Method and Device for Determining the Perfusion of Blood in a Body Member

• US 20080188728A1
• Filed: 03/06/2006
• Published: 08/07/2008
• Est. Priority Date: 03/14/2005
• Status: Abandoned Application

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Neumann, Rolf, Noller, Friedemann
• Application Number:
  US11/908,133
• Publication Number:
  US 20080188728A1
• Time in Patent Office: Days
• US Class Current: 600/336
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips

Abstract

The invention relates to a method and device for determining the perfusion of blood in a body member. Furthermore, the invention relates to a computer program for determining the perfusion of blood in a body member. To provide a technique to ensure that the actual patient perfusion condition does correlate with the calculated perfusion index value over a broad variety of patient conditions, a new method of determining the perfusion of blood in a body member is suggested, the method comprising the steps of: producing electrical measuring signals from a non-invasive photometric measuring process, normalizing the electrical measuring signals and determining a perfusion index from the normalized signals, using an energy value of at least one signal pulse.

Claims

1. A method of determining the perfusion of blood in a body member (5), the method comprising the steps of producing electrical measuring signals from a non-invasive photometric measuring process, normalizing the electrical measuring signals and determining a perfusion index (Perf) from the normalized signals, using an energy value (A) of at least one signal pulse.

2. The method as claimed in claim 1, wherein normalizing the electrical measuring signals comprises normalizing the electrical measuring signals with respect to the direct current level of the electrical measuring signals.

3. The method as claimed in claim 1, wherein the signal curve from the end of the diastole of a heart beat to the end of the diastole of the next heart beat is used for determining the energy value (A).

4. The method as claimed in claim 1, wherein the signal curve is analysed and only a part of the pulse is used for determining the energy value (A).

5. The method as claimed in claim 1, wherein the area of the pulse is estimated using a number of predefined geometric figures in order to determine an energy value (A).

6. The method as claimed in claim 1, wherein the impact of the blood saturation on the signals for wavelengths other than the isobestic wavelength is compensated for.

7. The method as claimed in claim 1, wherein the signals from the sensor are pre-filtered and/or artifact-reduced before the perfusion is determined.

8. A device (20) for determining the perfusion of blood in a body member (5), comprising a signal component (21) adapted for producing electrical measuring signals from a non-invasive photometric measuring process, and a determining component (22) adapted for normalizing the electrical measuring signals and for determining a perfusion index (Perf) from the normalized signals, using an energy value (A) of at least one signal pulse.

9. The device (20) as claimed in claim 8, wherein the signal component (21) is adapted for producing electrical measuring signals from a non-invasive photometric measuring process for determining the arterial oxygen saturation of the blood, the device (20) further comprising filter means (24) for reducing or eliminating the effect of signal artefacts, and wherein the determining component (22) is adapted for determining the perfusion index (Perf) from the pre-filtered and artifact-reduced signals.

10. A computer program (23) for determining the perfusion of blood in a body member (5), comprising computer program instructions to determine a perfusion index (Perf) from normalized electrical measuring signals from a non-invasive photometric measuring process, using an energy value (A) of at least one signal pulse, when the computer program (23) is executed in a computer (22).