Method and device for monitoring blood pressure

• US 20030004421A1
• Filed: 07/09/2002
• Published: 01/02/2003
• Est. Priority Date: 10/09/2000
• Status: Active Grant

• Current Assignee: HealthSTATS International Pte Ltd.
• Original Assignee: HealthSTATS International Pte Ltd.
• Inventors: Ting, Choon Meng, Chua, Ngak Hwee
• Granted Patent: US 6,918,879 B2
• 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 5/02116 of pulse wave amplitude A61B5/02225 takes precedence
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/681 Wristwatch-type devices

Abstract

A device for continuously monitoring a user'"'"'s arterial blood pressure has a sensor adapted to continuously detect the blood pressure and to generate signals representative thereof by contact with an external surface of the user'"'"'s body at a location adjacent an artery. The sensor is securely held in operable contact with the user'"'"'s body at the location. A microprocessor interprets the signals generated by the sensor to determine the actual arterial blood pressure. The sensor includes a projecting portion for detecting and transmitting changes in blood pressure, wherein the projecting portion is adapted to effect at least partial occlusion of the artery at the location.

Claims

1. A device for non-invasive continuous monitoring of a user'"'"'s arterial blood pressure that is capable of being used as an ambulatory beat-to-beat blood pressure monitor (ABMP) including,

sensor means adapted to continuously detect said blood pressure and to generate signals representative thereof by contact with an external surface of the user'"'"'s body at a location adjacent an artery;

microprocessor means for interpreting said signals generated by the sensor means to determine actual arterial blood pressure;

wherein the microprocessor is programmed to record a complete and continuous arterial pulse waveform.

2. The device as claimed in claim 1 wherein the sensor means includes a pressure transducer that provides electrical output signal corresponding to an exerted pressure by pulsation of the artery.

3. A device as claimed in claim 1 wherein said microprocessor is programmed to detect at least the dicrotic notch and the diastolic trough within a continuous arterial pulse waveform.

4. A device as claimed in claim 3 wherein said microprocessor is programmed to calculate a mean diastolic pressure as the mean sensed pressure between a said detected dicrotic notch and the immediately following diastolic trough.

5. A device as claimed in claim 4 wherein said microprocessor is programmed to calculate a mean arterial pressure as the average pressure between two consecutive said diastolic troughs, and to calculate a mean diastolic pressure index as the quotient of the calculated mean diastolic pressure divided by the mean arterial pressure.

6. A device as claimed in claim 3 wherein said microprocessor is programmed to calculate a mean systolic pressure as the average pressure between a diastolic trough and the immediately subsequent dicrotic notch.

7. A device as claimed in claim 4 wherein said microprocessor is programmed to calculate a mean arterial pressure as the average pressure between two consecutive said diastolic troughs, and to calculate a mean systolic pressure index as the quotient of the calculated mean systolic pressure divided by the mean arterial pressure.

8. A device as claimed in claim 1 wherein said microprocessor is programmed to detect the peak systolic pressure and record the peak systolic pressure for at least a selection of recorded arterial pulses and to detect the diastolic trough and record a pressure at the diastolic trough for each pulse of said at least selection of arterial pulses.

9. A device as claimed in claim 8 wherein said device includes an alarm and said microprocessor is programmed to operate said alarm in response to an indicator falling outside a preselected range, said indicator being selected from:

said systolic peak pressure, said diastolic trough pressure or the difference between said systolic peak pressure.

10. A device as claimed in claim 9 wherein said device includes user input means, and said microprocessor is programmed to allow setting or selection of a threshold for said indicator.

11. A device as claimed in claim 8 wherein said microprocessor is programmed to calculate an average systolic pressure as the average of the said pressure as recorded at said systolic peak for said at least selection of arterial pulses and an average diastolic pressure as the average pressure recorded at said diastolic trough for said at least selection of arterial pulses.

12. A device as claimed in claim 2 wherein a calibrator which measures the user'"'"'s blood pressure by occluding an artery of the user and obtaining an absolute diastolic and systolic reading of the user'"'"'s arterial blood pressure is operatively connectable to the device and said processor is programmed to calculate calibration constants from comparisons of said absolute readings and said sensor signals for ongoing calculation of pressure from said sensor signals.

13. A device as claimed in claim 1 including a first housing holding said sensor and a second housing enclosing said microprocessor, and at least one strap connecting said first housing and said second housing and together therewith forming a band to encircle the wrist of a wearer, said first housing having an outwardly facing pressure surface, with at least one said strap passing freely over said pressure surface.

14. A device as claimed in claim 13 wherein said straps include a second strap connecting between said first and second housing and a third strap connected with said second housing and said elastic strap, said elastic strap being connected at one end to said first housing, extending there from to said third strap before turning back upon itself to form a loop, said loop being connected to said third strap, to then pass over said pressing surfaces of said first housing, with the other end of said elastic strap being connected to said second housing or to said second strap.

15. A device as claimed in claim 13 including a joining ring, said elastic strap passing through said joining ring at said loop, and said third strap passing through said joining ring and back upon itself to hold said joining ring within a loop thereof, said third strap including adjustable connection means operating between said in and outer portions.

16. A device as claimed in claim 13 including a padding cuff disposed within said band, said padding cuff including an aperture, said sensor including a plunger protruding from said first housing through said aperture, and said cuff being adhered to an inner face of said first housing.

18. A method as claimed in claim 17 including calculating a mean diastolic pressure as the mean recorded pressure between a said detected dicrotic notch and the immediately following diastolic trough.

19. A method as claimed in claim 18 including calculating a mean arterial pressure as the average pressure between two consecutive said diastolic troughs, and calculating a mean diastolic pressure index as the quotient of the calculated mean diastolic pressure divided by the mean arterial pressure.

20. A method as claimed in claim 19 including calculating a mean systolic pressure as the average pressure between a diastolic trough and the immediately subsequent dicrotic notch.

21. A method as claimed in claim 20 including calculating a mean arterial pressure as the average pressure between two consecutive diastolic troughs, and calculating a mean systolic pressure index as the quotient of the calculated mean systolic pressure divided by the mean arterial pressure.

17. A method for continuous monitoring of a user'"'"'s arterial blood pressure including the steps of:

recording a complete and continuous arterial pulse pressure waveform,

locating at least the dicrotic notch and the diastolic trough within said continuous arterial pulse waveform, and

calculating at least one parameter using said waveform and said diastolic trough and dicrotic notch locations.