CUFF INTEGRITY DETECTION DURING INFLATION OF AN AUTOMATED BLOOD PRESSURE DEVICE

• US 20120245478A1
• Filed: 03/21/2011
• Published: 09/27/2012
• Est. Priority Date: 03/21/2011
• Status: Active Grant

• Current Assignee: Welch Allyn Incorporated
• Original Assignee: Welch Allyn Incorporated
• Inventors: Whitaker, Tyson B., Kinsley, Matthew J., Buchanan, Joseph D.
• Granted Patent: US 8,911,378 B2
• Time in Patent Office: Days
• US Class Current: 600/499
• CPC Class Codes: A61B 2560/0276 Determining malfunction
• CPC Class Codes: A61B 2560/0475 Special features of memory means, e.g. removable memory cards
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/0225 the pressure being controlled by electric signals, e.g. derived from Korotkoff sounds
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence

Abstract

A method for detecting cuff slippage in a blood pressure monitoring device includes starting a cuff inflation on the blood pressure monitoring device. A plurality of pressure samples is obtained when the cuff is inflating. A level of background noise is determined during the cuff inflation. The level of background noise is determined from the plurality of pressure samples. When the background noise is determined, a determination is made from the plurality of blood pressure readings whether a pressure pattern indicating cuff slippage is obtained.

Claims

1. A method for determining cuff slippage in a blood pressure monitoring device, the method comprising:

on the blood pressure monitoring device, starting a cuff inflation including inflating a blood pressure cuff;

obtaining a plurality of pressure samples when the cuff is inflating;

determining whether a slope corresponding to the plurality of pressure samples is a positive number;

when it is determined that the slope is a positive number, determining a level of background noise during the cuff inflation, the level of background noise being determined from the plurality of pressure samples; and

when the background noise is determined,

determining from the plurality of pressure samples whether a pressure pattern indicating cuff slippage is obtained.

2. The method of claim 1, wherein determining whether the slope corresponding to the plurality of pressure samples is a positive number comprises:

obtaining a subset of the plurality of pressure samples;

obtaining a first pressure sample from the subset of the plurality of pressure samples, the first pressure sample being a lowest pressure in the subset of the plurality of pressure samples;

obtaining a second pressure sample from subset of the plurality of pressure samples, the second pressure sample being a highest pressure in the subset of the plurality of pressure samples;

calculating the slope, the calculation of the slope comprising;

subtracting the first pressure sample from the second pressure sample;

dividing a result of the subtraction of the first pressure sample from the second pressure sample by the number of pressure samples in the subset of the plurality of pressure samples; and

when the slope is greater than zero, making a determination that the slope is a positive number.

3. The method of claim 1, wherein determining the level of background noise during the cuff inflation comprises:

obtaining a subset of the plurality of pressure samples;

obtaining a first pressure sample from the subset of the plurality of pressure samples, the first pressure sample being a lowest pressure in the subset of the plurality of pressure samples;

obtaining a second pressure sample from subset of the plurality of pressure samples, the second pressure sample being a highest pressure in the subset of the plurality of pressure samples;

calculating a slope, the calculation of the slope comprising;

subtracting the first pressure sample from the second pressure sample; and

dividing a result of the subtraction of the first pressure sample from the second pressure sample by the number of pressure samples in the subset of the plurality of pressure samples;

determining a maximum pressure sample above the calculated slope;

determining a maximum pressure sample below the calculated slope; and

subtracting the maximum pressure sample below the calculated slope from the maximum pressure sample above the calculated slope, the result of the subtraction being designated as the level of background noise.

4. The method of claim 3, wherein the number of pressure samples in the subset of the plurality of pressure samples is seven.

5. The method of claim 1, wherein determining from the plurality of pressure samples whether a pressure sample pattern indicating slippage is obtained comprises determining whether the plurality of pressure samples includes a 4-point “

V”

pattern.

