US5746206A - Isolated Layer Pulse Oximetry - Google Patents

From MSc Voice Technology
Jump to navigation Jump to search


Another drawback is that the calculated oxygen saturation value is influenced by pulsatile sign contributions from many differing tissue layers, including the skin or floor tissue layer. U.S. Pat. No. 5,188,108 issued to Secker suggests the usage of a plurality of emitters and/or receivers to supply multiple emitter/receiver combination. Specifically, BloodVitals SPO2 the current invention permits for pulsed oximetry measurement which isolates arterial saturation ranges for particular ranges of tissue layers which rejects saturation ranges of the tissue above or below the tissue of curiosity by using a number of spaced detectors and/or emitters. FIG. Four is an total block diagram displaying the key components 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 principles of the invention for deep and BloodVitals SPO2 shallow tissue measurements, and values obtained without utilizing the ideas of the invention. FIG. 1A is a schematic diagram exhibiting the rules of operation of the present invention.



10 at subdermal tissue degree 12 having mild absorption properties u b . 14 Interposed between the non-invasive monitoring and measurement system (not proven) and subdermal tissue level 12, is pores and skin or floor blood oxygen monitor tissue level 14 having light absorption properties u a . It is deemed fascinating to measure arterial oxygen saturation within the tissue layer 12 or the tissue layer 14 independently. Sixteen transmits electromagnetic radiation within the visible and close to 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, totally different emitters may be used for BloodVitals SPO2 the completely different predetermined wavelengths, if desired. If a couple of emitter is used, it is most handy that they be co-situated to simulate a single point supply. LED's are a most popular type of emitter. Sixteen journey typically alongside path 18 to a first detector 20 and BloodVitals SPO2 alongside path 22 to a second detector 24 as shown.



18 within layer 12 (with absorption u b ) is shown as L 1 and the size of path 22 inside layer 12 is proven 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, BloodVitals SPO2 because paths 18 and 22 traverse skin layer 14 using roughly the identical angle, the first difference between paths 22 and 18 is the difference between size L 2 and size L 1 traversing subdermal layer 12, which is the tissue layer of curiosity. Therefore, it may be assumed that the difference in absorption between path L 2 and path L 1 is straight attributable to subdermal layer 12, the tissue layer of curiosity, corresponding to the completely 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 taken into account.



Equation 8 is equal to conventional pulse oximetry if the second detector BloodVitals SPO2 is eliminated. 16,20 (i.e. r 1 ) and the second emitter/detector pair 16,24 (i.e. r 2 ) should be bigger than several occasions the pores and BloodVitals SPO2 device skin thickness (i.e. r 1 ,r 2 much higher than d) in order that the 4 occurrences of are all approximately equal, or at the least have equivalent counterparts influencing the two detectors. If the detectors are too close to one another, BloodVitals SPO2 ⁇ FIG. 1B is a schematic diagram, just like FIG. 1A, exhibiting the present invention employing multiple emitters sixteen and 17 and a single detector BloodVitals SPO2 device 24. Those of skill within the artwork will admire that the operation is similar to that described above. FIG. 2 is a perspective view of the popular mode of affected person interface gadget 26 employing the present invention. Planar floor 28 is positioned into contact with the skin of the affected person during monitoring and measurement.



If desirable, BloodVitals SPO2 this position may be maintained through adhesive or different mechanical means known within the art. Further, if desirable, floor 28 could have a curvature, and could also be either versatile or rigid. 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 functions. FIG. Three is a partially sectioned view displaying affected person interface device 26 in operational position. Cable 32 conducts the electrical alerts to and from the monitoring circuitry as described below. All other parts are as beforehand described. FIG. Four is a block diagram exhibiting your entire monitoring and measurement system using the current invention. 36 and two wavelength driver 34 alternately activate the red and infrared LED's 16 at a desired chop frequency (e.g. 1,600 hz). CPU forty eight for calculating arterial oxygen saturation. PCT/US94/03546, the disclosure of which is integrated herein by reference. Alternate control electronics are recognized in the artwork and could possibly be used, if desired.