Heart Pulse Detection

• US 20110245697A1
• Filed: 03/24/2011
• Published: 10/06/2011
• Est. Priority Date: 03/31/2010
• Status: Active Grant

• Current Assignee: Polar Electro Oy
• Original Assignee: Polar Electro Oy
• Inventors: Miettinen, Jari
• Granted Patent: US 9,173,578 B2
• Time in Patent Office: Days
• US Class Current: 600/500
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/6814 Head
• CPC Class Codes: A61B 5/6824 Arm or wrist
• CPC Class Codes: A61B 5/6828 Leg
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/7214 using signal cancellation, e.g. based on input of two identical physiological sensors spaced apart, or based on two signals derived from the same sensor, for different optical wavelengths
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence

Abstract

There is provided an apparatus for determining a heart pulse of a person, the apparatus comprising at least two detectors configured to detect a blood pulse optically from the blood circulation of the person and to be placed optically on the skin of the person such that the detection of the blood pulse by each of the at least two detectors is expected to take place in a known order, a processor configured to determine that the detection of the blood pulse is correct when the detection of the blood pulse by each of the at least two detectors takes place in the known order, and to determine the heart pulse of the person on the basis of the detected pulses that are determined as correct.

Claims

1. An apparatus for determining heart pulses of a person, the apparatus comprising:

at least two detectors configured to detect a blood pulse optically from the blood circulation of the person and to be placed optically on the skin of the person; and

a processor configured to determine that the blood pulse has been detected when the detections by the at least two detectors take place in a known order, the processor being configured to determine the heart pulse of the person on the basis of the detected blood pulse.

2. The apparatus of claim 1, wherein the processor is further configured to determine that the blood pulse has been detected when the detections by the at least two detectors are separated by known time differences.

3. The apparatus of claim 1, wherein the at least two detectors are further configured to detect a variation in optical radiation reflected from the human tissue in order to detect the blood pulse from the blood circulation optically, wherein the detection of the blood pulse comprises obtaining knowledge of at least one of the following:

a time instant, form and phase of a blood pulse waveform.

4. The apparatus of claim 3, wherein the apparatus further comprises at least one optical radiation source configured to provide optical radiation such that the at least two detectors are able to detect the optical radiation reflected from the human tissue.

5. The apparatus of claim 3, further comprising a signal processing chain connected to the at least two detectors and configured to be sensitive enough to enable the detection of the blood pulse optically when the reflected optical radiation to be detected originates from ambient optical radiation only.

6. The apparatus of claim 1, wherein the at least two detectors are further configured to detect the blood pulse from at least one of the following:

the arterial blood flow, the venous blood flow, and the microcirculation, of the person.

7. The apparatus of claim 1, wherein the processor and the at least two detectors are comprised in a wrist device.

8. The apparatus of claim 7, wherein the apparatus further comprises at least one optical radiation guide embodied in at least one wrist band and configured to convey the optical radiation to an area of the skin such that the at least two detectors are able to detect the reflected optical radiation.

9. The apparatus of claim 1, further comprising a gauge unit equipped with the at least two detectors, the at least one light source, and a transmitter configured to transmit detection results to a main unit equipped with the processor.

10. The apparatus of claim 1, further comprising a further detector configured to detect the blood pulse optically and to be placed optically on the skin of the person, wherein the processor is further configured to determine that the blood pulse has been detected when the detection of the blood pulse by the further detector takes place substantially at the same time as the detection of the blood pulse by a reference detector being one of the at least two detectors.

11. The apparatus of claim 10, wherein the further detector is configured to be placed optically on a side of the wrist opposite to the one of the at least two detectors.

12. The apparatus of claim 1, wherein the optical radiation is provided at two different wavelengths, the processor being further configured to determine an oxygen saturation level from the detected blood pulse by comparing the amount of the detected reflected optical radiation having different wavelengths.

13. The apparatus of claim 1, wherein the processor is further configured to correlate the reflected optical radiation signals detected by the at least two detectors in order to verify the presence of a blood pulse.

14. The apparatus of claim 1, wherein the processor is further configured to allow for calibration of at least one of the following:

the known order of the blood pulse detections with respect to the person and the known time difference between the blood pulse detections with respect to the person.