6. The method of claim 1, wherein determining from the plurality of pressure samples whether a pressure sample pattern indicating cuff slippage is obtained comprises:

obtaining the last pressure sample in the plurality of pressure samples;

obtaining the first from last pressure sample in the plurality of pressure samples;

obtaining the second from last pressure sample in the plurality of pressure samples;

obtaining the third from last pressure sample in the plurality of pressure samples;

determining whether the third from last pressure sample is greater than the sum of the second from the last pressure sample and the product of 1.5 multiplied by the level of background noise;

determining whether the last pressure sample is greater than the sum of the first from last pressure sample and the product of 1.5 multiplied by the level of background noise; and

when it is determined that the third from last pressure sample is greater than the sum of the second from last pressure sample and the product of 1.5 multiplied by the level of background noise and when it is determined that the last pressure sample is greater than the sum of the first from last pressure sample and the product of 1.5 multiplied by the level of background noise, making a determination that a cuff slippage condition exists.

7. The method of claim 1, wherein determining from the plurality of pressure samples whether a pressure sample pattern indicating cuff slippage is obtained comprises:

determining whether the plurality of pressure samples includes a 5-point “

V”

pattern.

8. The method of claim 1, wherein determining from the plurality of pressure samples whether a pressure sample pattern indicating cuff slippage is obtained comprises:

obtaining the last pressure sample in the plurality of pressure samples;

obtaining the first from last pressure sample in the plurality of pressure samples;

obtaining the second from last pressure sample in the plurality of pressure samples;

obtaining the third from last pressure sample in the plurality of pressure samples;

obtaining the fourth from last pressure sample in the plurality of pressure samples;

determining whether the fourth from the last pressure sample is greater than the sum of the third from the last pressure sample and the product of 1.5 multiplied by the level of background noise;

determining whether the last pressure sample is greater than the sum of the first from the last pressure sample and the product of 1.5 multiplied by the level of background noise;

determining whether the second from the last pressure sample is less than the third from the last pressure sample;

determining whether the second from the last pressure sample is less than the first from the last pressure sample; and

when it is determined that the fourth from the last pressure sample is greater than the sum of the third from the last pressure sample and the product of 1.5 multiplied by the level of background noise and when it is determined that the last pressure sample is greater than the sum of the first from last pressure sample and the product of 1.5 multiplied by the level of background noise and when it is determined that the second from the last pressure sample is less than the third from the last pressure sample and when it is determined that the second from the last pressure sample is less than the first from the last pressure sample, making a determination that a cuff slippage condition exists.

9. The method of claim 1, wherein determining from the plurality of pressure samples whether a pressure pattern indicating slippage is obtained comprises

determining whether a pressure drop of greater than 2.25 multiplied by the level of background noise occurs for two successive pressure samples.

10. The method of claim 1, wherein determining from the plurality of pressure samples whether a pressure pattern indicating slippage is obtained comprises:

obtaining the last pressure sample in the plurality of pressure samples;

obtaining the first from last pressure sample in the plurality of pressure samples;

obtaining the second from last pressure sample in the plurality of pressure samples;

determining whether the second from last pressure sample is greater than the sum of the first from last pressure sample and the product of 2.25 multiplied by the level of background noise;

determining whether the first from last pressure sample is greater than the sum of the last pressure sample and the product of 2.25 multiplied by the level of background noise; and

when it is determined that the second from last pressure sample is greater than the sum of the first from last pressure sample and the product of 2.25 multiplied by the level of background noise and when it is determined that the first from last pressure sample is greater than the sum of the last pressure sample and the product of 2.25 multiplied by the level of background noise, making a determination that a cuff slippage condition exists.

11. The method of claim 1, wherein the plurality of pressure samples is obtained after a minimum pressure is reached.

12. An electronic computing system comprising:

a processing unit; and

a data storage system, the data storage system storing instructions that, when executed by the processing unit, cause the electronic computing system to;

start a cuff inflation, the cuff inflation comprising inflating the blood pressure cuff and obtaining a plurality of pressure samples when the cuff is inflating;

determine whether a slope corresponding to the plurality of pressure samples is a positive number;

when it is determined that the slope is a positive number, determine a level of background noise during the cuff inflation, the level of background noise being determined from the plurality of pressure samples; and

when the background noise is determined,

determine from the plurality of pressure samples whether a pressure pattern indicating cuff slippage is obtained.

