Systems and Methods for Non-Invasive Continuous Blood Pressure Determination

• US 20090326393A1
• Filed: 09/30/2008
• Published: 12/31/2009
• Est. Priority Date: 06/30/2008
• Status: Active Grant

• Current Assignee: Nellcor Puritan Bennett Ireland
• Original Assignee: Nellcor Puritan Bennett Ireland
• Inventors: Watson, James, Sethi, Rakesh
• Granted Patent: US 8,398,556 B2
• Time in Patent Office: Days
• US Class Current: 600/494
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02108 from analysis of pulse wave characteristics
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: G06F 2218/10 by analysing the shape of a waveform, e.g. extracting parameters relating to peaks

Abstract

According to some embodiments, systems and methods are provided for non-invasive continuous blood pressure determination. In some embodiments, a PPG signal is received and locations of pulses within the PPG signal are identified. An area within a particular pulse is measured. The area may be of just the upstroke, downstroke or the entire pulse. The area may be measured relative to a time-domain axis or a baseline of the pulse. The pulse may be split into multiple sections and the area of each section may be measured. The area of one portion of the pulse may correspond to systolic blood pressure while the area of another portion may correspond to diastolic blood pressure. Empirical data may be used to determine blood pressure from the measured area by applying calibration data measured by a suitable device.

Claims

1. A method for determining blood pressure based on a PPG signal, the method comprising:

receiving locations of pulses in the PPG signal;

measuring an area under a portion of one of the pulses; and

determining blood pressure based on the measured area.

2. The method of claim 1 wherein the measured area is an area under the pulse from a starting point of the pulse to an ending point of the pulse relative to a baseline of the pulse.

3. The method of claim 1 wherein the measured area is an area under the pulse from a starting point of the pulse to an ending point of the pulse relative to a temporal axis.

4. The method of claim 1 wherein the measured area is an area under an upstroke portion of the pulse relative to a baseline of the pulse.

5. The method of claim 1 wherein the measured area is an area under an upstroke portion of the pulse relative to a temporal axis.

6. The method of claim 1 wherein measuring an area under the pulse further comprises:

splitting the pulse along the temporal axis;

measuring a first area corresponding to a first portion of the split pulse;

measuring a second area corresponding to a second portion of the split pulse; and

determining the blood pressure based on one of the measured areas.

7. The method of claim 1 wherein determining blood pressure based on the measured area comprises correlating the measured area with empirical data.

8. The method of claim 7 wherein the empirical data relates to a patient or at least one other patient.

9. The method of claim 7 wherein correlating the measured area with empirical data comprises applying a linear or non-linear approximation equation of empirical data to the measured area.

10. The method of claim 9 wherein the linear or non-linear approximation equation is derived by applying calibration data.

11. The method of claim 1 wherein the blood pressure is determined by applying a function to the measured area to compute the blood pressure or looking up a corresponding blood pressure value associated with the measured area in a table.

12. A system for determining blood pressure based on a PPG signal, the system comprising:

processing circuitry capable of;

receiving locations of pulses in the PPG signal;

measuring an area under a portion of one of the pulses; and

determining blood pressure based on the measured area.

13. The system of claim 12 wherein the measured area is an area under the pulse from a starting point of the pulse to an ending point of the pulse relative to a baseline of the pulse.

14. The system of claim 12 wherein the measured area is an area under the pulse from a starting point of the pulse to an ending point of the pulse relative to a temporal axis.

15. The system of claim 12 wherein the measured area is an area under an upstroke portion of the pulse relative to a baseline of the pulse.

16. The system of claim 12 wherein the measured area is an area under an upstroke portion of the pulse relative to a temporal axis.

17. The system of claim 12 wherein the processing circuitry is further capable of:

splitting the pulse along the temporal axis;

measuring a first area corresponding to a first portion of the split pulse;

measuring a second area corresponding to a second portion of the split pulse; and

determining the blood pressure based on L one of the measured areas.

18. The system of claim 12 wherein the processing circuitry is further capable of correlating the measured area with empirical data.

19. The system of claim 18 wherein the empirical data relates to a patient or at least one other patient.

20. The system of claim 18 wherein the processing circuitry is further capable of applying a linear or non-linear approximation equation of empirical data to the measured area.

21. The system of claim 20 wherein the linear or non-linear approximation equation is derived by applying calibration data.

22. The system of claim 12 wherein the blood pressure is determined by applying a function to the measured area to compute the blood pressure or looking up a corresponding blood pressure value associated with the measured area in a table.

23. Computer-readable medium for use in determining blood pressure based on a PPG signal, the computer-readable medium having computer program instructions recorded thereon for:

for receiving locations of pulses in the PPG signal;

measuring an area under a portion of one of the pulses; and

determining blood pressure based on the measured area.