I-fingertip pulse oximeter yasungulwa nguMillikan ngeminyaka yoo-1940 ukujonga uxinano lweoksijini egazini lemithambo yegazi, uphawu olubalulekileyo lobunzima be-COVID-19.Yonker ngoku ichaza indlela esebenza ngayo i-pulse oximeter yeminwe?
Iimpawu zokufunxwa kwe-spectral kwizicubu zebhayoloji: Xa ukukhanya kukhanyiselwa kwizicubu zebhayoloji, impembelelo yezicubu zebhayoloji ekukhanyeni inokwahlulwahlulwa ibe ngamacandelo amane, kubandakanya ukufunxwa, ukusasazeka, ukubonakalisa kunye nokukhanya okukhanyayo. Ukuba ukusasazeka akubandakanyiwe, umgama ohamba ukukhanya kwizicubu zebhayoloji ulawulwa kakhulu kukufunxwa. Xa ukukhanya kungena kwezinye izinto ezicacileyo (eziqinileyo, ezingamanzi okanye ezinegesi), ubunzulu bokukhanya buyehla kakhulu ngenxa yokufunxwa okujoliswe kuko kwezinye izinto ezithile ze-frequency, okuyimeko yokufunxwa kokukhanya zizinto. Ubungakanani bokukhanya into efunxwa bubizwa ngokuba yi-optical density yayo, eyaziwa ngokuba yi-absorbance.
Umzobo weskimu wokufunxwa kokukhanya yizinto kuyo yonke inkqubo yokusasazwa kokukhanya, ubungakanani bamandla okukhanya afunxwa yinto buhambelana nezinto ezintathu, ezikukukhanya okunamandla, umgama wendlela yokukhanya kunye nenani lamasuntswana afunxwayo ukukhanya kwicandelo elinqamlezileyo lendlela yokukhanya. Ngokwesiseko sezinto ezilinganayo, inani lendlela yokukhanya amasuntswana afunxwayo ukukhanya kwicandelo elinqamlezileyo anokuthathwa njengamasuntswana afunxwayo ukukhanya ngeyunithi nganye, oko kukuthi ukufunxwa kokukhanya kwezinto, kunokufumana umthetho webhiya ye-lambert: kunokutolikwa njengoxinzelelo lwezinto kunye nobude bendlela ye-optical ngeyunithi nganye yobuninzi be-optical, amandla okukhanya okufunxwa kwezinto ukuphendula kuhlobo lokukhanya kokufunxwa kwezinto. Ngamanye amazwi, imilo ye-absorption spectrum curve yento efanayo iyafana, kwaye indawo epheleleyo yencochoyi yokufunxwa iya kutshintsha kuphela ngenxa yokufunxwa okwahlukileyo, kodwa indawo ehambelanayo iya kuhlala ingatshintshanga. Kwinkqubo yokufunxwa, ukufunxwa kwezinto zonke kwenzeka kumthamo wecandelo elinye, kwaye izinto ezifunxwayo azinxulumananga, kwaye akukho zikhompawundi ze-fluorescent ezikhoyo, kwaye akukho nto itshintsha iipropati ze-medium ngenxa yemitha yokukhanya. Ngoko ke, kwisisombululo esineenxalenye ze-N absorption, i-optical density iyongezwa. I-additivity ye-optical density inika isiseko sethiyori sokulinganisa ubungakanani bezixhobo ezifunxayo kwimixube.
Kwi-biological tissue optics, ummandla we-spectral ongama-600 ~ 1300nm udla ngokubizwa ngokuba "yifestile ye-biological spectroscopy", kwaye ukukhanya okukule band kunentsingiselo ekhethekileyo kunyango oluninzi lwe-spectral olwaziwayo nolungaziwayo kunye nokuxilongwa kwe-spectral. Kummandla we-infrared, amanzi aba yinto elawulayo efunxa ukukhanya kwizicubu ze-biological, ngoko ke ubude be-wavelength obusetyenziswa yinkqubo kufuneka buphephe incopho yokufunxa amanzi ukuze kufumaneke ngcono ulwazi lokufunxa ukukhanya kwento ekujoliswe kuyo. Ke ngoko, ngaphakathi koluhlu lwe-spectrum olukufutshane lwe-infrared oluyi-600-950nm, izinto eziphambili zezicubu zomnwe womntu ezinomthamo wokufunxa ukukhanya ziquka amanzi egazini, i-O2Hb (i-oxygenated hemoglobin), i-RHb (i-reduced hemoglobin) kunye ne-peripheral skin melanin kunye nezinye izicubu.