13. The electronic computing system of claim 12, wherein determining whether the slope corresponding to the plurality of pressure samples is a positive number comprises:

obtaining a subset of the plurality of pressure samples;

obtaining a first pressure sample from the subset of the plurality of pressure samples, the first pressure sample being a lowest pressure in the subset of the plurality of pressure samples;

obtaining a second pressure sample from subset of the plurality of pressure samples, the second pressure sample being a highest pressure in the subset of the plurality of pressure samples;

calculating the slope, the calculation of the slope comprising;

subtracting the first pressure sample from the second pressure sample; and

dividing a result of the subtraction of the first pressure sample from the second pressure sample by the number of pressure samples in the subset of the plurality of pressure samples; and

when the slope is greater than zero, making a determination that the slope is a positive number.

14. The electronic computing system of claim 12, wherein determining the level of background noise during the cuff inflation comprises:

obtaining a subset of the plurality of pressure samples;

obtaining a first pressure sample from the subset of the plurality of pressure samples, the first pressure sample being a lowest pressure in the subset of the plurality of pressure samples;

obtaining a second pressure sample from subset of the plurality of pressure samples, the second pressure sample being a highest pressure in the subset of the plurality of pressure samples;

calculating a slope, the calculation of the slope comprising;

subtracting the first pressure sample from the second pressure sample; and

dividing a result of the subtraction of the first pressure sample from the second pressure sample by the number of pressure samples in the subset of the plurality of pressure samples;

determining a maximum pressure sample below the calculated slope; and

subtracting the maximum pressure sample below the calculated slope from the maximum pressure sample above the calculated slope, the result of the subtraction being designated as the level of background noise.

15. The electronic computing system of claim 12, wherein determining from the plurality of pressure samples whether a pressure sample pattern indicating cuff slippage is obtained comprises:

obtaining the last pressure sample in the plurality of pressure samples;

obtaining the first from last pressure sample in the plurality of pressure samples;

obtaining the second from last pressure sample in the plurality of pressure samples;

obtaining the third from last pressure sample in the plurality of pressure samples;

determining whether the third from the last pressure sample is greater than the sum of the second from the last pressure sample and the product of 1.5 multiplied by the level of background noise;

determining whether the last pressure sample is greater than the sum of the first from the last pressure sample and the product of 1.5 multiplied by the level of background noise; and

when it is determined that the third from the last pressure sample is greater than the sum of the second from the last pressure sample and the product of 1.5 multiplied by the level of background noise and when it is determined that the last pressure sample is greater than the sum of the first from last pressure sample and the product of 1.5 multiplied by the level of background noise, making a determination that a cuff slippage condition exists.

16. The electronic computing system of claim 12, wherein determining from the plurality of pressure samples whether a pressure pattern indicating cuff slippage is obtained comprises:

obtaining the last pressure sample in the plurality of pressure samples;

obtaining the first from last pressure sample in the plurality of pressure samples;

obtaining the second from last pressure sample in the plurality of pressure samples;

obtaining the third from last pressure sample in the plurality of pressure samples;

obtaining the fourth from last pressure sample in the plurality of pressure samples;

determining whether the fourth from the last pressure sample is greater than the sum of the third from the last pressure sample and the product of 1.5 multiplied by the level of background noise;

determining whether the last pressure sample is greater than the sum of the first from the last pressure sample and the product of 1.5 multiplied by the level of background noise;

determining whether the second from the last pressure sample is less than the third from the last pressure sample;

determining whether the second from the last pressure sample is less than the first from the last pressure sample; and

when it is determined that the fourth from the last pressure sample is greater than the sum of the third from the last pressure sample and the product of 1.5 multiplied by the level of background noise and when it is determined that the last pressure sample is greater than the sum of the first from last pressure sample and the product of 1.5 multiplied by the level of background noise and when it is determined that the second from the last pressure sample is less than the third from the last pressure sample and when it is determined that the second from the last pressure sample is less than the first from the last pressure sample, making a determination that a cuff slippage condition exists.

