Electronic blood pressure meter

• US 4,862,895 A
• Filed: 08/17/1988
• Issued: 09/05/1989
• Est. Priority Date: 04/12/1985
• Status: Expired due to Term

• Current Assignee: Omron Tateisi Electronics Co. (Omron Corporation)
• Original Assignee: Omron Tateisi Electronics Co. (Omron Corporation)
• Inventors: Yamakoshi, Kenichi, Shimazu, Hideaki, Yamasawa, Tsutomu
• Primary Examiner(s): JAWORSKI, FRANCIS J
• Application Number:
  US07/233,909
• Time in Patent Office: 384 Days
• Field of Search: 128/667
• US Class Current: 600/493
• CPC Class Codes: A61B 5/02241 of small dimensions, e.g. adapted to fingers
• CPC Class Codes: A61B 5/02255 the pressure being controlled by plethysmographic signals, e.g. derived from optical sensors

Abstract

Disclosed is an electronic blood pressure meter which is adapted to measure blood pressure from a finger. A cuff for applying pressure to the finger comprises a plurality of chambers which are communicated to each other and, thereby, provides a sufficient flexibility to closely conform to the contour of the finger. A sensor for detecting pulse wave data may be conveniently place on the inner surface of the cuff and is adapted to detect the reflection of light by an artery. Further, an air buffer can increase the effective air volume of the cuff and can reduce the rate of the pressure drop of the air cuff for a given rate of air vent from the cuff. By deriving the pulse wave data and computing the systolic and diastolic blood pressure therefrom in the course of increasing the air pressure of the cuff, the discomfort to the patient whose blood pressure is to measured can be substantially reduced.

Claims

1. An electronic blood pressure meter for measuring blood pressure, comprising:

a cuff means of flexible material and defining at least one air chamber therein for applying air pressure to a finger inserted in a cylindrical space defined by an inner surface of the cuff means;

pressure control means connected to the at least one air chamber defined in the cuff means for varying the air pressure inside the cuff means;

a cuff pressure sensor means for detecting the air pressure in the at least one air chamber of the cuff means;

plethysmographic pulse wave information detecting means having a plurality of elements directly and openly mounted and fixed close to each other on the inner surface of the cuff means for direct contact with the finger for detecting pulse wave information as the air pressure in the at least one air chamber of the cuff means is varied, said cuff means having a pre-formed depression in an inner surface thereof which is adapted to receive said elements such that said inner surface presented by the cuff means and the detecting means and encircling the finger remains smooth and even while the cuff means is inflated and encircling the finger during measurement; and

blood pressure determination means for determining a blood pressure value from the cuff air pressure detected by the cuff pressure sensor means and the pulse wave information detected by the pulse wave information detecting means.

2. An electronic blood pressure meter as defined in claim 1, wherein the pressure control means comprises an air pump, a fast vent valve and a slow vent valve all operably coupled to the cuff means.

3. An electronic blood pressure meter as defined in claim 2, wherein the air pump, the fast vent valve and a slow vent valve are operably connected to the cuff means by a common conduit.

4. An electronic blood pressure meter as defined in claim 3, wherein an air buffer means for accumulating air is connected to the common conduit.

5. An electronic blood pressure meter as defined in claim 4, wherein the cuff and the fast vent valve are connected to a first common conduit, and the air pump and another fast vent valve are connected to a second common conduit, wherein the first and the second common conduits are being connected to each other by way of the slow vent valve.

6. An electronic blood pressure meter as defined in claim 5, wherein the air pressure control means provides air pressure inside the cuff for gradually increasing while the pulse wave information is detected by the pulse wave information detecting means.

7. An electronic blood pressure meter as defined in claim 3, wherein the air pressure control means provides air pressure inside the cuff means for gradually decreasing while the pulse wave information is detected by the pulse wave information detecting means.

8. An electronic blood pressure meter as defined in claim 5, wherein an air buffer is connected to the second common conduit.