I-Fingertip pulse oximeter yaqanjwa nguMillikan ngeminyaka yee-1940s ukujonga ukuxinana kweoksijini kwi-arterial blood, isalathisi esibalulekileyo sobungqongqo be-COVID-19.Yonker ngoku ichaza ukuba i-fingertip pulse oximeter isebenza njani?
Iimpawu ze-Spectral zokufunxa izicubu zebhayoloji: Xa ukukhanya kukhanya kwi-tissue ye-biological, umphumo we-biological tissue ekukhanyeni unokwahlulahlula kwiindidi ezine, kubandakanywa ukufunxa, ukusabalalisa, ukubonakalisa kunye ne-fluorescence. Xa ukukhanya kugqobhoza izinto ezicacileyo (eziqinileyo, ezilulwelo okanye ezinerhasi), ubunzulu bokukhanya buyancipha ngokubonakalayo ngenxa yokufunxwa okujoliswe kuko kwamacandelo athile amaza athile, nto leyo iyinto yokufunxa ukukhanya zizinto. Ubungakanani bekhaphukhaphu efunxayo kubizwa ngokuba yi-optical density, okwakwaziwa ngokuba yi-absorption.
Umzobo weSchematic of absorption wokukhanya ngumcimbi kuyo yonke inkqubo yokusasazwa kokukhanya, ubungakanani bamandla okukhanya afunnwe ngumcimbi bulingana nezinto ezintathu, ezibukukhanya kokukhanya, umgama wendlela yokukhanya kunye nenani lamasuntswana afunxa ukukhanya kumnqamlezo wendlela yokukhanya. Kwisiseko sezinto ezilinganayo, inombolo yokukhanya kwendlela yokukhanya ethatha ukukhanya kwinqanaba elinqamlezileyo linokuthathwa njengamasuntswana athatha ukukhanya kwiyunithi nganye, oko kukuthi, ukufunxa ukukhanya kwesuntswana lokuxinana, kunokufumana umthetho we-lambert yebhiya: inokutolikwa njengokugxilwa kwezinto kunye nobude bendlela yokukhanya kwiyunithi nganye yoxinaniso lwe-optical, ukufunxa indalo yokukhanya ukukwazi ukuphendula kwimo yokukhanya kokukhanya. Ijika le-spectrum yokufunxa yento enye iyafana, kwaye indawo epheleleyo yencopho yokufunxa iya kutshintsha kuphela ngenxa yoxinaniso olwahlukileyo, kodwa indawo ehambelanayo iya kuhlala ingatshintshi. Kwinkqubo yokufunxa, ukuxutywa kwezinto zonke kwenzeka kumthamo wecandelo elifanayo, kwaye izinto ezifunxayo azihambelani, kwaye akukho zixhobo ze-fluorescent zikhoyo, kwaye akukho nto yokutshintsha iimpawu ze-medium ngenxa yemitha yokukhanya. Ngoko ke, kwisisombululo esinamacandelo e-N yokufunxa, ubuninzi be-optical is additive. I-additivity ye-optical density inika isiseko sethiyori kumlinganiselo wobungakanani bezinto ezifunxayo kwimixube.
Kwi-biological tissue optics, ummandla we-spectral we-600 ~ 1300nm udla ngokubizwa ngokuba "yifestile ye-biological spectroscopy", kwaye ukukhanya kweli bhanti kunokubaluleka okukhethekileyo kunyango oluninzi olwaziwayo nolungaziwa kunye nokuxilongwa kwe-spectral. Kummandla we-infrared, amanzi aba yeyona nto ilawula ukukhanya kwizicubu zebhayoloji, ngoko ke umsinga wamaza owamkelwe yinkqubo kufuneka uthintele incopho yokufunxa amanzi ukuze kufumaneke ngcono ulwazi lokufunxa ukukhanya kwento ekujoliswe kuyo. Ke ngoko, ngaphakathi koluhlu olusondeleyo lwe-infrared spectrum ye-600-950nm, ezona nxalenye ziphambili zethishu yeminwe yomntu ekwazi ukufunxa ukukhanya ibandakanya amanzi egazini, i-O2Hb (i-hemoglobin ene-oxygen), i-RHb (i-hemoglobin encitshisiweyo) kunye ne-peripheral skin melanin kunye nezinye izicubu.