17. The electronic computing system of claim 12, wherein determining from the plurality of pressure samples whether a pressure pattern indicating slippage is obtained comprises:

obtaining the last pressure sample in the plurality of pressure samples;

obtaining the first from last pressure sample in the plurality of pressure samples;

obtaining the second from last pressure sample in the plurality of pressure samples;

determining whether the second from the last pressure sample is greater than the sum of the first from the last pressure sample and the product of 2.25 multiplied by the level of background noise;

determining whether the first from the last pressure sample is greater than the sum of the last pressure sample and the product of 2.25 multiplied by the level of background noise; and

when it is determined that the second from the last pressure sample is greater than the sum of the first from the last pressure sample and the product of 2.25 multiplied by the level of background noise and when it is determined that the first from the last pressure sample is greater than the sum of the last pressure sample and the product of 2.25 multiplied by the level of background noise, making a determination that a cuff slippage condition exists.

18. The electronic computing system of claim 12, wherein when more than 10 slippage conditions occur, taking a form of action, the form of action comprising initiating a cuff deflation cycle and setting an alert for a user to alert the user to the slippage condition

19. A computer-readable data storage medium comprising instructions that, when executed by a processing unit of a computing device, cause the computing device to:

start a cuff inflation, the cuff inflation comprising inflating the blood pressure cuff and obtaining a plurality of pressure samples when the cuff is inflating;

determine whether a slope corresponding to the plurality of pressure samples is a positive number, the determination of whether the slope corresponds to a positive number comprising;

obtaining a subset of the plurality of pressure samples;

obtaining a first pressure sample from the subset of the plurality of pressure samples, the first pressure sample being a lowest pressure in the subset of the plurality of pressure samples;

obtaining a second pressure sample from subset of the plurality of pressure samples, the second pressure sample being a highest pressure in the subset of the plurality of pressure samples;

calculating the slope, the calculation of the slope comprising;

subtracting the first pressure sample from the second pressure sample; and

dividing a result of the subtraction of the first pressure sample from the second pressure sample by the number of pressure samples in the subset of the plurality of pressure samples; and

when the slope is greater than zero, making a determination that the slope is a positive number;

when it is determined that the slope is a positive number, determine a level of background noise during the cuff inflation, the level of background noise being determined from the plurality of pressure samples, the determination of the level of background noise during the cuff inflation comprising;

determining a maximum pressure sample above the calculated slope;

determining a maximum pressure sample below the calculated slope; and

subtracting the maximum pressure sample below the calculated slope from the maximum pressure sample above the calculated slope, the result of the subtraction being designated as the level of background noise; and

when the background noise is determined, determine from the plurality of pressure samples whether a pressure pattern indicating cuff slippage is obtained, the pressure pattern indicating cuff slippage being a 4-point “

V”

pattern, the determination of whether the pressure pattern indicating slippage is obtained comprising;

obtaining the last pressure sample in the plurality of pressure patterns;

obtaining the first from last pressure sample in the plurality of pressure samples;

obtaining the second from last pressure sample in the plurality of pressure samples;

obtaining the third from last pressure sample in the plurality of pressure samples;

determining whether the third from the last pressure sample is greater than the sum of the second from the last pressure sample and the product of 1.5 multiplied by the level of background noise;

determining whether the last pressure sample is greater than the sum of the first from the last pressure sample and the product of 1.5 multiplied by the level of background noise; and

when it is determined that the third from the last pressure sample is greater than the sum of the second from the last pressure sample and the product of 1.5 multiplied by the level of background noise and when it is determined that the last pressure sample is greater than the sum of the first from last pressure sample and the product of 1.5 multiplied by the level of background noise, make a determination that a cuff slippage condition exists.

20. The computer-readable storage medium of claim 19, further comprising:

make a determination that more than 10 cuff slippage conditions have occurred; and

when it is determined that more than 10 cuff slippage conditions have occurred, take a form of action, wherein take a form of action comprises initiating a cuff deflation cycle and setting an alert for a user to alert the user to the slippage condition.