Method and system for non-invasive determination of blood-related parameters
First Claim
1. A non-invasive method for use in determining at least one desired characteristic of blood of a patient, the method comprising:
- (a) creating a condition of artificial blood kinetics at a measurement location in a patient'"'"'s blood perfused fleshy medium and maintaining this condition for a certain time period;
(b) applying an external electromagnetic field to the measurement location;
(c) detecting a time response of the medium from at least a portion of the measurement location to said external electromagnetic field, the response including at least one of an acoustic response to illuminating incident light having a wavelength in a range where the scattering properties of blood are sensitive to light radiation or an impedance of the portion of the medium;
(d) generating measured data indicative of time evolutions of the response of the medium over at least a part of said certain time period;
(e) analyzing said measured data for determining at least one characteristic parameter derived from said time response of the medium, the characteristic parameter including at least one of an actual value of the time response at a certain moment, during said certain time period, chosen when the response attains its near asymptotic magnitude; and
a parametric slope defined as a ratio between a first function depending on a time response of the medium corresponding to a first frequency of the external electromagnetic field or a second function depending on the time response of the medium corresponding to a second frequency;
(f) providing predetermined reference data sensitive to patient individuality and indicative of the desired blood characteristic obtained by other independent method as a function of said at least one characteristic parameter; and
(g) utilizing the determined characteristic parameter derived from said time response of the medium and said predetermined reference data for obtaining a value of the desired blood characteristic.
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Accused Products
Abstract
A method and system for measuring time variations of a response of a blood perfused fleshy medium to an external electromagnetic field is provided. The response of the medium to the external electromagnetic field can be a photo-acoustic signal, obtained in response to the exciting light, and/or impedance of the medium, in response to the applied ac electromagnetic field. Measurements of the time variations of the response of the medium are carried out when the condition of artificial kinetics is created and maintained over a certain time period by applying primary over-systolic pressure to a certain location at the medium with normal blood flow, so as to achieve a state of temporary blood flow cessation at the medium downstream of the certain location. When required, the control of the condition of the artificial kinetics can be further achieved by applying a perturbation of secondary pressure to the fleshy medium.
32 Citations
35 Claims
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1. A non-invasive method for use in determining at least one desired characteristic of blood of a patient, the method comprising:
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(a) creating a condition of artificial blood kinetics at a measurement location in a patient'"'"'s blood perfused fleshy medium and maintaining this condition for a certain time period; (b) applying an external electromagnetic field to the measurement location; (c) detecting a time response of the medium from at least a portion of the measurement location to said external electromagnetic field, the response including at least one of an acoustic response to illuminating incident light having a wavelength in a range where the scattering properties of blood are sensitive to light radiation or an impedance of the portion of the medium; (d) generating measured data indicative of time evolutions of the response of the medium over at least a part of said certain time period; (e) analyzing said measured data for determining at least one characteristic parameter derived from said time response of the medium, the characteristic parameter including at least one of an actual value of the time response at a certain moment, during said certain time period, chosen when the response attains its near asymptotic magnitude; and
a parametric slope defined as a ratio between a first function depending on a time response of the medium corresponding to a first frequency of the external electromagnetic field or a second function depending on the time response of the medium corresponding to a second frequency;(f) providing predetermined reference data sensitive to patient individuality and indicative of the desired blood characteristic obtained by other independent method as a function of said at least one characteristic parameter; and (g) utilizing the determined characteristic parameter derived from said time response of the medium and said predetermined reference data for obtaining a value of the desired blood characteristic. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A system for non-invasive determination of at least one desired characteristic of blood of a patient, the system comprising:
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(i) a pressurizing assembly arranged for creating a condition of artificial blood kinetics at a measurement location in a patient'"'"'s blood perfused fleshy medium and at least maintaining this condition for a certain time period, the pressurizing assembly comprising a primary occlusion cuff for applying a primary over-systolic pressure to the fleshy medium at a primary pressure location, and a secondary occlusion cuff for applying a secondary pressure to the flesh medium at a secondary pressure location, thereby altering the condition of the artificial blood kinetics at said secondary pressure location over a predetermined time interval within said certain time period so as to modulate properties of the blood affecting said time response; (ii) a measuring probe including a source of an external electromagnetic field configured for applying said external electromagnetic field to said measurement location, and a detecting module configured for detecting a time response of the medium from at least a portion of the measurement location to said external electromagnetic field; and (iii) a control unit electrically coupled to said pressurizing assembly, said control unit including; a memory for storing reference data sensitive to patient individuality and indicative of the desired blood characteristic as a function of a characteristic parameter derived from said time response; and a data acquisition and processing utility coupled to the detecting module for receiving and analyzing measured data therefrom and configured to utilize the reference data and determine said at least one desired blood characteristic. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A system for non-invasive determination of at least one desired characteristic of blood of a patient, the system comprising:
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(i) a pressurizing assembly arranged for creating a condition of artificial blood kinetics at a measurement location in a patient'"'"'s blood perfused fleshy medium and at least maintaining this condition for a certain time period; (ii) a measuring probe comprising a source of an external electromagnetic field configured for applying said external electromagnetic field to said measurement location, said source of the external electromagnetic field being configured for generating a light beam in the wavelength range where the scattering or absorbing properties of the patients blood are sensitive to provide an acoustic response, and a detecting module comprising an acoustic detector configured for detecting a time response of the medium from at least a portion of the measurement location to said external electromagnetic field; and (iii) a control unit electrically coupled to said pressurizing assembly, said control unit comprising a memory for storing reference data sensitive to patient individuality and indicative of the desired blood characteristic as a function of a characteristic parameter derived from said time response; and a data acquisition and processing utility coupled to the detecting module for receiving and analyzing measured data therefrom and configured to utilize the reference data and determine said at least one desired blood characteristic. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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Specification