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Uyini umsebenzi kanye nemisebenzi ye-finger pulse oximeter?

I-Fingertip pulse oximeter yasungulwa nguMillikan ngeminyaka yawo-1940s ukuqapha ukugcwala komoyampilo egazini le-arterial, inkomba ebalulekile yobukhali be-COVID-19.Yonker manje ichaza ukuthi i-finger pulse oximeter isebenza kanjani?

Izici zokumuncwa kwe-Spectral zezicubu zebhayoloji: Uma ukukhanya kushiswa kusicubu sebhayoloji, umthelela wezicubu zebhayoloji ekukhanyeni ungahlukaniswa ngezigaba ezine, okuhlanganisa ukumuncwa, ukuhlakazeka, ukuboniswa kanye ne-fluorescence.Uma ukuhlakazeka kukhishiwe, ibanga elihanjwa ukukhanya kubhayoloji. izicubu ikakhulukazi zilawulwa ukumuncwa.Lapho ukukhanya kungena kwezinye izinto ezibonisa ngale (okuqinile, okuwuketshezi noma okunegesi), amandla okukhanya ancipha kakhulu ngenxa yokumuncwa okuhlosiwe kwezingxenye ezithile zefrikhwensi, okuwukumuncwa kokukhanya ngezinto.Ukuthatha ukukhanya okungakanani kubizwa ngokuthi i-optical density, eyaziwa nangokuthi ukumunca.

Umdwebo weschematic wokumuncwa kokukhanya ngendaba kuyo yonke inqubo yokusakazwa kokukhanya, inani lamandla okukhanya amuncwa udaba lilingana nezinto ezintathu, okungamandla okukhanya, ibanga lendlela yokukhanya kanye nenani lezinhlayiya ezimunca ukukhanya ingxenye yesiphambano sendlela yokukhanya.Ngokwesisekelo sezinto ezilinganayo, izinhlayiya ezimunca ukukhanya zendlela yokukhanya esigabeni esiphambanayo zingathathwa njengezinhlayiya ezimunca ukukhanya ngeyunithi ngayinye, okungukuthi ukugxilwa kwezinhlayiyana zokukhanya okumunca impahla, zingathola umthetho kabhiya we-lambert: kungahunyushwa njengokugxiliswa kwempahla kanye ubude bendlela yokubona ngeyunithi ngayinye yevolumu ye-optical density, amandla okukhanya okumunca okubalulekile okuphendula imvelo yokukhanya okudonsayo. Ngamanye amazwi, umumo wejika le-spectrum yokumuncwa wento efanayo uyafana, kanye nesimo esiphelele ukuphakama kokumuncwa kuzoshintsha kuphela ngenxa yokugxila okuhlukile, kodwa indawo ehlobene izohlala ingashintshile.Enqubweni yokumuncwa, ukumuncwa kwezinto zonke kwenzeka ngevolumu yesigaba esifanayo, futhi izinto ezimuncayo azihlobene, futhi azikho izinhlanganisela ze-fluorescent ezikhona, futhi akukho mkhuba wokushintsha izakhiwo ze-medium ngenxa imisebe yokukhanya.Ngakho-ke, ngesixazululo esinezingxenye zokumuncwa kwe-N, ukuminyana kwe-optical kuyisengezo.Ukungezwa kokuminyana kokubona kunikeza isisekelo sethiyori sokulinganisa ubuningi bezingxenye zokumunca kuzingxube.

Ku-optics yezicubu zebhayoloji, isifunda se-spectral esingu-600 ~ 1300nm sivame ukubizwa ngokuthi "ifasitela le-biological spectroscopy", futhi ukukhanya kuleli bhande kunokubaluleka okukhethekile kokwelashwa okuningi okungaziwa nokungaziwa kanye nokuxilongwa kwe-spectral.Esifundeni se-infrared, amanzi aba into ehamba phambili emunca ukukhanya ezicutshini zebhayoloji, ngakho ubude begagasi obumukelwe uhlelo kufanele bugweme ukumuncwa kwamanzi ukuze kutholwe kangcono ulwazi lokumunca ukukhanya lwento eqondiwe.Ngakho-ke, phakathi kwe-spectrum eseduze-infrared spectrum engu-600-950nm, izingxenye eziyinhloko zethishu yethiphu yomunwe womuntu enamandla okumunca ukukhanya zifaka amanzi egazini, i-O2Hb(i-hemoglobin ene-oxygenated), i-RHb(i-hemoglobin encishisiwe) kanye ne-peripheral skin melanin nezinye izicubu.

