Systems and methods for non-invasive determination of blood pressure

• US 8,628,477 B2
• Filed: 07/31/2009
• Issued: 01/14/2014
• Est. Priority Date: 07/31/2009
• Status: Active Grant

• Current Assignee: Nellcor Puritan Bennett Ireland
• Original Assignee: Nellcor Puritan Bennett Ireland
• Inventors: Addison, Paul Stanley, Watson, James
• Primary Examiner(s): Mallari, Patricia
• Assistant Examiner(s): WESTON, TIFFANY C
• Application Number:
  US12/533,224
• Publication Number:
  US 20110028854A1
• Time in Patent Office: 1,628 Days
• Field of Search: 600490-499
• US Class Current: 600/493
• CPC Class Codes: A61B 5/02225 using the oscillometric method
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/726 using Wavelet transforms

Abstract

Methods and systems for determining blood pressure from a pressure signal are disclosed. A patient'"'"'s blood pressure may be determined by analyzing features of a wavelet transformation of a pressure signal obtained during an occlusion procedure. Ridges in a scalogram of the transformed signal may be identified and used to determine an envelope of a pressure oscillation signal, to which oscillometric blood pressure determination techniques may be applied.

Claims

1. A method for determining a blood pressure measurement, comprising:

receiving, from a sensor, an electronic signal responsive to an occluding device applied to a patient;

using processor equipment for;

transforming the electronic signal into a transformed signal based at least in part on a continuous wavelet transformation,

generating a scalogram based at least in part on the transformed signal, wherein the scalogram comprises 3-dimensional information,

identifying, within the scalogram, a ridge indicative of the patient'"'"'s blood flow as a function of time, and

determining a blood pressure measurement based at least in part on the identified ridge; and

outputting the blood pressure measurement to an output device.

2. The method of claim 1, further comprising applying a variable occluding pressure to a patient using the occluding device.

3. The method of claim 1, wherein the sensor is a pressure transducer associated with the occluding device.

4. The method of claim 1, wherein the blood pressure measurement comprises at least one of a systolic blood pressure, a diastolic blood pressure and a mean arterial pressure.

5. The method of claim 1, further comprising using processor equipment for determining an oscillation envelope based at least in part on the identified ridge, wherein determining a blood pressure measurement is based at least in part on the oscillation envelope.

6. The method of claim 5, wherein the oscillation envelope is based at least in part on a projection of the identified ridge.

7. The method of claim 1, wherein determining a blood pressure measurement is further based at least in part on a maximum amplitude of the identified ridge.

8. A system for determining a blood pressure measurement, comprising:

an occluding device capable of being applied to a patient;

a sensor, coupled to the occluding device, that outputs an electronic signal responsive to the occluding device when the occluding device is applied to the patient;

processor equipment, coupled to the sensor, the processor equipment being capable of;

transforming the electronic signal into a transformed signal based at least in part on a continuous wavelet transformation,

generating a scalogram based at least in part on the transformed signal, wherein the scalogram comprises 3-dimensional information,

identifying, within the scalogram, a ridge indicative of the patient'"'"'s blood flow as a function of time,

determining a blood pressure measurement based at least in part on the identified ridge; and

an output device, coupled to the processor equipment, for outputting the blood pressure measurement.

9. The system of claim 8, wherein the occluding device is capable of applying a variable occluding pressure to a patient.

10. The system of claim 8, wherein the sensor is a pressure transducer associated with the occluding device.

11. The system of claim 8, wherein the blood pressure measurement comprises at least one of a systolic blood pressure, a diastolic blood pressure and a mean arterial pressure.

12. The system of claim 8, wherein the processor equipment is further capable of determining an oscillation envelope based at least in part on the identified ridge, wherein determining a blood pressure measurement is based at least in part on the oscillation envelope.

13. The system of claim 12, wherein the oscillation envelope is based at least in part on a projection of the identified ridge.

14. The system of claim 8, wherein determining a blood pressure measurement is further based at least in part on a maximum amplitude of the identified ridge.

15. Non-transitory computer-readable medium for use in determining a blood pressure measurement, the computer-readable medium having computer program instructions recorded thereon for:

receiving, from a sensor, an electronic signal responsive to an occluding device applied to a patient,

transforming the electronic signal into a transformed signal based at least in part on a continuous wavelet transformation,

generating a scalogram based at least in part on the transformed signal, wherein the scalogram comprises 3-dimensional information,

identifying, within the scalogram, a ridge indicative of the patient'"'"'s blood flow as a function of time,

determining a blood pressure measurement based at least in part on the identified ridge, and

outputting the blood pressure measurement to an output device.

16. The non-transitory computer-readable medium of claim 15, further having computer program instructions recorded thereon for directing the occluding device to apply a variable occluding pressure to a patient.

17. The non-transitory computer-readable medium of claim 15, wherein the sensor is a pressure transducer associated with the occluding device.

18. The non-transitory computer-readable medium of claim 15, wherein the blood pressure measurement comprises at least one of a systolic blood pressure, a diastolic blood pressure and a mean arterial pressure.

19. The non-transitory computer-readable medium of claim 15, further having computer program instructions recorded thereon for determining an oscillation envelope based at least in part on the identified ridge, wherein determining a blood pressure measurement is based at least in part on the oscillation envelope.

20. The non-transitory computer-readable medium of claim 19, wherein the oscillation envelope is based at least in part on a projection of the identified ridge.