Ukulinganisa izinga lokugcwala komoyampilo kuwukuhlola okwenza kube nokwenzeka ukuhlola umsebenzi we-hematosis: umoya-mpilo wegazi. Lokhu kuhlaziywa kokugcwala komoyampilo kusetshenziswa ikakhulukazi kubantu abane-pathology yokuphefumula.

Igazi linikeza umoya-mpilo kuzo zonke izicubu futhi lithwala i-carbon dioxide liyise emaphashini ukuze likhishwe emzimbeni. Inani elincane lomoya-mpilo lithwalwa yi-plasma. Iningi lawo lithwalwa yi-hemoglobin emangqamuzaneni abomvu egazi.

I-oxygen yegazi ibonakala ngezindlela ezintathu:

• iphesenti lokugcwala kwe-hemoglobin ye-transporter eyinhloko (SaO2),
• umfutho owenziwe egazini elincibilikile (PaO2)
• inani layo egazini (CaO2).

Ekungasebenzi kahle kokuphefumula, igazi liqukethe umoya-mpilo omncane kanye ne-carbon dioxide eyengeziwe. Izinga le-oxygenation lingalinganiswa ngezindlela ezimbili: ukugcwala komoyampilo (i-SaO2, kukalwa ngegazi le-arterial, i-SpO2 ilinganiswa nge-pulse oximeter noma i-saturometer) kanye nokucindezela kwengxenye ye-oxygen (PaO2).

Ukugcwala komoyampilo (i-SaO2) kumelela ingxenye yephesenti ye-hemoglobin egcwele umoya-mpilo (i-oxyhemoglobin) ngokuhlobene nenani eliphelele le-hemoglobin ekhona egazini. Ukugcwala komoya-mpilo kulinganiswa ukuze kuhlolwe umsebenzi we-hematosis: ukufakwa kwe-oxygen egazini.

Izinga lokugcwala komoyampilo lingalinganiswa ngezindlela ezimbili:

Ngokuthatha igazi le-arterial (izilinganiso zegesi legazi).

Lokhu kuhilela ukuhlola igazi emithanjeni yegazi. Iwukuphela kwendlela evumela ukukala okuthembekile nokuqinisekile kwamagesi egazi. Ukugcwaliseka kokulinganisa kwegesi ye-arterial kuvumela ukuhlaziya ibhalansi ye-acid-base (pH) kanye nesilinganiso somfutho we-arterial ku-oxygen (PaO2) kanye ne-carbon dioxide (PaCO2) okwenza kube nokwenzeka ukwazi ukuphefumula kombuso. Ukugcwaliswa kwe-hemoglobin komoya-mpilo okukalwa ngesampula yegazi le-arterial kuvezwa ku-Sao2. Ukugcwala komoya-mpilo kukalwa ngokuqondile kumangqamuzana egazi abomvu.

Nge-pulse oximeter noma i-saturometer (indlela elula yokusebenzisa)

I-pulse oximeter noma i-oximeter iyithuluzi elingahlaseli ukugcwala komoyampilo egazini. Le divayisi isetshenziswa kakhulu ezibhedlela ukuqapha iziguli ezinenkinga yokuphefumula noma ezisebenzisa izisekelo zokuphefumula ezihlaselayo noma ezingavaleli (ukwelashwa komoyampilo). Ifakwe i-emitter kanye nesamukeli sokukhanya esenza kube nokwenzeka ukunquma ukugcwala komoyampilo egazini.

Idlulisa umsebe wokukhanya ngezicubu, ngokuvamile umunwe noma uzwane kubantu abadala, kodwa futhi ikhala noma indlebe, noma isandla noma unyawo ezinganeni ezincane. Ukugcwala komoyampilo kwe-hemoglobin okukalwa nge-pulse oximetry kuvezwa njenge-SpO2 (i-p ekhombisa ukugcwala kokushaya kwenhliziyo). Sikhuluma nge-pulsed saturation ye-hemoglobin ne-oxygen.