Ngakho-ke, singathola ulwazi olusebenzayo lokugxila kwengxenye okumele ilinganiswe esicutshini ngokuhlaziya idatha ye-spectrum ephumayo.Ngakho-ke uma sinokugxilisa kwe-O2Hb ne-RHb, siyakwazi ukugcwala komoyampilo.I-Oxygen saturation SpO2ingabe iphesenti lomthamo we-hemoglobin (HbO2) eboshelwe komoya-mpilo egazini njengephesenti lengqikithi ye-hemoglobin ebophayo (Hb), ukugcwala kokushaya kwenhliziyo komoya-mpilo ngakho kungani ibizwa ngokuthi i-pulse oximeter?Nawu umqondo omusha: ukugeleza kwegazi umthamo we-pulse wave.Phakathi nomjikelezo ngamunye wenhliziyo, ukufinyela kwenhliziyo kubangela umfutho wegazi ukhuphuke emithanjeni yegazi yempande ye-aorta, enweba udonga lwemithambo yegazi.Ngakolunye uhlangothi, i-diastole yenhliziyo ibangela ukuba umfutho wegazi wehle emithanjeni yegazi yempande ye-aorta, okubangela ukuba udonga lwemithambo yegazi lufinyele.Ngokuphindaphinda okuqhubekayo komjikelezo wenhliziyo, ushintsho oluqhubekayo lomfutho wegazi emithanjeni yegazi yempande ye-aorta izodluliselwa emithanjeni engezansi exhunywe nayo ngisho nakulo lonke uhlelo lwe-arterial, ngaleyo ndlela kwakha ukwanda okuqhubekayo nokufinyela kwe-aorta. lonke udonga lwemithambo yegazi.Okusho ukuthi, ukushaya kwenhliziyo ngezikhathi ezithile kudala amagagasi okushaya kwenhliziyo ku-aorta agelezela phambili eduze kwezindonga zemithambo yegazi kulo lonke uhlelo lwe-arterial.Ngaso sonke isikhathi lapho inhliziyo ikhula futhi ifinyela, ukuguqulwa kwengcindezi ohlelweni lwe-arterial kukhiqiza igagasi lokushaya kwenhliziyo ngezikhathi ezithile.Yilokhu esikubiza ngokuthi i-pulse wave.I-Pulse wave ingabonisa ulwazi oluningi lwezemvelo njengenhliziyo, umfutho wegazi nokugeleza kwegazi, okunganikeza ulwazi olubalulekile lokutholwa okungahlanyisi kwamapharamitha athile omzimba womuntu.

SPO2
Pulse Oximeter

Kwezokwelapha, i-pulse wave ivame ukuhlukaniswa ibe yi-pressure pulse wave kanye ne-volume pulse wave izinhlobo ezimbili.I-Pressure pulse wave imele ngokuyinhloko ukudluliswa komfutho wegazi, kuyilapho i-volume pulse wave imelela izinguquko ngezikhathi ezithile ekugelezeni kwegazi.Uma kuqhathaniswa ne-pressure pulse wave, i-volumetric pulse wave iqukethe ulwazi olubaluleke kakhulu lwenhliziyo nemithambo yegazi njengemithambo yegazi yomuntu nokugeleza kwegazi.Ukutholwa okungavamisile kokugeleza kwegazi okujwayelekile kwevolumu ye-pulse wave kungafinyelelwa nge-photoelectric volumetric pulse wave tracing.Igagasi elithile lokukhanya lisetshenziselwa ukukhanyisa ingxenye yokulinganisa yomzimba, futhi umsebe ufinyelela inzwa ye-photoelectric ngemva kokuboniswa noma ukudluliswa.I-beam etholiwe izophatha ulwazi olusebenzayo lwesici se-volumetric pulse wave.Ngenxa yokuthi umthamo wegazi uyashintsha ngezikhathi ezithile ngokunwetshwa nokufinyela kwenhliziyo, lapho inhliziyo ye-diastole, ivolumu yegazi incane kakhulu, ukumuncwa kwegazi kokukhanya, inzwa ithole ubukhulu bokukhanya okukhulu;Lapho inhliziyo ifinyela, ivolumu iphezulu futhi ukukhanya okutholwe inzwa kuncane.Ekubonweni okungahlanyisi kweminwe nge-blood flow volume pulse wave njengedatha yokulinganisa eqondile, ukukhethwa kwesayithi lokulinganisa i-spectral kufanele kulandele izimiso ezilandelayo.

1. Imithambo yegazi kufanele ibe kuningi kakhulu, futhi ingxenye yolwazi olusebenzayo olufana ne-hemoglobin ne-ICG enanini lengqikithi yolwazi ku-spectrum kufanele ithuthukiswe.

