Pulse oximeter

• US 4,883,353 A
• Filed: 02/11/1988
• Issued: 11/28/1989
• Est. Priority Date: 02/11/1988
• Status: Expired due to Fees

• Current Assignee: Puritan Bennett Corp. (Medtronic Plc)
• Original Assignee: Puritan Bennett Corp. (Medtronic Plc)
• Inventors: Hausman, Kenneth A., Merrick, Edwin B.
• Primary Examiner(s): McGraw, Vincent P.
• Application Number:
  US07/154,929
• Time in Patent Office: 656 Days
• Field of Search: 356/39, 356/40, 356/41, 128/633
• US Class Current: 356/41
• CPC Class Codes: A61B 5/02433 for infrared radiation
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor

Abstract

A pulse oximeter having a sensor responsive to light transmitted through an area of blood flow which is optically absorbed by hemoglobin for producing a pulsatile waveform indicating the current pulsatile component of blood flow. A process waveform is created for tracking the process of the oximeter during its determination of a maximum and a minimum value of the pulsatile waveform, which is used for calculating the saturation of oxygen.

Claims

1. oxygenated blood, onto an output display. 17. The method in accordance with claim 16 further comprising the step of determining a maximum and a

2. minimum value of said pulsatile waveform. 18. The method in accordance with claim 16 wherein said displayable process waveform comprises:

an upper envelope for tracking the process of determining said maximum value of the pulsatile waveform; and

a lower envelope for tracking the process of determining said minimum value

3. of the pulsatile waveform. 19. The method in accordance with claim 18 further comprising the step of uniquely coloring said upper envelope and

4. said lower envelope of the displayable process waveform. 20. The method in accordance with claim 16 further comprising the step of determining a predetermined percentage of said amplitude of said pulsatile waveform.

5. The method in accordance with claim 20 further comprising the steps of identifying a maximum value of said pulsatile waveform and recovering a pulsatile waveform value at a predetermined time period prior to said maximum value for determining said predetermined percentage of said

6. amplitude. 22. The method in accordance with claim 16 further comprising the step of correcting any amplitude errors of said pulsatile waveform that are caused by a wandering baseline.