation of the delivery rate of the insulin formulation if the current time is not within the time window.

72. The method recited in claim 57, further comprising delivering a minimal insulin formulation if the current time is within the time window.

73. The method recited in claim 57, further comprising delivering no insulin formulation if the current time is within the time window.

74. A system for delivering an insulin formulation comprising:

a data acquisition unit for sampling a blood glucose level at predefined timed intervals;

a comparator for comparing the sampled blood glucose level acquired by the data acquisition unit to a predefined blood glucose level threshold; and

a controller for disabling insulin formulation delivery if the sampled blood glucose level crosses the predefined blood glucose level threshold.

75. The system of claim 74, wherein the controller is configured to disable insulin formulation delivery if the sampled blood glucose level is less than the predefined blood glucose level threshold

76. The system of claim 74, wherein the controller is configured to cause the insulin formulation to be delivered as a bolus.

77. The system of claim 76, wherein the data acquisition unit is further configured to determine if a predefined time interval has been exceeded since a previous bolus delivery;

and

wherein the controller disables the bolus delivery if the predefined time interval has not been exceeded.

78. The system of claim 76, wherein the data acquisition unit is further configured to determine if the sampled blood glucose level is rising at a predefined rate;

and

wherein the controller disables the bolus delivery if the sampled blood glucose level is rising at a rate less than the predefined rate.

79. The system of claim 76, wherein the data acquisition unit is configured to sample a current time;

and

wherein the controller is configured to;

determine a time window for disabling a calculation of a delivery rate of the insulin formulation;

determine if the current time is within the time window; and

disable the calculation of the delivery rate of the insulin formulation if the current time is within the time window.

80. The system of claim 79, wherein the controller is configured to provide programmable start and stop times for the time window.

81. The system of claim 80, wherein the controller determines the programmable start and stop times for the time window from historical physiological data.

82. The system of claim 74, wherein the controller causes an insulin formulation to be delivered if the sampled blood glucose level is greater than the predefined blood glucose level threshold.

83. The system of claim 74, wherein the controller is further configured to:

calculate an amount by which the sampled blood glucose level exceeds the predefined blood glucose level threshold;

determine a rate at which the sampled blood glucose level is changing; and

deliver an amount insulation formulation based on the amount which the sampled blood glucose level exceeds the predefined blood glucose level threshold and the rate at which the sampled blood glucose level is changing.

84. The system of claim 83, wherein the controller is configured to cause an adjustment to be introduced into the amount of insulation formulation delivered not related to the amount which the sampled blood glucose level exceeds the predefined blood glucose level threshold or the rate at which the sampled blood glucose level is changing.

85. The system of claim 84, wherein the controller is configured with programmable control parameters for introduction of the adjustment.

86. The system of claim 83, wherein the controller is configured to determine at predetermined intervals the rate at which the sampled blood glucose level is changing.

87. The system of claim 86, wherein the predetermined intervals are programmable.

88. The system of claim 83, wherein the controller is configured to deliver a basal rate of insulation formulation when delivering an insulation formulation.

89. The system of claim 83, wherein the controller is configured to calculate an amount by which the sampled blood glucose level is offset over time from the predefined blood glucose level threshold.

90. The system of claim 74, further comprising a filter for filtering out high frequency components of the sampled blood glucose level.

91. The system of claim 90, wherein the filter is a low pass filter.

92. The system of claim 90, wherein the filter is a finite impulse response filter.

93. The system of claim 79, wherein the controller is configured to enable the calculation of the delivery rate of the insulin formulation if the current time is not within the time window.

94. The system of claim 79, wherein the controller is configured to cause delivery of a minimal insulin formulation if the current time is within the time window.

95. The system of claim 79, wherein the controller is configured to cause delivery of no insulin formulation if the current time is within the time window.

96. A system for delivering an insulin formulation comprising:

means for sampling a blood glucose level at predefined timed intervals;

means for comparing the sampled blood glucose level to a predefined blood glucose level threshold; and

means for disabling insulin formulation delivery if the sampled blood glucose level crosses the predefined blood glucose level threshold.

97. The system of claim 96, wherein the means for disabling disables insulin formulation delivery if the sampled blood glucose level is less than the predefined blood glucose level threshold.

98. The system of claim 96, wherein the insulin formulation is delivered as a bolus.

99. The system of claim 98, further comprising:

means for determining if a predefined time interval has been exceeded since a previous bolus delivery; and

means for disabling the bolus delivery if the predefined time interval has not been exceeded.

100. The system of claim 98, further comprising:

means for determining if the sampled blood glucose level is rising at a predefined rate; and

means for disabling the bolus delivery if the sampled blood glucose level is rising at a rate less than the predefined rate.

101. The system of claim 98, further comprising:

means for determining a time window for disabling a calculation of a delivery rate of the insulin formulation;

means for sampling a current time;

means for determining if the current time is within the time window; and

means for disabling the calculation of the delivery rate of the insulin formulation if the current time is within the time window.

102. The system of claim 96, further comprising:

means for calculating an amount by which the sampled blood glucose level exceeds the predefined blood glucose level threshold;

means for determining a rate at which the sampled blood glucose level is changing; and

means for delivering an amount insulation formulation based on the amount which the sampled blood glucose level exceeds the predefined blood glucose level threshold and the rate at which the sampled blood glucose level is changing.