2. Inezici ezisobala zokushintshwa kwevolumu yokugeleza kwegazi ukuze iqoqe ngokuphumelelayo isignali ye-volume pulse wave

3. Ukuze uthole i-spectrum yomuntu ngokuphindaphinda okuhle nokuzinza, izici zezicubu azithinteki kancane ngokuhlukana komuntu ngamunye.

4. Kulula ukwenza ukubonwa kwe-spectral, futhi kulula ukwamukelwa yisihloko, ukuze ugweme izici zokuphazamiseka ezifana nokushaya kwenhliziyo okusheshayo nokunyakaza kokuma kokulinganisa okubangelwa imizwa yokucindezeleka.

Umdwebo wohlelo lokusatshalaliswa kwemithambo yegazi entendeni yesandla somuntu Indawo yengalo ayikwazi ukubona igagasi lokushaya kwenhliziyo, ngakho-ke ayifanele ukutholwa kokugeleza kwegazi kwevolumu ye-pulse wave;Isihlakala siseduze nomthambo we-radial, isignali ye-pressure pulse wave inamandla, isikhumba kulula ukukhiqiza ukudlidliza komshini, kungase kuholele esignali yokuthola ngaphezu kwe-volume pulse wave futhi iphathe ulwazi lwe-pulse reflection yesikhumba, kunzima ukunemba ngokunembile. bonakalisa izici zokuguqulwa kwevolumu yegazi, ayifanele isikhundla sokulinganisa;Nakuba intende yesandla ingenye yezindawo ezivamile zokudweba igazi emitholampilo, ithambo layo lijiyile kunomunwe, futhi i-pulse wave wave yevolumu yesundu eqoqwe ngokubonakala okusabalalisa iphansi.Umfanekiso 2-5 ubonisa ukusatshalaliswa kwemithambo yegazi entendeni yesandla.Ukubuka lesi sibalo, kungabonakala ukuthi kunamanethiwekhi amaningi e-capillary engxenyeni engaphambili yomunwe, engabonisa ngokuphumelelayo okuqukethwe kwe-hemoglobin emzimbeni womuntu.Ngaphezu kwalokho, lesi sikhundla sinezici ezisobala zokushintshwa kwevolumu yokugeleza kwegazi, futhi indawo efanelekile yokulinganisa ye-volume pulse wave.Izicubu zemisipha nethambo zeminwe zincane, ngakho umthelela wolwazi lokuphazamiseka kwangemuva mancane uma kuqhathaniswa.Ngaphezu kwalokho, ichopho lomunwe kulula ukulilinganisa, futhi isihloko asinawo umthwalo ongokwengqondo, okulungele ukuthola isignali ye-spectral esezingeni eliphezulu yesignali-to-noise.Umunwe womuntu uqukethe ithambo, uzipho, isikhumba, izicubu, igazi le-venous kanye ne-arterial blood.Enqubweni yokusebenzelana nokukhanya, umthamo wegazi emithanjeni ye-peripheral yomunwe uyashintsha ngokushaya kwenhliziyo, okuholela ekushintsheni kokulinganisa indlela yokubona.Ngenkathi ezinye izingxenye zihlala njalo kuyo yonke inqubo yokukhanya.

Uma i-wavelength ethile yokukhanya isetshenziswa ku-epidermis yomunwe, umunwe ungathathwa njengengxube, okuhlanganisa izingxenye ezimbili: i-static matter (i-optical path is constant) kanye ne-dynamic matter (indlela yokubona ishintsha ngevolumu impahla).Lapho ukukhanya kudonswa izicubu zeminwe, ukukhanya okudlulisiwe kwamukelwa i-photodetector.Ukuqina kokukhanya okudlulisiwe okuqoqwe inzwa ngokusobala kuncishisiwe ngenxa yokumuncwa kwezingxenye zezicubu ezihlukahlukene zeminwe yomuntu.Ngokwalesi sici, imodeli elinganayo yokumunca ukukhanya kweminwe iyasungulwa.

Umuntu ofanelekayo:
Umunwe we-pulse oximeterifaneleka kubantu bayo yonke iminyaka, kuhlanganise nezingane, abantu abadala, asebekhulile, iziguli ezinesifo senhliziyo, umfutho wegazi ophakeme, i-hyperlipidemia, i-cerebral thrombosis nezinye izifo ze-vascular kanye neziguli ezine-asthma, i-bronchitis, i-bronchitis engapheli, isifo senhliziyo yamaphaphu nezinye izifo zokuphefumula.


Isikhathi sokuthumela: Jun-17-2022