METHOD AND APPARATUS FOR NON-INVASIVELY MEASURING HEMODYNAMIC PARAMETERS USING PARAMETRICS

• US 20110166458A1
• Filed: 01/10/2011
• Published: 07/07/2011
• Est. Priority Date: 02/05/2002
• Status: Active Grant

• Current Assignee: United States GTM Medical Devices
• Original Assignee: Gregory I. Voss, Stuart L. Gallant, William H. Markle
• Inventors: Markle, William H., Voss, Gregory I., Gallant, Stuart L.
• Granted Patent: US 8,597,195 B2
• Time in Patent Office: Days
• US Class Current: 600/485
• CPC Class Codes: A61B 2562/02 Details of sensors specially adapted for in-vivo measurements
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure

Abstract

An improved method and apparatus for non-invasively assessing one or more hemodynamic parameters associated with the circulatory system of a living organism. In one aspect, the invention comprises a method of measuring a hemodynamic parameter (e.g., arterial blood pressure) by applanating or compressing portions of tissue proximate to the blood vessel of concern until a desired condition is achieved, and then measuring the hemodynamic parameter. Such applanation effectively mitigates transfer and other losses created by the tissue proximate to the blood vessel, thereby facilitating accurate and robust tonometric measurement. An algorithm adapted to maintain optimal levels of applanation is also described. Methods and apparatus for scaling such hemodynamic parameter measurements based on subject physiology, and providing treatment to the subject based on the measured parameters, are also disclosed.

Claims

1-74. -74. (canceled)

75. A method of measuring the pulse pressure of a living subject, comprising:

obtaining via pressure sensor a plurality of pressure values associated with a blood vessel of said living subject;

deriving a scaling factor based on at least one physiological parameter;

using at least one algorithm run on a processor associated with said pressure sensor to scale said plurality of pressure values using said scaling factor; and

utilizing at least said scaled pressure values to generate a pulse pressure value of said living subject.

76. The method of claim 75, wherein said at least one physiological parameter scaling factor is based on at least one of body mass index (BMI) and/or wrist circumference (WC).

77. The method of claim 76, wherein said act of obtaining said plurality of pressure values comprises applanating said blood vessel of said living subject via said pressure sensor.

78. The method of claim 77, wherein said living subject comprises a human being, and said act of applanating is performed substantially contemporaneously with said act of measuring said plurality of pressure values.

79. Apparatus adapted to measure the pressure of a blood vessel of a living subject, comprising:

a digital processor;

a pressure sensor adapted to generate a signal relating to pressure applied thereto; and

at least one computer program configured to run on the digital processor and further configured to scale said signal using a scaling factor based at least in part on a derived parameter particularly associated with the physiology of said subject.

80. The apparatus of claim 79, further comprising a bias element disposed proximate to said pressure sensor and adapted to mitigate the effects of tissue interposed between said sensor and said blood vessel, said bias element substantially surrounding at least a portion of said pressure sensor.

81. The apparatus of claim 79, further comprising an applanation apparatus adapted to controllably press at least a portion of said pressure sensor and said bias element against said tissue.

82. The apparatus of claim 79, wherein said signals relating to said pressure comprise a measurement of systolic and diastolic pressure of said subject.

83. The apparatus of claim 79, wherein said derived parameter particularly associated with said subject comprises body mass index.

84. The apparatus of claim 83, further comprising a user interface operative to receive data entered by a user, said data relating to at least said body mass index.

85. The apparatus of claim 79, wherein said living subject comprises a human being, and said bias element uses at least said pressure sensor to at least partly applanate the radial artery of said human being, said at least partial applanation being performed while said signal is being generated.

86. A method of measuring the pulse pressure of a living subject, comprising:

utilizing a pressure sensor to obtain a plurality of pressure values associated with a systolic and diastolic pressure of a blood vessel of said living subject;

utilizing said plurality of pressure values to determine a pulse pressure of said living subject;

deriving a scaling factor based at least in part on at least one physiologic parameter;

scaling said determined pulse pressure using said scaling factor using at least one algorithm run on a processor associated with said pressure sensor; and

presenting said scaled pulse pressure to a user.

87. The method of claim 86, wherein said at least one physiological parameter comprises a body mass index (BIM of said subject.

88. The method of claim 87, wherein said act of determining said derivation of said scaling factor comprises utilizing one or more inputs received from a user via a user interface.

89. A method of measuring the pulse pressure of a living subject, comprising:

utilizing a pressure sensor to measure a plurality of pressure values of a blood vessel of said living subject;

determining a physiological parameter of said living subject;

deriving a scaling factor based at least in part on said physiological parameter;

scaling said plurality of pressure values using said scaling factor; and

utilizing said scaled pressure values to generate at least one pulsatile pressure value.

90. The method of claim 89, wherein said first physiological parameter comprises body mass index (BMI).

91. The method of claim 89, wherein said first physiological parameter comprises wrist circumference (WC).

92. The method of claim 89, wherein said act of utilizing a pressure sensor measure said plurality of pressure values of a blood vessel comprises obtaining a tonometric measurement of a systolic and diastolic pressure of said living subject.

93. Apparatus for measuring the pulse pressure of a living subject, comprising:

a first means for generating a signal relating to pressure in a blood vessel of said subject;

a second means for scaling said signal using a scaling factor, said scaling factor comprising a value derived from at least one physiological parameter of said subject; and

a third means for outputting as a value for said pulse pressure said scaled signal.

94. The apparatus of claim 93, wherein said signal is affected at least in part by tissue interposed between said first means and a blood vessel of said subject, and said apparatus further comprises a fourth means for mitigating the effects of said tissue on said signal, said first and fourth means being disposed proximate to one another.

95. The apparatus of claim 94, further comprising a means for controllably pressing at least a portion of said first and fourth means against said tissue.

96. The apparatus of claim 93, wherein further comprising a bias element substantially enveloping at least a portion of said first means.

97. The apparatus of claim 93, wherein said at least one physiological parameter comprises body mass index (BMI), and said apparatus further comprises a means for receiving data relating to said subject'"'"'s weight and said subject'"'"'s height from a user, said BMI being calculated from said weight and height data.

98. The apparatus of claim 93, wherein said physiological parameter comprises wrist circumference.

99. The apparatus of claim 96, wherein said living subject comprises a human being, and said apparatus uses at least said bias element to at least partly applanate the radial artery of said human being, said at least partial applanation being performed while said signal is being generated.