Ngoko ke, singafumana ulwazi olusebenzayo loxinzelelo lwecandelo eliza kulinganiswa kwithishu ngokuhlalutya idatha ye-emission spectrum. Ngoko ke xa sine-O2Hb kunye ne-RHb concentrations, siyazi i-oxygen saturation.Ukwanda kweoksijini SpO2Ngaba yipesenti yomthamo we-hemoglobin ene-oxygenated hemoglobin (HbO2) egazini njengepesenti ye-hemoglobin iyonke ebophayo (Hb), uxinano lwe-oxygen pulse yegazi, ngoko kutheni ibizwa ngokuba yi-pulse oximeter? Nantsi ingcamango entsha: umthamo wokuhamba kwegazi, i-pulse wave. Ngexesha lomjikelo ngamnye wentliziyo, ukuxinana kwentliziyo kubangela ukuba uxinzelelo lwegazi lunyuke kwimithambo yegazi yengcambu ye-aortic, eyandisa udonga lwemithambo yegazi. Ngokwahlukileyo koko, i-diastole yentliziyo ibangela ukuba uxinzelelo lwegazi luwe kwimithambo yegazi yengcambu ye-aortic, ebangela ukuba udonga lwemithambo yegazi lunciphe. Ngokuphindaphindwa okuqhubekayo komjikelo wentliziyo, utshintsho oluqhubekayo loxinzelelo lwegazi kwimithambo yegazi yingcambu ye-aortic luya kudluliselwa kwimithambo yegazi esezantsi edibene nayo kwanakwinkqubo yonke yemithambo yegazi, ngaloo ndlela kwakheka ukwanda okuqhubekayo kunye nokuncipha kodonga lonke lwemithambo yegazi. Oko kukuthi, ukubetha rhoqo kwentliziyo kudala amaza e-pulse kwi-aorta ahamba phambili eludongeni lwemithambo yegazi kulo lonke inkqubo yemithambo yegazi. Ixesha ngalinye intliziyo ikhula kwaye incipha, utshintsho kuxinzelelo kwinkqubo yemithambo yegazi luvelisa amaza e-pulse aqhubekayo. Oku kubizwa ngokuba yi-pulse wave. I-pulse wave inokubonakalisa ulwazi oluninzi lwe-physiological olufana nentliziyo, uxinzelelo lwegazi kunye nokuhamba kwegazi, olunokubonelela ngolwazi olubalulekileyo lokufumanisa iiparameter ezithile zomzimba womntu ngendlela engangenisi ntsholongwane.
Kwizonyango, i-pulse wave idla ngokwahlulwahlulwa ibe yi-pressure pulse wave kunye ne-volume pulse wave ezimbini. I-pressure pulse wave imele ikakhulu ukudluliselwa koxinzelelo lwegazi, ngelixa i-volume pulse wave imele utshintsho oluqhubekayo ekuhambeni kwegazi. Xa kuthelekiswa ne-pressure pulse wave, i-volumetric pulse wave iqulethe ulwazi olubaluleke ngakumbi lwentliziyo olufana nemithambo yegazi yomntu kunye nokuhamba kwegazi. Ukufunyanwa okungangeniyo komthamo wegazi oqhelekileyo kunokufezekiswa ngokulandelela i-photoelectric volumetric pulse wave. I-wave ethile yokukhanya isetyenziselwa ukukhanyisa inxalenye yokulinganisa yomzimba, kwaye umqadi ufikelela kwi-photoelectric sensor emva kokubonakalisa okanye ukudluliselwa. Umqadi ofunyenweyo uya kuthwala ulwazi olusebenzayo lwe-volumetric pulse wave. Ngenxa yokuba umthamo wegazi utshintsha rhoqo ngokwandiswa kunye nokucutheka kwentliziyo, xa intliziyo i-diastole, umthamo wegazi ngowona mncinci, ukufunxwa kwegazi kokukhanya, i-sensor ibone ubukhulu bokukhanya; Xa intliziyo ifinyela, umthamo uphezulu kwaye amandla okukhanya afunyenwe yi-sensor aphantsi. Ekuchongweni okungangeniyo kweminwe nge-blood flow volume wave njengedatha yokulinganisa ngqo, ukukhethwa kwendawo yokulinganisa i-spectral kufuneka kulandele le migaqo ilandelayo.
1. Imithambo yegazi kufuneka ibe mininzi ngakumbi, kwaye umlinganiselo wolwazi olusebenzayo olufana ne-hemoglobin kunye ne-ICG kulwazi olupheleleyo lwezinto ezibonakalayo kwi-spectrum kufuneka uphuculwe.