Ngoko ke, sinokufumana ulwazi olusebenzayo lokugxininiswa kwecandelo eliza kulinganiswa kwisicatshulwa ngokuhlalutya idatha ye-spectrum emission. Ke xa sinogxininiso lwe-O2Hb kunye ne-RHb, siyayazi i-oxygen saturation.Ukuhluthwa kweoksijini SpO2yipesenti yomthamo we-oksijini-ebopheleleke kwi-oksijini hemoglobin (HbO2) egazini njengepesenti ye-hemoglobin ebophelelayo iyonke (Hb), ukuxinwa kwe-blood oxygen pulse kutheni kubizwa ngokuba yi-pulse oximeter? Nantsi ingcamango entsha: ukuhamba kwegazi umthamo we-pulse wave. Ngexesha lomjikelo ngamnye wentliziyo, ukufinyela kwentliziyo kubangela ukuba uxinzelelo lwegazi lunyuke kwimithambo yegazi yengcambu ye-aorta, evula udonga lwemithambo yegazi. Ngokuchasene noko, i-diastole yentliziyo ibangela ukuba uxinzelelo lwegazi luwele kwimithambo yegazi yengcambu ye-aorta, ebangela ukuba udonga lwegazi lube lukhuni. Ngokuphindwa ngokuqhubekayo komjikelezo wentliziyo, utshintsho oluqhubekayo loxinzelelo lwegazi kwimizila yegazi yengcambu ye-aortic iya kudluliselwa kwiinqanawa ezisezantsi ezidityaniswe nayo kunye nakwinkqubo yonke ye-arterial, ngaloo ndlela yenze ukwanda okuqhubekayo kunye nokunciphisa udonga lwe-arterial vascular wall. Oko kukuthi, ukubetha kwentliziyo ngamaxesha athile kudala amaza e-pulse kwi-aorta ejikeleza phambili ecaleni kweendonga zemithambo yegazi kuyo yonke inkqubo ye-arterial. Ngalo lonke ixesha intliziyo isanda kwaye idibanisa, utshintsho kwixinzelelo kwi-arterial system luvelisa i-period pulse wave. Yile nto siyibiza ngokuba liza le-pulse wave. I-Pulse wave inokubonisa ulwazi oluninzi lwe-physiological olufana nentliziyo, uxinzelelo lwegazi kunye nokuhamba kwegazi, olunokubonelela ngolwazi olubalulekileyo ekubhaqweni okungahlaseli kweeparamitha ezithile zomzimba womntu.
Kwezamayeza, i-pulse wave ihlala yohlulwa ibe ngamaza oxinzelelo lwe-pulse kunye ne-volume pulse wave iindidi ezimbini. I-Pressure pulse wave ikakhulu imele ukusasazwa koxinzelelo lwegazi, ngelixa i-volume wave wave imele utshintsho lwamaxesha athile ekuhambeni kwegazi. Xa kuthelekiswa noxinzelelo lwe-pulse wave, i-volumetric pulse wave iqulethe ulwazi olubaluleke ngakumbi lwentliziyo efana nemithambo yegazi kunye nokuhamba kwegazi. Ukufunyaniswa okungaxhatshazwayo kokuhamba kwegazi okuqhelekileyo umthamo we-pulse wave kunokufezekiswa ngokulandelwa kwe-photoelectric volumetric pulse wave. Ilanga elithile lokukhanya lisetyenziselwa ukukhanyisa indawo yokulinganisa umzimba, kwaye umqadi ufikelela kwinzwa ye-photoelectric emva kokubonakaliswa okanye ukuhanjiswa. I-beam efunyenweyo iya kuthwala ulwazi olusebenzayo lweempawu ze-volumetric pulse wave. Ngenxa yokuba umthamo wegazi uguquka ngamaxesha athile kunye nokwandiswa kunye nokucutheka kwentliziyo, xa intliziyo ye-diastole, umthamo wegazi ungowona umncinci, ukufunxa igazi ekukhanyeni, inzwa yafumanisa ukukhanya okukhulu kokukhanya; Xa intliziyo inkontileka, umthamo uphezulu kwaye ukukhanya kokukhanya okufunyenwe yinzwa kuncinci. Ekubhaqweni okungathintekiyo kweminwe kunye nokuhamba kwegazi umthamo we-pulse wave njengedatha yokulinganisa ngokuthe ngqo, ukukhethwa kwendawo yokulinganisa i-spectral kufuneka kulandele le migaqo ilandelayo.
1. Imithambo yegazi kufuneka ibe yinto eninzi kakhulu, kwaye umlinganiselo wolwazi olusebenzayo olufana ne-hemoglobin kunye ne-ICG kulwazi olupheleleyo lwezinto eziphathekayo kwi-spectrum kufuneka luphuculwe.
