Imonitha ye-blood-oxygen ibonisa iphesenti legazi elilayishwe umoya-mpilo.Ngokuqondile, ikala ukuthi yiliphi iphesenti le-hemoglobin, iphrotheni esegazini elithwala umoya-mpilo, elilayishiwe.Izigaba ezijwayelekile ezamukelekayo zeziguli ezingenazo izifo zamaphaphu zisuka kumaphesenti angama-95 kuye kwangama-99.Egunjini lokuphefumula lesiguli umoya osezingeni noma eduze kolwandle, isilinganiso se-arterial pO2ingenziwa ngemonitha ye-blood-oxygen "saturation of peripheral oxygen" (SpO2) ukufunda.
I-pulse oximeter evamile isebenzisa iphrosesa kagesi kanye nepheya lama-LED amancane e-light-emitting diode (ama-LED) abheke i-photodiode engxenyeni yomzimba wesiguli ekhanyayo, ngokuvamile iminwe yomunwe noma indlebe.I-LED eyodwa ibomvu, inobude begagasi obungu-660 nm, kanti enye ine-infrared enobude obungu-940 nm.Ukumuncwa kokukhanya kulawa maza wamaza kwehluka kakhulu phakathi kwegazi eligcwele umoya-mpilo kanye negazi elintula umoya-mpilo.I-hemoglobin ene-oxygen imunca ukukhanya okwengeziwe kwe-infrared futhi ivumele ukukhanya okubomvu okwengeziwe kudlule.I-Deoxygenated hemoglobin ivumela ukukhanya okwengeziwe kwe-infrared ukuthi kudlule futhi ibambe ukukhanya okubomvu okwengeziwe.Ama-LED alandelana ngomjikelezo wawo wokuvula okukodwa, bese omunye, bese ecisha womabili izikhathi ezingamashumi amathathu ngomzuzwana ovumela i-photodiode ukuthi iphendule ekukhanyeni okubomvu ne-infrared ngokuhlukana futhi ilungisele isisekelo sokukhanya okuzungezile.
Inani lokukhanya elidluliswayo (ngamanye amazwi, elingamuncwe) liyalinganiswa, futhi amasignali ahlukene ajwayelekile akhiqizwa ngobude begagasi ngalinye.Lezi zimpawu ziyashintshashintsha ngokuhamba kwesikhathi ngoba inani legazi le-arterial elikhona liyakhuphuka (ngokoqobo ishayela) ngokushaya kwenhliziyo ngakunye.Ngokukhipha ukukhanya okuncane okudlulisiwe ekukhanyeni okudlulisiwe kubude beza obunye, imiphumela yezinye izicubu iyalungiswa, ikhiqize isignali eqhubekayo ye-pulsatile arterial blood.Isilinganiso sesilinganiso sokukhanya okubomvu esilinganisweni sokukhanya kwe-infrared sibe sesibalwa iphrosesa. (okumelela isilinganiso se-hemoglobin ene-oxygen ne-deoxygenated hemoglobin), futhi lesi silinganiso siguqulelwa ku-SpO2ngephrosesa ngetafula lokubheka elisekelwe emthethweni we-Beer-Lambert.Ukuhlukaniswa kwesignali futhi kufeza ezinye izinjongo: i-plethysmograph waveform (“pleth wave”) emele isignali ye-pulsatile ngokuvamile iboniswa ukuze kube inkomba ebonakalayo yamapulses kanye nekhwalithi yesignali, kanye nenani lezinombolo phakathi kokudonsa kwe-pulsatile kanye nesisekelo (“perfusion index”) ingasetshenziselwa ukuhlola ukuxutshwa kwamanzi.
Isikhathi sokuthumela: Jul-01-2019