Noninvasive continuous blood pressure measuring apparatus and a method of noninvasively measuring continuous blood pressure

• US 6,358,212 B1
• Filed: 04/13/1999
• Issued: 03/19/2002
• Est. Priority Date: 04/20/1998
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Hagiwara, Hisashi, Hasegawa, Kinya, Nishimura, Yushi
• Primary Examiner(s): Nasser, Robert L.
• Application Number:
  US09/290,394
• Time in Patent Office: 1,071 Days
• Field of Search: 600/485, 600/400, 600/493-6, 600/500-503
• US Class Current: 600/485
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 2562/043 in a linear array
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02116 of pulse wave amplitude A61B5/02225 takes precedence
• CPC Class Codes: A61B 5/02133 by using induced vibration of the blood vessel

Abstract

One of pairs of an exciter and a sensor is selected in accordance with the detection signal which is derived from an exciter waveform induced in an artery transmitted therethrough. The pairs of exciters and sensors are arranged on a substrate in various formations. A/D converters are provided to respective detection signals. A frequency of the oscillation signal supplied to the exciter is controlled by various oscillation signal generation circuits. Bandpass filtering for extracting the exciter waveform, low-pass-filtering for extracting a natural blood pressure waveform, phase difference detection processes are provided by a microprocessor, wherein the bandpass filtering and low-pass-filtering processes may be replaced with a bandpass filter and a low pass filter, and their outputs are selected by a switching circuit and supplied to the microprocessor through one a/d converter. The frequency of the oscillation signal is controlled to an optimum frequency by detecting the detection signal and estimating the attenuation, dispersion, phase shift with respect to different frequency and by determining one of the different frequency in accordance with the estimation result. The waveform of the oscillation signal is controlled to an optimum waveform similarly.

Claims

1. A noninvasive continuous blood pressure measuring apparatus comprising:

oscillating means for generating an oscillation signal having a desired frequency and a desired amplitude;

a substrate;

a plurality of exciters arranged on said substrate in a direction responsive to said oscillation signal for inducing exciter waveforms in an artery and blood in said artery of a living body;

a plurality of sensors respectively arranged on said substrate in said direction of predetermined distance apart from said exciters for receiving induced exciter waveforms transmitted through said artery from said living body and outputting detection signals;

switching means for effecting recurrently switching and time-divisionally outputting outputs of said sensors;

determining and selecting means responsive to said switching means for determining one of said sensor outputs in accordance with an output of said switching means and a predetermined judging condition and for selecting and outputting said one of said sensor outputs;

calibration hemadynamometer means for detecting absolute values of a maximum blood pressure and a minimum blood pressure of said living body;

calculating means for receiving said absolute values from said hemadynamometer means and successively calculating and outputting an instantaneous blood pressure value from a phase relation between said oscillation signal and said one of said outputs from said determining and selecting means and said absolute values;

displaying means for displaying a continuous blood pressure variation from said instantaneous blood pressure successively outputted by said calculation means;

wherein said substrate correspondingly arranges said exciters and said sensors such that pairs, each of which includes an exciter and a sensor, are arranged in said direction and said exciter and said sensor of each pair are arranged in a second direction perpendicular to said direction; and

attaching means for attaching said substrate to said living body.

3. The noninvasive continuous blood pressure measuring apparatus as claimed in claim 1, further comprising:

a plurality of a/d converters for respectively a/d-converting said detection signals and supplying converted signals to said determining and selecting means as said outputs of said sensors.

2. A noninvasive continuous blood pressure measuring apparatus comprising:

oscillating means for generating an oscillation signal having a desired frequency and a desired amplitude;

a substrate;

a plurality of exciters arranged on said substrate in a direction responsive to said oscillation signal for inducing exciter waveforms in an artery and blood in said artery of a living body;

a plurality of sensors respectively arranged on said substrate in said direction of predetermined distance apart from said exciters for receiving induced exciter waveforms transmitted through said artery from said living body and outputting detection signals;

switching means for effecting recurrently switching and time-divisionally outputting outputs of said sensors;

determining and selecting means responsive to said switching means for determining one of said sensor outputs in accordance with an output of said switching means and a predetermined judging condition and for selecting and outputting said one of said sensor outputs;

calibration hemadynamometer means for detecting absolute values of a maximum blood pressure and a minimum blood pressure of said living body;

calculating means for receiving said absolute values from said hemadynamometer means and successively calculating and outputting an instantaneous blood pressure value from a phase relation between said oscillation signal and said one of said outputs from said determining and selecting means and said absolute values;

displaying means for displaying a continuous blood pressure variation from said instantaneous blood pressure successively outputted by said calculation means;

wherein said substrate correspondingly arranging said exciters and said sensors such that groups include two of said sensors and one of said exciters, the exciter of each group arranged between two of said sensors of the group with said predetermined distance between an exciter and the two sensors of each group, the groups being arranged along said direction; and

attaching means for attaching said substrate to said living body.

4. The noninvasive continuous blood pressure measuring apparatus as claimed in claim 2, further comprising:

a plurality of a/d converters for respectively a/d-converting said detection signals and supplying converted signals to said determining and selecting means as said