Method for digitally processing signals containing information regarding arterial blood flow

• US 5,349,519 A
• Filed: 11/12/1993
• Issued: 09/20/1994
• Est. Priority Date: 09/15/1989
• Status: Expired due to Term

• Current Assignee: Philips Electronics North America Corporation (Koninklijke Philips N.V.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Kaestle, Siegfried
• Primary Examiner(s): Hayes, Gail O.
• Application Number:
  US08/151,321
• Time in Patent Office: 312 Days
• Field of Search: 364/413.09, 128/633, 128/695
• US Class Current: 600/500
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives

Abstract

A method for digitally processing signals containing information regarding arterial blood flow in a living body is disclosed enabling a more accurate determination of the oxygen saturation. The method comprises the steps of identifying a first edge based on a first derivation of the signal, disregarding same if it does not fulfill certain criteria, determining a window based on said identified first edge, identifying the second edge falling within said window, disregarding same if it does not fulfill certain criteria, and replacing the second edge by the first before repeated these steps.

Claims

1. A method for identifying acceptable systolic edges in a blood pressure signal derived from a patient comprising:

identifying as a first systolic edge a portion of the signal meeting criteria for at least one feature including the maximum absoluted value of a first derivative;

determining value windows for respective features including those with wide variations only from the values of the features in said first systolic edge; and

determining whether a subsequent portion of said signal passes through said value windows; and

identifying it as being an acceptable edge if it does.

2. A method for identifying acceptable systolic edges in a blood pressure signal derived from a patent comprising:

identifying as a first systolic edge a portion of the signal meeting criteria for at least one feature including the maximum absolute value of a first derivative;

determining value windows for the respective features including those with wide variations from their values int he first systolic edge and excluding their values in previous systolic edges; and

determining whether a subsequent portion of said signal passes through said value windows; and

identifying it as being an acceptable edge if it does.

3. A method for identifying acceptable systolic edges in a blood pressure signal derived from a patient comprising:

identifying as a first systolic edge a portion of the signal meeting criteria for at least one features;

determining value windows for respective features including those with wide variation only from the values of the features in said first systolic edge; and

determining whether a subsequent portion of said signal passes through said value windows; and

identifying it as being an acceptable edge if it does.

4. A method for identifying acceptable systolic edges in a blood pressure signal derived from a patient comprising:

identifying as a first systolic edge a portion of the signal meeting criteria for at least one feature including the maximum absolute value of a first derivative;

determining value windows for respective features including those with wide variations from the values of the features in said first systolic edge but not from values in previous systolic edges.