Apparatus and method for measuring transit time of oxygen in blood
First Claim
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1. A method for measuring a transit time of oxygen in blood, comprising:
- attaching a single sensor to a prescribed position on a subject, the sensor being adapted to detect a light absorption of arterial blood at the prescribed position;
calculating an oxygen saturation of the arterial blood at the prescribed position, based on the detected light absorption;
varying an amount of oxygen inspired into the subject at a reference time point;
detecting a change in the calculated oxygen saturation at the prescribed position;
measuring a time period from the reference time point to a time point at which the oxygen saturation changes; and
outputting the measured time period as the transit time.
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Abstract
In order to measure a transit time of oxygen in blood, at least one sensor is attached to at least one prescribed position on a subject. The sensor is adapted to detect a light absorption of arterial blood at the prescribed position. An oxygen saturation of the arterial blood at the prescribed position is calculated based on the detected light absorption. An amount of oxygen inspired into the subject is varied at a reference time point. A change in the calculated oxygen saturation at the prescribed position is detected. A time period from the reference time point to a time point at which the oxygen saturation changes is measured.
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Citations
15 Claims
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1. A method for measuring a transit time of oxygen in blood, comprising:
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attaching a single sensor to a prescribed position on a subject, the sensor being adapted to detect a light absorption of arterial blood at the prescribed position; calculating an oxygen saturation of the arterial blood at the prescribed position, based on the detected light absorption; varying an amount of oxygen inspired into the subject at a reference time point; detecting a change in the calculated oxygen saturation at the prescribed position; measuring a time period from the reference time point to a time point at which the oxygen saturation changes; and outputting the measured time period as the transit time. - View Dependent Claims (2, 3, 4)
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5. An apparatus for measuring a transit time of oxygen in blood, comprising:
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a single sensor, adapted to be attached to a prescribed position on a subject, the sensor being operable to detect a light absorption of arterial blood at the prescribed position; a first calculator, operable to calculate an oxygen saturation of the arterial blood at the prescribed position, based on the detected light absorption; a first detector, operable to detect a first time point at which an amount of oxygen inspired into the subject is varied; and a second detector, operable to detect a second time point at which the calculated oxygen saturation changes to determine a time period from the first time point to the second time point. - View Dependent Claims (6, 7, 8)
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9. A method for measuring a transit time difference of oxygen in blood between prescribed positions of a subject, comprising:
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attaching a plurality of sensors to the prescribed positions on the subject, each of the sensors being adapted to detect a light absorption of arterial blood at one of the prescribed positions; calculating an oxygen saturation of the arterial blood at each of the prescribed positions, based on the detected light absorption detected by each of the sensors; varying an amount of oxygen inspired into the subject; detecting a change in the calculated oxygen saturation at each of the prescribed positions; obtaining a cross-correlation coefficient between attenuation rates or oxygen saturations measured by the sensors; determining the transit time difference, based on a time point at which the cross-correlation coefficient becomes maximum; and outputting the determined transit time difference. - View Dependent Claims (10, 11)
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12. An apparatus for measuring a transit time difference of oxygen in blood between prescribed positions of a subject, comprising:
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a plurality of sensors, adapted to be attached to the prescribed positions on the subject, each of the sensors being operable to detect a light absorption of arterial blood at one of the prescribed positions; a first calculator, operable to calculate an oxygen saturation of the arterial blood at each of the prescribed positions, based on the detected light absorption; a first detector, operable to detect a change in the calculated oxygen saturation at each of the prescribed positions when an amount of oxygen inspired into the subject is varied; a second calculator, operable to obtain a cross-correlation coefficient between attenuation rates or oxygen saturations measured by the sensors, and a third calculator, operable to determine the transit time difference based on a time point at which the cross-correlation coefficient becomes maximum. - View Dependent Claims (13, 14, 15)
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Specification