Sphygmomanometer utilizing optically detected arterial pulsation displacement

• US 6,106,478 A
• Filed: 01/13/1999
• Issued: 08/22/2000
• Est. Priority Date: 04/19/1995
• Status: Expired due to Term

• Current Assignee: A&D Company Limited
• Original Assignee: A&D Company Limited
• Inventors: Ishizuka, Shigehiro, Tochikubo, Osamu
• Primary Examiner(s): O'Connor, Cary
• Assistant Examiner(s): Natnithithadha, Navin
• Application Number:
  US08/983,144
• Time in Patent Office: 587 Days
• Field of Search: 600/481, 600/490, 600/493, 600/494, 600/495, 600/496, 600/499, 600/500, 600/501, 600/502, 600/310, 600/473, 600/477
• US Class Current: 600/494
• CPC Class Codes: A61B 5/02255 the pressure being controlled by plethysmographic signals, e.g. derived from optical sensors

Abstract

The invention relates to a sphygmomanometer capable of highly accurately judging the maximum blood pressure and minimum blood pressure, which has a cuff 10 which is attached to an appointed portion of a patient and presses the artery by supplying air therein; an optical range sensor 12 which is located opposite said cuff 10 and is able to detect the pulsation displacement of said artery; a digital processing section 14 which is able to judge the maximum and minimum blood pressure of said patient on the basis of photoelectric volumetric pulse wave signals sent out by said optical range sensor 12; and a display section 38 which is able to display the maximum and minimum blood pressure values judged by said digital data processing section 14. When increasing the pressure of the cuff 10 at a constant speed, said digital data processing section 14 is able to judge as the maximum blood pressure the point of disappearance of a photoelectric volumetric pulse wave signal and to judge as the minimum blood pressure the point of appearance of a flat section on the photoelectric volumetric pulse wave signal or its vicinity.

Claims

1. A sphygmomanometer comprising:

an inflatable cuff which is attached to a selected portion of a patient for applying pressure to an artery when inflated;

an optical range sensor which is located on opposite sides of said cuff for generating photoelectric volumetric pulse wave signals correlating to the pulsation displacement of said cuff caused by said artery;

a digital processing means for determining a maximum and minimum blood pressure of said patient solely on the basis of said photoelectric volumetric pulse wave signals generated by said optical range sensor; and

a display section for displaying the maximum and minimum blood pressure values determined by said digital data processing section,

wherein when raising or lowering an inflation pressure inside the cuff at a constant speed, said digital data processing section determines said maximum blood pressure by determining a point of disappearance or appearance of said photoelectric volumetric pulse wave signals, and determines said minimum blood pressure by determining a point at which said photoelectric volumetric pulse wave signals rapidly decrease.

2. A sphygmomanometer as defined in claim 1, wherein when raising or lowering the pressure inside the cuff at a constant speed, said digital data processing means determines a point of disappearance or appearance of said photoelectric volumetric pulse wave signals as the maximum blood pressure, and determines a point at which Korotoff'"'"'s sound constituents appear from said photoelectric volumetric pulse wave signals as the minimum blood pressure.

3. A sphygmomanometer as set forth in claim 1 or 2, wherein when raising or lowering the pressure inside the cuff at a constant speed, said digital data processing determines a point of disappearance or appearance of said photoelectric volumetric pulse wave signals as the maximum blood pressure, and determines a point, at which a vicinity of a flat section appears with respect to said photoelectric volumetric pulse wave signals as the minimum blood pressure.

4. A sphygmomanometer as set forth in claim 1, further including a plate for limiting the outer dimensions of the inflatable cuff.