2. Ineempawu ezicacileyo zokutshintsha komthamo wokuhamba kwegazi ukuze iqokelele ngempumelelo isandisi se-pulse wave
3. Ukuze kufumaneke i-spectrum yomntu enokuphindwa okuhle kunye nokuzinza, iimpawu zezicubu azichaphazeleki kangako kumahluko ohlukeneyo.
4. Kulula ukwenza ubhaqo lwe-spectral, kwaye kulula ukwamkelwa ngumntu ochaphazelekayo, ukuze kuthintelwe ukuphazamiseka okufana nokubetha kwentliziyo ngokukhawuleza kunye nokuhamba kwesimo sokulinganisa okubangelwa yimvakalelo yoxinzelelo.
Umzobo wesicwangciso sokusasazeka kwemithambo yegazi kwisandla somntu Indawo yengalo ayinakukwazi ukubona i-pulse wave, ngoko ke ayifanelekanga ukufumanisa i-pulse wave yomthamo wokuhamba kwegazi; Isandla sikufutshane nomthambo we-radial, i-pressure pulse wave signal inamandla, ulusu kulula ukuvelisa ukungcangcazela koomatshini, kunokukhokelela kwi-signal yokufumanisa ukongeza kwi-volume pulse wave ikwaphethe ulwazi lwe-skin reflection pulse, kunzima ukuchaza ngokuchanekileyo iimpawu zotshintsho lomthamo wegazi, ayifanelekanga kwindawo yokulinganisa; Nangona isundu linye yeendawo eziqhelekileyo zokudweba igazi, ithambo lalo likhulu kunomnwe, kwaye i-pulse wave amplitude yomthamo wesundu eqokelelwe yi-diffuse reflection iphantsi. Umfanekiso 2-5 ubonisa ukusasazwa kwemithambo yegazi kwisandla. Ukujonga umfanekiso, kunokubonwa ukuba kukho iinethiwekhi ezininzi ze-capillary kwinxalenye engaphambili yomnwe, enokubonakalisa ngempumelelo umxholo we-hemoglobin emzimbeni womntu. Ngaphezu koko, le ndawo ineempawu ezicacileyo zotshintsho lomthamo wokuhamba kwegazi, kwaye yindawo efanelekileyo yokulinganisa i-volume pulse wave. Izicubu zemisipha kunye namathambo zeminwe zincinci, ngoko ke impembelelo yolwazi lokuphazamiseka kwangasemva incinci. Ukongeza, incam yomnwe kulula ukuyilinganisa, kwaye umntu akanalo uxanduva lwengqondo, nto leyo enceda ekufumaneni isignali ye-spectral ezinzileyo enomlinganiselo ophezulu wesignali-kwingxolo. Umnwe womntu uqulathe amathambo, iinzipho, ulusu, izicwili, igazi lemithambo yegazi kunye negazi lemithambo yegazi. Kwinkqubo yokusebenzisana nokukhanya, umthamo wegazi kumthambo wemithambo yegazi ojikelezayo womnwe uyatshintsha ngokubetha kwentliziyo, nto leyo ebangela utshintsho kwindlela yokulinganisa ye-optical. Ngelixa ezinye izinto zihlala zihleli kuyo yonke inkqubo yokukhanya.
Xa kusetyenziswa ubude bokukhanya obuthile kwi-epidermis yencam yomunwe, umnwe ungathathwa njengomxube, kuquka iindawo ezimbini: i-static matter (indlela ye-optical ayiguquguquki) kunye ne-dynamic matter (indlela ye-optical iyatshintsha ngokwevolumu yezinto). Xa ukukhanya kutsalwa yi-tissue yencam yomunwe, ukukhanya okudlulisiweyo kwamkelwa yi-photodetector. Ubungakanani bokukhanya okudlulisiweyo okuqokelelwe yi-sensor buyancipha ngokucacileyo ngenxa yokufunxwa kwezixhobo ezahlukeneyo zezicubu zeminwe yomntu. Ngokwale mpawu, imodeli efanayo yokufunxwa kokukhanya kweminwe iyasekwa.
Umntu ofanelekileyo:
I-oximeter ye-pulse yeminweifanelekile kubantu bayo yonke iminyaka, kuquka abantwana, abantu abadala, abantu abadala, izigulane ezinesifo sentliziyo, uxinzelelo lwegazi oluphezulu, i-hyperlipidemia, i-cerebral thrombosis kunye nezinye izifo zemithambo yegazi kunye nezigulane ezine-asthma, i-bronchitis, i-bronchitis engapheliyo, isifo sentliziyo semiphunga kunye nezinye izifo zokuphefumla.
Ixesha lokuthumela: Juni-17-2022
