BLOOD PRESSURE MEASURING APPARATUS AND METHOD FOR MEASURING BLOOD VESSEL ELASTICITY

• US 20110152699A1
• Filed: 12/21/2010
• Published: 06/23/2011
• Est. Priority Date: 12/21/2009
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: CHO, Jae-Geol
• Granted Patent: US 8,500,649 B2
• Time in Patent Office: Days
• US Class Current: 600/490
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]

Abstract

A blood pressure measuring method which can measure blood vessel elasticity, so that that the blood vessel elasticity can be commonly applied to all subjects, calculating pulse transit time at the time when no pressure is applied, calculating pulse transit time in an area where the pressure is changed by the cuff, and then calculating the elasticity of a blood vessel, using the pulse transit times.

Claims

1. A blood pressure measuring apparatus for measuring blood vessel elasticity, comprising:

a Pulse Wave Velocity (PWV) measuring module for measuring PWV, using an electrocardiogram signal and a pulse wave signal;

a blood pressure measuring module for measuring blood pressure by pressurizing or decompressing a cuff; and

a control unit, wherein the control unit calculates an initial pulse transit time, using the PWV at a time when the cuff is not pressurized, the control unit calculates pulse transit time in a pressure applied cuff area when the pressure is applied by the cuff, and the control unit calculates blood vessel elasticity, using the initial pulse transit time and the pulse transit time in the pressure applied cuff area.

2. The apparatus of claim 1, wherein the pulse transit measuring module comprises:

an electrocardiogram measuring signal for measuring the electrocardiogram signal; and

a pulse wave measuring unit for measuring the pulse wave signal.

3. The apparatus of claim 1, wherein the blood pressure measuring module comprises:

a cuff for pressurizing or decompressing an artery, the cuff being adapted to be wound on the upper part of an arm of a subject;

an air pump for pressurizing the cuff;

a pressure sensor for detecting pressure for pressurizing the cuff;

an analog-digital converter for converting a signal from the pressure sensor to an electric signal; and

a valve control unit for reducing the cuff pressure.

4. The apparatus of claim 1, wherein the initial pulse transit time is determined by dividing an arterial length from the heart to a pulse wave measuring point by the PWV, and Young'"'"'s modulus of the artery is substituted in the PWV.

5. The apparatus of claim 4, wherein the blood pressure in the cuff area corresponds to mean blood pressure minus the pressure applied by the cuff.

6. The apparatus of claim 4, wherein the arterial length is determined by practically measuring the length from the heart to the pulse wave measuring point.

7. The apparatus of claim 4, wherein the arterial length is determined through a regression equation, using the sex and height of a subject.

8. The apparatus of claim 5, wherein the control unit calculates a blood vessel elastic modulus as the Young'"'"'s modulus, using the initial pulse transmit time according to the mean blood pressure in an area corresponding to the arterial length, and the increment of pulse transmit time in the cuff area according to the blood pressure in the cuff area.

9. The apparatus of claim 8, wherein the blood vessel elastic modulus is expressed by,

10. A blood pressure measuring method for measuring blood vessel elasticity by a blood pressure measuring apparatus, comprising:

measuring Pulse Wave Velocity (PWV), using an electrocardiogram signal and a pulse wave signal;

measuring blood pressure by pressurizing or decompressing a cuff;

calculating an initial pulse transit time, using the PWV at a time when the cuff is not pressurized;

calculating pulse transit time in a pressure applied cuff area when the pressure is applied by the cuff; and

calculating blood vessel elasticity, using the initial pulse transit time and the pulse transit time in the pressure applied cuff area.

11. The method of claim 10, wherein the initial pulse transit time is determined by dividing an arterial length from the heart to a pulse wave measuring point by the PWV, and Young'"'"'s modulus of the artery is substituted for the PWV.

12. The method of claim 10, wherein the blood pressure in the cuff area corresponds to mean blood pressure minus the pressure applied by the cuff.

13. The method of claim 11, wherein the arterial length is determined by measuring the length from the heart to the pulse wave measuring point.

14. The method of claim 10, wherein the arterial length is determined through a regression equation, using the sex and height of a subject.

15. The method of claim 11, wherein calculating the blood vessel elasticity comprises:

calculating a blood vessel elastic modulus as the Young'"'"'s modulus, using the initial pulse transmit time according to the mean blood pressure in an area corresponding to the arterial length, and the increment of pulse transmit time in the cuff area according to the blood pressure in the cuff area.

16. The method of claim 15, wherein the elastic modulus of blood vessel is expressed by,