2. Ineempawu ezicacileyo zokutshintsha komthamo wegazi ukuqokelela ngokufanelekileyo umqondiso we-volume pulse wave
3. Ukuze ufumane i-spectrum yabantu ngokuphindaphinda kakuhle kunye nokuzinza, iimpawu ze-tissue azichaphazeli kangako ukungafani komntu ngamnye.
4. Kulula ukuphumeza ukubonwa kwe-spectral, kwaye kulula ukwamkelwa ngumxholo, ukwenzela ukuba ugweme izinto eziphazamisayo ezifana nesantya sentliziyo esheshayo kunye nokunyakaza kwesikhundla sokulinganisa okubangelwa yimvakalelo yoxinzelelo.
Umzobo weSchematic wokuhanjiswa kwemithambo yegazi entendeni yomntu Indawo yengalo ayinakukwazi ukubona i-pulse wave, ngoko ayifanelekanga ukufunyaniswa kokuhamba kwegazi umthamo we-pulse wave; Isihlahla sikufuphi nomthambo we-radial, i-pressure pulse wave signal yomelele, ulusu lulula ukuvelisa ukungcangcazela koomatshini, kunokukhokelela kwisignali yokufumanisa ukongeza kwi-volume pulse wave nayo iphethe ulwazi lwe-skin reflection pulse, kunzima ukuchaza ngokuchanekileyo iimpawu zokutshintsha umthamo wegazi, ayifanelekanga indawo yokulinganisa; Nangona intende yesandla yenye yeendawo eziqhelekileyo zokuzoba igazi leklinikhi, ithambo layo lingqindilili kunomnwe, kwaye i-pulse wave amplitude yomthamo wesundu oqokelelwe ngokubonakaliswa kwe-diffuse reflection isezantsi. Umzobo 2-5 ubonisa ukuhanjiswa kwemithambo yegazi entendeni. Ukuqwalasela umzobo, kunokubonwa ukuba kukho amanethiwekhi amaninzi e-capillary kwindawo engaphambili yomnwe, enokubonisa ngokufanelekileyo umxholo we-hemoglobin emzimbeni womntu. Ngaphezu koko, esi sikhundla sineempawu ezicacileyo zokutshintsha umthamo wegazi, kwaye yindawo efanelekileyo yokulinganisa i-volume wave wave. Izihlunu kunye nezicubu zethambo zeminwe zincinci, ngoko ke impembelelo yolwazi lokuphazamiseka kwemvelaphi incinci. Ukongeza, incam yomnwe ilula ukulinganisa, kwaye isifundo asinalo umthwalo wengqondo, olungele ukufumana isignali ephezulu ezinzileyo ye-signal-to-noise ratio spectral. Umnwe womntu unethambo, isikhonkwane, ulusu, izicubu, igazi le-venous kunye negazi le-arterial. Kwinkqubo yokusebenzisana nokukhanya, umthamo wegazi kwi-artery ye-peripheral yomnwe uguquka ngokubetha kwentliziyo, okukhokelela ekutshintsheni umlinganiselo wendlela ye-optical. Ngelixa amanye amacandelo ahlala rhoqo kuyo yonke inkqubo yokukhanya.
Xa i-wavelength ethile yokukhanya isetyenziswe kwi-epidermis ye-fingertip, umnwe unokuthathwa njengomxube, kubandakanywa namacandelo amabini: i-static matter (indlela ye-optical isigxina) kunye ne-dynamic matter (i-optical path paths with volume of the material). Xa ukukhanya kutsalwa yizicubu zeminwe, ukukhanya okugqithisiweyo kufunyanwa yi-photodetector. Ubukhulu bokukhanya okugqithisiweyo okuqokelelwe yinzwa ngokucacileyo kuyancipha ngenxa yokuxhamla kwamacandelo eethishu ezahlukahlukeneyo zeminwe yomntu. Ngokwalo phawu, imodeli elinganayo yokufunxa ukukhanya kweminwe isekwe.
Umntu ofanelekileyo:
Incam yeminwe yokubetha i-oximeterilungele abantu bayo yonke iminyaka, kubandakanywa abantwana, abantu abadala, abalupheleyo, abaguli abanesifo senhliziyo, uxinzelelo lwegazi, i-hyperlipidemia, i-cerebral thrombosis kunye nezinye izifo ze-vascular kunye nezigulane ezine-asthma, i-bronchitis, i-bronchitis engapheliyo, isifo senhliziyo ye-pulmonary kunye nezinye izifo zokuphefumla.
Ixesha lokuposa: Jun-17-2022
