METHODS AND APPARATUS FOR CONTROL OF NON-INVASIVE PARAMETER MEASUREMENTS

• US 20110237961A1
• Filed: 06/06/2011
• Published: 09/29/2011
• Est. Priority Date: 08/01/2002
• Status: Active Grant

• Current Assignee: United States GTM Medical Devices
• Original Assignee: Gregory I. Voss, Gregory J. Martin, Manouchehr Goharlaee
• Inventors: Voss, Gregory I., Martin, Gregory J., Goharlaee, Manouchehr
• Granted Patent: US 8,945,016 B2
• Time in Patent Office: Days
• US Class Current: 600/485
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• 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 5/684 Indicating the position of the sensor on the body
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00

Abstract

Improved methods and apparatus for non-invasively assessing one or more parameters associated with fluidic systems such as the circulatory system of a living organism. In a first aspect, an improved method of continuously measuring pressure from a compressible vessel is disclosed, wherein a substantially optimal level of compression for the vessel is achieved and maintained using perturbations (e.g., modulation) of the compression level of the vessel. In one exemplary embodiment, the modulation is conducted according to a pseudo-random binary sequence (PBRS). In a second aspect, an improved apparatus for determining the blood pressure of a living subject is disclosed, the apparatus generally comprising a pressure sensor and associated processor with a computer program defining a plurality of operating states related to the sensed pressure data. Methods for pressure waveform correction and reacquisition, as well as treatment using the present invention, are also disclosed.

Claims

1-68. -68. (canceled)

69. A method of operating a hemodynamic parameter measurement apparatus adapted for use on a living subject and having one or more sensors in contact with tissue overlying a blood vessel, the method comprising:

operating said apparatus in a non-transient mode, wherein data relating to one or more hemodynamic parameters is obtained using said one or more sensors;

detecting at least one transient event using said obtained data; and

operating said apparatus in a transient recovery mode subsequent to said detection of said event so as to compensate for said transient event.

70. The method of claim 69, wherein the transient event changes the coupling of the sensor to the tissue, thereby potentially affecting the accuracy of the obtained data.

71. The method of claim 70, wherein said detecting comprises detecting a reduction in the magnitude of one or more pressure values.

72. The method of claim 70, wherein said detecting comprises detecting the absence of one or more cardiac beats in said obtained data.

73. The method of claim 70, wherein the hemodynamic parameter comprises blood pressure, and at least one of said one or more sensors comprises a tonometric or non-invasive pressure sensor.

74. The method of claim 70, wherein the transient recovery mode comprises temporarily suspending use of obtained data.

75. The method of claim 74, wherein the transient recovery mode further comprises adjusting the position of at least one of the one or more sensors obtaining the data.

76. The method of claim 75, wherein the blood vessel comprises the radial artery, and the adjusting the position of at least one of the one or more sensors obtaining the data comprises adjusting at least one of the lateral and/or proximal position of the at least one sensor relative to said artery.

77. The method of claim 75, wherein the blood vessel comprises the radial artery, and the adjusting the position of at least one of the one or more sensors obtaining the data comprises adjusting applanation or compression level of the at least one sensor relative to said tissue.

78. The method of claim 69, wherein the detecting comprises detecting a reduction in the magnitude of a parameter represented by said data.

79. The method of claim 78, wherein said detecting a reduction comprises detecting a reduction in the magnitude of a pulse pressure.

80. The method of claim 69, wherein said detecting comprises detecting the absence of one or more cardiac beats in said data.

81. An apparatus for use in transient event compensation during hemodynamic parameter measurement from a living subject, comprising:

first apparatus adapted to establish an initial substantially optimal state of coupling to said living subject;

a sensor adapted to obtain data relating to said hemodynamic parameter from said subject; and

a computing apparatus having a computer program configured to run thereon, which when executed;

cause said data to be received from said sensor;

detect the occurrence of a transient event by analyzing changes in said data, said transient event altering the mechanical coupling between said subject and sensor;

cease use of said data from said sensor;

identify a second substantially optimal state of coupling of said sensor to said subject; and

resume using said data from said sensor after said second state has been achieved.

