Optics: measuring and testing – Blood analysis – Hemoglobin concentration
Patent
1986-08-18
1989-08-22
Anderson, Bruce C.
Optics: measuring and testing
Blood analysis
Hemoglobin concentration
G01N 3348
Patent
active
048590568
ABSTRACT:
The disclosed invention is for use in extracting more accurate information from signals employed in pulse oximetry. Basically, pulse oximetry involves the illumination of arterial blood flowing in tissue with light at two wavelengths. Upon emerging from the tissue the light is received by a detector (38) that produces signals that are proportional to the intensity of the light received at each of the wavelengths. Each signal includes a slowly varying baseline component representing the attenuation .beta.(t) of light produced by bone, tissue, skin, and hair. The signals also include pulsatile components representing the attenuation .alpha.(t) produced by the changing blood volume and oxygen saturation within the finger. The signals produced by the detector (38) are converted by an analog-to-digital (A/D) converter (72) for subsequent analysis by a microcomputer (16). The microcomputer (16) extracts the following information from the signal corresponding to each wavelength. V.sub.H is determined to be the signal magnitude at a second pulse diastole. V.sub.L is, similarly, the signal magnitude at systole of the same pulse. A term .DELTA.V is identified equal in value to the difference in signal magnitudes at the adjacent systoles. Finally, values are determined for .DELTA.ts and .DELTA.tp, being the interval between an adjacent systole and diastole and the pulse period, respectively. The microcomputer (16) then determines a value for R.sub.OS in accordance with the relationship: ##EQU1## Empirically derived oxygen saturation curves are used to develop an indication of the oxygen saturation from the value of R.sub.OS computed.
REFERENCES:
patent: 2706927 (1955-04-01), Wood
patent: 3704706 (1972-12-01), Herczfeld et al.
patent: 3847483 (1974-11-01), Shaw et al.
patent: 3998550 (1976-12-01), Konishi et al.
patent: 4086915 (1978-05-01), Kofsky et al.
patent: 4114604 (1978-09-01), Shaw et al.
patent: 4167331 (1979-09-01), Nielsen
patent: 4266554 (1981-05-01), Hamaguri
patent: 4357105 (1982-11-01), Loretz
patent: 4407290 (1983-10-01), Wilber
patent: 4446871 (1984-05-01), Imura
patent: 4523279 (1985-06-01), Sperinde et al.
patent: 4621643 (1986-11-01), New et al.
Prosser Stephen J.
Smith Robert E.
Anderson Bruce C.
Physio-Control Corporation
LandOfFree
Multiple-pulse method and apparatus for use in oximetry does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multiple-pulse method and apparatus for use in oximetry, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multiple-pulse method and apparatus for use in oximetry will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2415121