Methods and apparatus for control of non-invasive parameter measurements
First Claim
1. A hemodynamic measurement apparatus configured to obtain hemodynamic data and identify a transient event which affects a coupling between a sensor and a tissue surface that at least partially overlies a blood vessel of interest, said apparatus comprising:
- a pressure sensor configured to collect said hemodynamic data, said pressure sensor configured to generate a waveform related to said hemodynamic data;
an applanation and/or positioning mechanism configured to establish an optimal coupling between said sensor and said tissue surface that at least partially overlies said blood vessel of interest;
a controller in signal communication with said sensor and said applanation and/or positioning mechanism, said controller configured to detect said transient event;
a modulator process configured to, upon detection of said transient event, introduce changes in said waveform via said applanation and/or positioning mechanism, said changes being associated with a modulation of a compression applied to said tissue surface via a pseudo-random binary sequence; and
a signal restoration process configured to anticipate said changes in said waveform introduced by said modulator process and to correct at least portions of said waveform by use of a pressure correction offset to restore said waveform to a shape that is equivalent to an un-modulated waveform;
wherein upon detection of said transient event, said controller is further configured to;
(i) temporally cease collection of and/or use of said hemodynamic data during a period which said hemodynamic data is unreliable, and (ii) resume at least one of collection and/or use of said hemodynamic data upon termination of said transient event.
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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.
55 Citations
40 Claims
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1. A hemodynamic measurement apparatus configured to obtain hemodynamic data and identify a transient event which affects a coupling between a sensor and a tissue surface that at least partially overlies a blood vessel of interest, said apparatus comprising:
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a pressure sensor configured to collect said hemodynamic data, said pressure sensor configured to generate a waveform related to said hemodynamic data; an applanation and/or positioning mechanism configured to establish an optimal coupling between said sensor and said tissue surface that at least partially overlies said blood vessel of interest; a controller in signal communication with said sensor and said applanation and/or positioning mechanism, said controller configured to detect said transient event; a modulator process configured to, upon detection of said transient event, introduce changes in said waveform via said applanation and/or positioning mechanism, said changes being associated with a modulation of a compression applied to said tissue surface via a pseudo-random binary sequence; and a signal restoration process configured to anticipate said changes in said waveform introduced by said modulator process and to correct at least portions of said waveform by use of a pressure correction offset to restore said waveform to a shape that is equivalent to an un-modulated waveform; wherein upon detection of said transient event, said controller is further configured to;
(i) temporally cease collection of and/or use of said hemodynamic data during a period which said hemodynamic data is unreliable, and (ii) resume at least one of collection and/or use of said hemodynamic data upon termination of said transient event. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A non-transitory computer readable apparatus comprising a plurality of instructions which are configured to, when executed by a processor:
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cause optimal coupling to be established between an applanation and/or positioning mechanism having at least a sensor associated therewith and a tissue surface that overlies a blood vessel of interest; cause said sensor to collect hemodynamic data, said hemodynamic data comprising one or more parameters; evaluate said collected hemodynamic data to identify an occurrence of a transient event which affects said optimal coupling via analysis of changes in said one or more parameters; and when said changes to said one or more parameters meet one or more criterion; cause said sensor to cease collection of said data; cause said applanation and/or positioning mechanism to initiate a pressure sweep to re-establish said optimal coupling; and cause said sensor to resume collection of said hemodynamic data upon termination of said transient event and said re-establishment of said optimal coupling. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A non-transitory computer readable apparatus comprising a plurality of instructions which are configured to, when executed by a processor:
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establish an optimal coupling between a sensor and a tissue surface that at least partially overlies a blood vessel of interest; generate a waveform related to a plurality of hemodynamic data collected by said sensor; detect a transient event which affects said coupling between said sensor and said tissue surface that at least partially overlies said blood vessel of interest; upon detection of said transient event; introduce changes in said waveform via an applanation and/or positioning mechanism, said changes being associated with a modulation of a compression applied to said tissue surface via a pseudo-random binary sequence; anticipate said changes in said waveform and correct at least portions of said waveform by use of a pressure correction offset to restore said waveform to a shape that is equivalent to an un-modulated waveform; temporally cease collection of and/or use of said hemodynamic data during a period which said hemodynamic data is unreliable; and resume at least one of collection and/or use of said hemodynamic data upon termination of said transient event. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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29. A method of operating a hemodynamic assessment apparatus comprising an applanation and/or positioning mechanism, a sensor, and computerized logic configured to identify a transient event affecting a coupling between said sensor and a tissue surface overlying a blood vessel of interest, said method comprising:
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establishing an optimal coupling via said applanation and/or positioning mechanism; collecting hemodynamic data using said sensor, said hemodynamic data comprising one or more parameters; detecting, using said computerized logic, an occurrence of said transient event affecting said optimal coupling by determining that changes in said one or more parameters of said collected hemodynamic data meet one or more criterion; and during said transient event; ceasing collection of said data by said sensor; and initiating a pressure sweep to re-establish said optimal coupling via said applanation and/or positioning mechanism; and upon termination of said transient event, said sensor resuming collection of said hemodynamic data and said re-establishing said optimal coupling. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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Specification