MULTI-SENSOR ARRAY FOR MEASURING BLOOD PRESSURE

• US 20080312542A1
• Filed: 06/13/2008
• Published: 12/18/2008
• Est. Priority Date: 06/13/2007
• Status: Abandoned Application

• Current Assignee: Sotera Wireless Incorporated (Foxconn Technology Co., Ltd.)
• Original Assignee: Triage Wireless, Inc. (Foxconn Technology Co., Ltd.)
• Inventors: ZHOU, Zhou, VISSER, Henk II, HUNT, Kenneth R., BANET, Matthew J.
• Application Number:
  US12/139,219
• Publication Number:
  US 20080312542A1
• Time in Patent Office: Days
• US Class Current: 600/485
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06

Abstract

A sensor for monitoring a patient'"'"'s blood pressure, the sensor including a housing unit with a back surface and which includes: a pair of electrodes mounted on the back surface; an optical system mounted on the back surface and including at least one light source that emits optical radiation near 570 nm and at least one photodetector; a first amplifier which generates an analog electrical waveform from the electrical signals from the electrodes; a second amplifier that generates an analog optical waveform from the optical signal from the photodetector; analog-to-digital converter circuitry configured to receive the analog electrical waveform and generate a digital electrical waveform therefrom and to receive the analog optical waveform and generate a digital optical waveform therefrom; and a processor programmed to receive the digital electrical and optical waveforms and determine a pulse transit time for the patient which is a measure of a separation in time of a first feature of the digital electrical waveform and a second feature of the digital optical waveform and to use the pulse transit time to determine a blood pressure value for the patient.

Claims

1. A sensor for monitoring a patient'"'"'s blood pressure, the sensor comprising a housing unit configured to be worn on a patient'"'"'s arm, the housing unit having a back surface and comprising:

a pair of electrodes mounted on said back surface and positioned to contact the patient'"'"'s skin to generate electrical signals when the housing is worn on the patient'"'"'s arm;

an optical system mounted on said back surface and comprising at least one light source that emits optical radiation near 570 nm and at least one photodetector, wherein the at least one light source and the at least one photodetector are positioned to be adjacent to the patient'"'"'s skin when the housing is worn on the patient'"'"'s arm, wherein optical system is configured to generate an optical signal by detecting optical radiation emitted by the at least one light source and reflected from blood vessels underneath the patient'"'"'s skin;

a first amplifier configured to receive the electrical signals from the electrodes and generate an analog electrical waveform therefrom;

a second amplifier configured to receive the optical signal from the photodetector and generate an analog optical waveform therefrom;

analog-to-digital converter circuitry configured to receive the analog electrical waveform and generate a digital electrical waveform therefrom and to receive the analog optical waveform and generate a digital optical waveform therefrom; and

a processor programmed to receive the digital electrical and optical waveforms and determine a pulse transit time for the patient which is a measure of a separation in time of a first feature of the digital electrical waveform and a second feature of the digital optical waveform and to use the pulse transit time to determine a blood pressure value for the patient.

2. The sensor of claim 1, further comprising a short-range wireless transceiver configured to receive the blood pressure value for the patient and transmit it to a remote receiver.

3. The sensor of claim 1, further comprising an armband attached to the housing unit and for attaching the housing unit to the patient'"'"'s arm.

4. The sensor of claim 1, wherein the optical system comprises an array of optical modules mounted on said back surface and positioned to be adjacent to the patient'"'"'s skin when the housing is worn on the patient'"'"'s arm, wherein each optical module of the array of optical modules comprises a light source that emits optical radiation near 570 nm and a photodetector configured to generate an optical signal by detecting optical radiation emitted by the light source within that optical module and reflected from blood vessels underneath the patient'"'"'s skin and wherein the at least one light source and the at least one photodetector are among the light sources and photodetectors of the array.

5. The sensor of claim 1, wherein the optical modules are linearly arranged on said back surface.

6. The sensor of claim 1, wherein the optical modules are arranged in a circular pattern on said back surface.

7. A sensor for monitoring a patient'"'"'s blood pressure, the sensor comprising a housing unit configured to be worn on a patient'"'"'s arm, the housing comprising:

a pair of electrodes mounted on said back surface and positioned to contact the patient'"'"'s skin to generate electrical signals when the housing is worn on the patient'"'"'s arm;

an array of optical modules mounted on said back surface and positioned to be adjacent to the patient'"'"'s skin when the housing is worn on the patient'"'"'s arm, wherein each optical module of the array of optical modules comprises a light source that emits optical radiation near 570 nm and a photodetector configured to generate an optical signal by detecting optical radiation emitted by the light source within that optical module and reflected from blood vessels underneath the patient'"'"'s skin, wherein each optical module outputs on an output line an output signal that is derived from the optical signal in that optical module, wherein the output lines of the plurality of optical modules are all electrically connected to a common signal line to thereby produce a collective optical signal on the common signal line;

a first amplifier configured to receive the electrical signals from the electrodes and generate an analog electrical waveform therefrom;

a second amplifier configured to receive the collective optical signal from the collective signal line and generate an analog optical waveform therefrom;

analog-to-digital converter circuitry configured to receive the analog electrical waveform and generate a digital electrical waveform therefrom, and configured to receive the analog optical waveform and generate a digital optical waveform therefrom; and

a processor programmed to receive the digital electrical and optical waveforms and determine a pulse transit time for the patient which is a measure of a separation in time of a first feature of the digital electrical waveform and a second feature of the digital photodetector waveform and to use the pulse transit time to determine a blood pressure value for the patient.

8. The sensor of claim 7, wherein the collective optical signal is a sum of the output signals from the array of optical modules.

9. The sensor of claim 7, wherein the optical modules are linearly arranged on said back surface.

10. The sensor of claim 7, wherein the optical modules are arranged in a circular pattern on said back surface.

11. The sensor of claim 7, further comprising a short-range wireless transceiver configured to receive the blood pressure value for the patient and transmit it to a remote receiver.

12. The sensor of claim 7, further comprising an armband attached to the housing unit and for attaching the housing unit to the patient'"'"'s arm.