US5746206A - Isolated Layer Pulse Oximetry - Google Patents > 자유게시판

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Another drawback is that the calculated oxygen saturation value is influenced by pulsatile sign contributions from many differing tissue layers, including the pores and skin or floor tissue layer. U.S. Pat. No. 5,188,108 issued to Secker suggests the use of a plurality of emitters and/or receivers to provide multiple emitter/receiver combination. Specifically, the current invention allows for pulsed oximetry measurement which isolates arterial saturation ranges for particular ranges of tissue layers which rejects saturation ranges of the tissue above or beneath the tissue of curiosity by utilizing a number of spaced detectors and/or emitters. FIG. Four is an general block diagram showing the major parts of an operational system using the present invention. FIG. 6 is a graph of absorptivity vs. FIG. 7 is a graph comprising calculated oxygen saturation values utilizing the rules of the invention for deep and shallow tissue measurements, and values obtained with out using the ideas of the invention. FIG. 1A is a schematic diagram exhibiting the ideas of operation of the current invention.

10 at subdermal tissue level 12 having gentle absorption properties u b . 14 Interposed between the non-invasive monitoring and measurement system (not proven) and subdermal tissue level 12, is skin or surface tissue stage 14 having mild absorption properties u a . It's deemed fascinating to measure arterial oxygen saturation in the tissue layer 12 or the tissue layer 14 independently. Sixteen transmits electromagnetic radiation in the seen and BloodVitals home monitor near infrared area at two predetermined wavelengths (e.g. 660 nm and 905 nm). Emitter sixteen is proven as a single entity in this instance. However, completely different emitters may be used for the totally different predetermined wavelengths, if desired. If multiple emitter is used, it is most handy that they be co-situated to simulate a single level supply. LED's are a most popular sort of emitter. 16 journey typically along path 18 to a first detector 20 and alongside path 22 to a second detector 24 as proven.

18 inside layer 12 (with absorption u b ) is shown as L 1 and the size of path 22 within layer 12 is shown as L 2 . Detector 20 is spaced a distance of r 1 from emitter 16 and detector 24 is spaced at a distance of r 2 . 18 and path 22 traverse pores and skin layer 14 twice. Furthermore, as a result of paths 18 and 22 traverse pores and skin layer 14 using approximately the identical angle, the primary difference between paths 22 and 18 is the difference between size L 2 and length L 1 traversing subdermal layer 12, which is the tissue layer of curiosity. Therefore, it may be assumed that the distinction in absorption between path L 2 and path L 1 is immediately attributable to subdermal layer 12, the tissue layer of interest, corresponding to the totally different spacings r 2 and r 1 . 12 may be represented by l and the deeper path through the subdermal tissue by L 1 and L 2 , relying on which detector is considered.

Equation 8 is equivalent to typical pulse oximetry if the second detector Blood Vitals is eradicated. 16,20 (i.e. r 1 ) and the second emitter/detector pair 16,24 (i.e. r 2 ) needs to be larger than several occasions the skin thickness (i.e. r 1 ,r 2 much better than d) in order that the four occurrences of are all roughly equal, or a minimum of have equivalent counterparts influencing the two detectors. If the detectors are too close to one another, ⁇ FIG. 1B is a schematic diagram, similar to FIG. 1A, BloodVitals home monitor showing the current invention employing a number of emitters sixteen and 17 and a single detector 24. Those of ability within the art will respect that the operation is much like that described above. FIG. 2 is a perspective view of the preferred mode of patient interface device 26 using the current invention. Planar surface 28 is positioned into contact with the skin of the patient during monitoring and measurement.

If fascinating, this position may be maintained via adhesive or different mechanical means recognized in the art. Further, if fascinating, surface 28 might have a curvature, and may be either versatile or inflexible. 16, detector 20, and detector 24 are as beforehand mentioned. Wiring electrically couples emitter 16, detector 20, and detector 24 to the circuitry which performs the monitoring features. FIG. Three is a partially sectioned view exhibiting patient interface device 26 in operational position. Cable 32 conducts the electrical indicators to and from the monitoring circuitry as described under. All different components are as previously described. FIG. 4 is a block diagram exhibiting the entire monitoring and BloodVitals home monitor measurement system employing the present invention. 36 and two wavelength driver 34 alternately activate the red and infrared LED's sixteen at a desired chop frequency (e.g. 1,600 hz). CPU forty eight for BloodVitals wearable calculating arterial oxygen saturation. PCT/US94/03546, the disclosure of which is included herein by reference. Alternate management electronics are identified in the artwork and could be used, if desired.