82. The apparatus of claim 81, wherein said computing apparatus initiates a sweep through a plurality of different states to identify said second substantially optimal state of coupling.

83. The apparatus of claim 82, wherein said computer program causes said sweep to begin only after said transient event substantially subsides.

84. The apparatus of claim 81, wherein said computing apparatus controls said first apparatus to establish said second substantially optimal state.

85. The apparatus of claim 81, wherein said initial and second substantially optimal states comprise states of compression of tissue overlying a blood vessel.

86. The apparatus of claim 81, wherein said detection of the occurrence of a transient event comprises comparison of at least one of (i) a measured pressure, (ii) a measured velocity and/or (iii) a measured acceleration, with one or more predetermined values.

87. A non-invasive physiologic measurement apparatus, comprising:

a sensor adapted to measure a physiologic parameter originating from a living subject;

a sensor control apparatus operatively coupled to said sensor; and

a controller in signal communication with said sensor and said sensor control apparatus and configured to;

operate in a first mode to collect data using said sensor;

detect at least one instance of said collected data being unreliable;

upon detection of said unreliable data, operate in a second mode to cease at least one of collection and/or use of said data for at least a period during which said data is unreliable; and

upon completion of said period during which said data is unreliable, operate in a third mode to resume collection and/or use of said data from said sensor.

88. The apparatus of claim 87, wherein said second mode is entered subsequent to said detection of said unreliable data only if a parameter related to said determination of unreliability of said data is of sufficient magnitude that recovery from said event in said first mode would exceed a first criterion.

89. The apparatus of claim 88, wherein said first criterion comprises a time period or duration.

90. The apparatus of claim 87, wherein said period during which said data is unreliable is terminated by selectively adjusting said sensor control apparatus via a control signal so as to re-establish a substantially optimal level of coupling between said sensor and tissue of said living subject.

91. A non-invasive hemodynamic measurement system, comprising:

a sensor adapted to measure at least one hemodynamic parameter;

control apparatus operatively coupled to said sensor;

a controller in signal communication with said sensor and said control apparatus, said controller capable of

generating a waveform related to hemodynamic data obtained from said sensor;

identifying at least one artifact within said waveform, said at least one artifact indicating unreliability of said hemodynamic data,

subsequent to identifying said unreliability, ceasing utilizing said hemodynamic data collected from said sensor to generate said waveform; and

at a termination of said unreliability, restarting utilization of said hemodynamic data collected from said sensor to generate said waveform.

92. The system of claim 91, wherein said identifying at least one artifact within a waveform related to said hemodynamic data comprises detecting changes in a first hemodynamic parameter value with respect to a predetermined value therefore.

93. A method of operating a hemodynamic assessment apparatus adapted for use on a living subject and having a sensor, the method comprising:

collecting hemodynamic parameter data using said sensor coupled to tissue of said subject;

utilizing said data to determine a pressure value of interest of said living subject;

detecting the occurrence of a transient event by analyzing changes in said data, said transient event adversely affecting said coupling;

ceasing collection of said data from said sensor; and

resuming receiving said hemodynamic parameter measurement data from said sensor upon termination of said transient event and re-establishing adequate coupling of said sensor to said tissue.

94. The method of claim 93, wherein said transient event comprises a motion initiated by a subject from which said hemodynamic data is being obtained.

95. The method of claim 93, wherein said act of detecting the occurrence of said transient event comprises identifying at least one artifact within a waveform related to said hemodynamic data.

96. The method of claim 95, wherein said act of identifying at least one artifact within a waveform related to said hemodynamic data comprises detecting changes in a first averaged pulse pressure value with respect to a second averaged pulse pressure value.

97. The method of claim 93, wherein said pressure value of interest comprises a pulse pressure value.