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

• US 20140163399A1
• Filed: 12/02/2013
• Published: 06/12/2014
• Est. Priority Date: 02/05/2002
• Status: Active Grant

• Current Assignee: United States GTM Medical Devices
• Original Assignee: Tensys Medical Inc. (Recorders & Medicare Systems Pvt Ltd.)
• Inventors: Gallant, Stuart L., Voss, Gregory I., Markle, William H.
• Granted Patent: US 9,814,398 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 for determining a substantially optimum location for applanating a blood vessel, comprising:

placing a transducer proximate to one side of a blood vessel at a starting position laterally offset from said substantially optimum location for applanating said blood vessel;

automatically moving said transducer laterally over said blood vessel from said starting position to an ending position past said substantially optimum location for applanating said blood vessel on a second side of said blood vessel while simultaneously measuring a pulse pressure of said blood vessel via said transducer; and

automatically moving said transducer laterally over said blood vessel from said ending position to place said transducer over said substantially optimum location.

76. The method of claim 75, further comprising determining said substantially optimum location of said blood vessel based at least in part on said measured pulse pressure of said blood vessel reaching a substantial maximum during said act of automatically moving said transducer laterally over said blood vessel form said starting position to said ending position.

77. The method of claim 75, wherein said acts of automatically moving said transducer laterally over said blood vessel each comprise moving said transducer substantially continuously.

78. The method of claim 75, wherein said acts of moving said transducer laterally over said blood vessel each comprise moving said transducer at a substantially constant rate.

79. The method of claim 75, wherein said act of simultaneously measuring said pulse pressure of said blood vessel comprises measurement thereof substantially continuously from said starting position to said ending position.

80. The method of claim 75, further comprising maintaining a substantially constant level of compression by said transducer to said blood vessel during said act of automatically moving said transducer laterally over said blood vessel from said starting position to said ending position.

81. The method of claim 80, wherein said level of compression comprises a level which is sufficient to compress said blood vessel at least partially.

82. A method, comprising:

positioning a transducer laterally offset from a central portion of a blood vessel;

automatically sweeping said transducer laterally over said blood vessel past said central portion while simultaneously measuring a pulse pressure of said blood vessel via said transducer; and

automatically repositioning said transducer over said central portion of said blood vessel based at least in part on said pulse pressure measured during said act of sweeping.

83. The method of claim 82, wherein said act of automatically sweeping said transducer laterally over said blood vessel further comprises moving said transducer substantially continuously.

84. The method of claim 82, wherein said act of automatically sweeping said transducer laterally over said blood vessel further comprises moving said transducer at a substantially constant rate.

85. The method of claim 82, wherein said act of automatically sweeping said transducer laterally over said blood vessel further comprises moving said transducer via a stepper motor coupled to said transducer.

86. The method of claim 82, wherein said act of automatically repositioning said transducer further comprises automatically repositioning said transducer over said central portion of said blood vessel based at least in part on said pulse pressure measured during said act of sweeping reaching an approximate maximum.

87. The method of claim 82, wherein said pulse pressure measured during said act of sweeping is based on systolic and diastolic components obtained from a pressure waveform indicated by said transducer.

88. The method of claim 82, wherein said act of measuring said pulse pressure of said blood vessel via said transducer further comprises measuring said pulse pressure of said blood vessel substantially continuously during said act of automatically sweeping said transducer laterally over said central portion of said blood vessel.

89. The method of claim 82, further comprising maintaining a substantially constant level of compression by said transducer to said blood vessel during said act of automatically sweeping said transducer laterally over said blood vessel past said central portion.

90. The method of claim 88, wherein said level of compression comprises a level which is sufficient to compress said blood vessel at least partially.

91. An apparatus for measuring blood pressure, comprising:

an applanator structure;

a transducer coupled to said applanator structure, said transducer configured to indicate pressure of a blood vessel; and

an actuator assembly coupled to said applanator structure and said transducer;

wherein said actuator assembly is further configured to laterally sweep said applanator structure and said transducer over said blood vessel and to vary an amount of applanation applied by said applanator structure and said transducer to said blood vessel.

92. The apparatus of claim 91, wherein said actuator assembly comprises a motor.

93. The apparatus of claim 92, wherein said motor comprises a stepper motor.

94. The apparatus of claim 91, wherein said actuator assembly further comprises a position encoder configured to facilitate control of positioning of said applanator structure and said transducer.

95. The apparatus of claim 91, further comprising a processor configured to facilitate determination of a substantially optimum location of said transducer based on said indication of said pressure of said blood vessel reaching a substantial maximum.

96. The apparatus of claim 91, wherein said lateral sweep of said applanator structure and said transducer over said blood vessel comprises a substantially continuous sweep thereof.

97. The apparatus of claim 91, wherein said lateral sweep of said applanator structure and said transducer over said blood vessel comprises a sweep at a substantially constant rate.

98. The apparatus of claim 91, wherein said transducer is further configured to measure pressure of said blood vessel substantially continuously while said actuator assembly performs said lateral sweep of said applanator structure and said transducer over said blood vessel.

99. The apparatus of claim 91, wherein said actuator assembly is further configured to maintain a compression applied by said transducer to said blood vessel substantially constant during said lateral sweep of said applanator structure and said transducer over said blood vessel.