Method and apparatus for non-invasively measuring hemodynamic parameters using parametrics
First Claim
1. A method for determining an 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 at a first rate, said ending position being past said substantially optimum location for applanating said blood vessel on a second side of said blood vessel, said automatic moving occurring while simultaneously measuring pulse pressure of said blood vessel via said transducer in order to collect a first pulse pressure data set;
automatically backtracking said transducer laterally over said blood vessel from said ending position toward said starting position at a second rate, said automatic backtracking occurring while simultaneously measuring pulse pressure of said blood vessel via said transducer in order to collect a second pulse pressure data set;
based at least in part on a correlation between said first and second pulse pressure data sets, determining said optimum location; and
based at least in part on said determination of said optimum location, automatically positioning said transducer over said blood vessel to place said transducer over said substantially optimum location.
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Accused Products
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.
120 Citations
20 Claims
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1. A method for determining an optimum location for applanating a blood vessel, comprising:
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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 at a first rate, said ending position being past said substantially optimum location for applanating said blood vessel on a second side of said blood vessel, said automatic moving occurring while simultaneously measuring pulse pressure of said blood vessel via said transducer in order to collect a first pulse pressure data set; automatically backtracking said transducer laterally over said blood vessel from said ending position toward said starting position at a second rate, said automatic backtracking occurring while simultaneously measuring pulse pressure of said blood vessel via said transducer in order to collect a second pulse pressure data set; based at least in part on a correlation between said first and second pulse pressure data sets, determining said optimum location; and based at least in part on said determination of said optimum location, automatically positioning said transducer over said blood vessel to place said transducer over said substantially optimum location. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method, comprising:
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positioning a transducer laterally offset from a central portion of a blood vessel; in a first sweep procedure, automatically sweeping said transducer laterally over said blood vessel past said central portion while simultaneously measuring pulse pressure of said blood vessel via said transducer; in a second sweep procedure, automatically backtracking said transducer laterally over said blood vessel past said central portion substantially along a pathway of said first sweep procedure while simultaneously measuring pulse pressure of said blood vessel via said transducer; determining a correlation between (i) a first location based at least on an optimal pulse pressure measured during said first sweep procedure and (ii) a second location based at least on an optimal pulse pressure measured during said second sweep procedure; and based at least in part on said correlation being within a prescribed error band, automatically repositioning said transducer over an optimal location within said central portion of said blood vessel, said optimal location based at least in part on one or more said first or second locations. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. An apparatus configured to determine an optimum location for applanating a blood vessel, the apparatus comprising:
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processor apparatus; transducer apparatus in data communication with said processor apparatus; storage apparatus in data communication with said processor apparatus, said storage apparatus having at least one computer program stored thereon, said at least one computer program comprising a plurality of instructions which are configured to, when executed, cause said apparatus to; in a first sweep procedure, automatically move said transducer apparatus laterally over said blood vessel from a starting position to an ending position, said ending position being past said relative optimum location for applanating said blood vessel on a second side of said blood vessel; simultaneously with said automatic movement of said transducer apparatus during said first sweep procedure, measure a pulse pressure of said blood vessel via said transducer apparatus to collect a first pulse pressure data set; in a second sweep procedure, automatically backtrack said transducer apparatus laterally over said blood vessel from said ending position toward said starting position; simultaneously with said automatic backtrack of said transducer apparatus during said second sweep procedure, measure a pulse pressure of said blood vessel via said transducer to collect a second pulse pressure data set; analyze (i) said first pulse pressure data set to identify a first location based at least on an optimal pulse pressure measured during said first sweep procedure, and (ii) said second pulse pressure data set to identify a second location based at least on an optimum pulse pressure measured during said second sweep procedure; determine a correlation between said first location and said second location; based at least in part on said correlation being within a prescribed error band, automatically reposition said transducer apparatus over a relative optimum location within a central portion of said blood vessel, said relative optimum location based at least in part on one or more said first or second locations; and based at least in part on said correlation being outside of said prescribed error band, automatically perform at least a third sweep procedure to collect at least a third pulse pressure data set. - View Dependent Claims (20)
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Specification