Device for measuring physiological state

• US 6,331,159 B1
• Filed: 08/11/2000
• Issued: 12/18/2001
• Est. Priority Date: 11/01/1995
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Amano, Kazuhiko, Ishiyama, Hitoshi, Uebaba, Kazuo
• Primary Examiner(s): Lacyk, John P.
• Assistant Examiner(s): Astorino, Michael
• Application Number:
  US09/636,775
• Time in Patent Office: 494 Days
• Field of Search: 600/300, 600/301, 600/481, 600/486, 600/500, 600/508, 600/423, 128/898, 128/900
• US Class Current: 600/300
• CPC Class Codes: A61B 5/02 Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02108 from analysis of pulse wave characteristics
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/681 Wristwatch-type devices

Abstract

A non-invasive device for evaluating circulatory state parameters, and specifically, a pulsewave analysis device capable of evaluation by separating blood vessel compliance and blood vessel resistance into central and peripheral components of the arterial system is provided. Microcomputer 4 detects the waveform at a test subject'"'"'s radius artery via pulsewave detector 1, and uptakes the stroke volume in the test subject which is measured by a stroke-volume measurer. Next, based on the measured stroke volume, microcomputer 4 adjusts the values of each element in a lumped five parameter model made up of an electrical circuit which models the arterial system from the center to the periphery of the body, so that the response waveform obtained when an electric signal corresponding to the pressure waveform at the proximal portion of the aorta in a test subject is provided to the electric circuit coincides with the waveform at the radius artery. Microcomputer 4 then outputs the thus-obtained values of each element as circulatory state parameters. In addition, microcomputer 4 calculates the diastolic pressure value, systolic pressure value and pulse waveform at the proximal portion of the aorta from the values of each element, and outputs the calculated result to output device 6.

Claims

1. A device for measuring a physiological state in an organism having an arterial system extending from a center portion of the organism'"'"'s body to a periphery thereof, said device comprising:

measuring means for measuring the physiological state on the basis of a pulse wave detected at a periphery of the arterial system; and

analysis means for calculating circulatory state parameters, including viscoelasticity of an aorta of the arterial system, based on the measured physiological state, to show a circulatory state of the arterial system from the center to the periphery.

2. A device according to claim 1, wherein the circulatory state parameters further include blood vessel resistance at the center of the arterial system due to blood viscosity, blood inertia at the center of the arterial system, blood vessel resistance at the periphery of the arterial system due to blood viscosity, and blood vessel viscoelasticity at the periphery of the arterial system.

3. A device according to claim 1, further comprising blood pressure calculating means for calculating a pressure waveform at the aorta based on the calculated circulatory state parameters.

4. A device according to claim 3, wherein the circulatory state parameters further include blood vessel resistance at the center of the arterial system due to blood viscosity, blood inertia at the center of the arterial system, blood vessel resistance at the periphery of the arterial system due to blood viscosity, and blood vessel viscoelasticity at the periphery of the arterial system.