Method of positioning a sensor for determining blood pressure of an artery

• US 5,832,924 A
• Filed: 02/16/1995
• Issued: 11/10/1998
• Est. Priority Date: 02/16/1995
• Status: Expired due to Fees

• Current Assignee: Medwave, Inc.
• Original Assignee: Medwave, Inc.
• Inventors: Thede, Roger C., Curran, Timothy G., Poliac, Marius O., Archibald, G. Kent, Danielson, Orland H.
• Primary Examiner(s): Bahr, Jennifer
• Assistant Examiner(s): YARNELL, BRYAN KEITH
• Application Number:
  US08/389,826
• Time in Patent Office: 1,363 Days
• Field of Search: 128/672, 128/677, 128/680, 128/681, 128/682, 128/683, 128/690, 128/673, 128/687, 128/688
• US Class Current: 600/485
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 5/02116 of pulse wave amplitude A61B5/02225 takes precedence

Abstract

The present invention is a method for locating a sensor over an underlying artery having a blood pulse. The sensor is positioned at a plurality of locations above a known approximate location of the artery while applying a constant hold down pressure to the artery. The sensor is finally positioned at the location which exhibits the largest maximum pressure ampltiude.

Claims

1. A method of locating a sensor over an underlying artery having a blood pressure pulse, the method comprising:

positioning the sensor at a first one of a plurality of locations above a known approximate location of the artery while applying hold down pressure to the artery;

sensing a first maximum pressure amplitude exerted by the pulse during a first cardiac cycle in response to hold down pressure applied to the artery;

repositioning the sensor at a second one of the plurality of locations above the known approximate location of the artery while applying hold down pressure to the artery;

sensing a second maximum pressure amplitude exerted by the pulse during a second cardiac cycle in response to hold down pressure applied to the artery;

comparing the first sensed maximum pressure amplitude and the second sensed maximum pressure amplitude; and

positioning the sensor at one of the plurality of locations which exhibits the largest of the maximum pressure amplitudes.

2. The method of claim 1 including:

indicating maximum pressure amplitudes at each one of the plurality of locations so that the sensed maximum pressure amplitudes may be manually compared.

3. The method of claim 2 wherein indicating the maximum pressure amplitudes includes:

visually displaying the pressure exerted by the pulse upon the sensor as a function of time during an individual cardiac cycle.

4. The method of claim 3 wherein the pressure exerted by the pulse upon the sensor as a function of time is visually displayed on a monitor to aid in comparison of the sensed maximum pressure amplitudes and repositioning of the sensor at the location having the largest maximum pressure amplitude.

5. The method of claim 2 wherein indicating maximum pressure amplitudes includes:

providing a digital output indicating the maximum pressure amplitude.

6. The method of claim 1 wherein the pressure exerted by the pulse upon the sensor varies over time in the shape of a pressure waveform having a systolic portion and a diastolic portion during an individual cardiac cycle, wherein the diastolic portion has a known characteristic shape and wherein hold down pressure applied to the sensor is as large as possible without the known characteristic shape of the diastolic portion of the waveform distorting.

7. A method of locating a blood pressure sensor which includes an individual pressure transducer fluidly coupled to a fluid sensing chamber having an active sensing portion over an underlying artery, the method comprising:

positioning the active sensing portion of the fluid sensing chamber of the sensor at each of a plurality of locations above a known approximate location of the artery while applying hold down pressure at each location;

sensing pressure during a cardiac cycle with the sensor at each of the locations; and

displaying an indication of maximum pressure signal sensed during each cardiac cycle at each location to aid in final positioning of the sensor.

8. The method of claim 7 wherein the step of sensing pressure during a cardiac cycle includes:

continually sensing pressure during a cardiac cycle with the sensor at each of the locations.

9. A method of locating a sensor which includes an individual pressure transducer fluidly coupled to a fluid sensing chamber having an active sensing portion over an underlying artery having a blood pressure pulse, the method comprising:

positioning the active sensing portion of the fluid sensing chamber of the sensor at each one of a plurality of locations above a known approximate location of the artery while applying hold down pressure to the artery;

sensing waveform pressure data during a cardiac cycle at each one of the plurality of locations; and

positioning the sensor over the underlying artery based upon the sensed waveform pressure data at each one of the plurality of locations.

10. The method of claim 9 including:

providing an indicator based upon sensed waveform pressure data at each one of the plurality of locations to aid in final positioning of the sensor.

11. The method of claim 10 wherein providing an indicator includes:

deriving a value from the waveform pressure data at each of the plurality of locations; and

displaying the value at each of the plurality of locations.

12. The method of claim 11 wherein the value comprises a maximum pressure amplitude exerted by the pulse during a cardiac cycle in response to hold down pressure applied to the artery.

13. The method of claim 11 wherein displaying the value includes providing a digital output of the value.

14. The method of claim 10 wherein the pulse exerts a pressure upon the sensor which varies over time during an individual cardiac cycle and wherein providing an indicator includes:

visually displaying the pressure exerted by the pulse upon the sensor as a function of time during an individual cardiac cycle.

15. The method of claim 9 wherein the pulse exerts a pressure upon the sensor which varies over time in a shape of a pressure waveform having a systolic portion and a diastolic portion during an individual cardiac cycle, wherein the diastolic portion has a known characteristic shape and wherein the hold down pressure applied to the sensor is as large as possible without the known characteristic shape of the diastolic portion of the waveform distorting.

16. The method of claim 9 wherein the step of sensing waveform pressure data during a cardiac cycle at each one of the plurality of locations includes:

continually sensing waveform pressure data during a cardiac cycle at each one of the plurality of locations.

17. A method of locating a blood pressure sensor including an individual pressure transducer fluidly coupled to a fluid sensing chamber having an active sensing portion larger than an underlying artery over the underlying artery, the method comprising:

positioning the active sensing portion of the fluid sensing chamber at each of a plurality of locations above a known approximate location of the artery while applying hold down pressure at each location;

sensing a plurality of pressure amplitudes during an individual cardiac cycle exerted by the pulse upon the fluid sensing chamber at each one of the plurality of locations; and

positioning the fluid sensing chamber over the underlying artery based upon the plurality of sensed pressure amplitudes at each one of the plurality of locations.

18. The method of claim 17 including:

providing an indicator based upon the plurality of sensed pressure amplitudes at each one of the plurality of locations to aid in final positioning of the sensor.

19. The method of claim 18 wherein providing an indicator includes:

deriving a value from a plurality of sensed pressure amplitudes at each one of the plurality of locations; and

displaying the value at each of the plurality of locations.

20. The method of claim 19 wherein the value comprises a maximum pressure amplitude exerted by the pulse during an individual cardiac cycle at each of the plurality of locations.

21. The method of claim 19 wherein displaying the value includes providing a digital output of the value.

22. The method of claim 18 wherein providing an indicator includes:

visually displaying a plurality of sensed pressure amplitudes as a function of time during an individual cardiac cycle.