Kunezinkomba ezimbalwa zokulinganisa izinga lokugcwala komoyampilo nge-saturometer kubantu abadala:

• ngesikhathi sokulaliswa kwezinzwa noma ekamelweni lokuqapha ngemva kokuhlinzwa
• Eminyango yezokwelapha eziphuthumayo
• Ekunakekelweni okukhulu, ikakhulukazi kubantu abafakwe umoya omncane noma okungenzeka babe.

Ezinganeni, ukukalwa kwezinga lokugcwala komoyampilo nakho kunezinkomba ezimbalwa:

• ukuhlolwa kobunzima be-pathology yokuphefumula (i-bronchiolitis, i-pneumonia, i-asthma, njll.)
• ukuhlolwa kobunzima be-bronchiolitis yezingane; ukugcwala okungaphansi kwama-94% kungenye yezinkomba zobunzima
• ukuhlolwa kokusebenza kwe-aerosol
• ukutholakala kwesifo senhliziyo esingase sibe khona kusana olusanda kuzalwa olune-cyanotic

Ukulinganisa kwegesi ye-arterial kwenziwa lapho kukhona isimo esinzima sokuphefumula futhi kukhona ukusola kwesifo esikhulu se-metabolic.

Ukugcwala komoyampilo okuvamile kumuntu onempilo kuphakathi kuka-95% no-100% kuye ngeminyaka. I-SpO2 (Ukugcwaliswa kwe-pulse kukalwa nge-pulse oximeter). Ayenele ngaphansi kwama-95%. Sikhuluma nge-hypoxemia. Umqondo we-hypoxemia usebenza kunoma yikuphi ukuntuleka komoya-mpilo egazini ngakho-ke ngokushesha nje lapho i-SpO2 ingaphansi kwama-95%. Umkhawulo wama-90% uphawula i-hypoxemia ehambisana nokulingana nokwehluleka ukuphefumula.

Ukugcwaliswa kwe-oksijini okujwayelekile kwe-arterial (SaO2) kuphakathi kuka-96% no-98% kumuntu osemusha omdala angama-95% kumuntu oneminyaka engaphezu kwengu-70 ubudala. Uma ingaphansi kuka-90%, umuntu kuthiwa usephelelwe amandla. I-Desaturation iphinda ihambisane nokwehla kwamaphoyinti angu-4 okugcwalisa uma kuqhathaniswa nenani eliyisisekelo (isibonelo phakathi nomzamo).

I-SpO2 “evamile” enganeni ihambisana nenani elikhulu kuno-95%. Izinga le-SpO2 elingaphansi kuka-94% enganeni liwumbandela wokungathí sina futhi liholela ekulalisweni esibhedlela. Ukulinganisa i-SpO2 kubaluleke kakhulu ezinganeni, ngoba ingane ibonakala kuphela i-cyanotic (ibala eliluhlaza okwesibhakabhaka) lapho i-SaO2 ingaphansi kuka-75% futhi ngenxa yokuthi ukulinganisa kwegesi ye-arterial akuvamile ukwenziwa ezinganeni. I-pulse oximeter ibalulekile ukuze kutholwe i-hypoxia yokuqala.

Sikhuluma nge-hypoxemia lapho inani lokugcwala komoyampilo lingaphansi kwama-93%. Ingozi eyinhloko yileyo yokuhlupheka kwamangqamuzana (ischemia) okubangelwa ukuntuleka komoyampilo okwanele ezicutshini ezihlukahlukene zomzimba. I-acute hypoxemia ingenzeka ngemva kokwanda kakhulu kwesifuba somoya, ukuhluleka kwenhliziyo okunamandla, inyumoniya noma ukwanda okunamandla kwe-Chronic Obstructive Pulmonary Disease (COPD), kulandela ukuvaleka kwamaphaphu, ukuphuma kwe-pleural, i-pneumothorax.

I-Hypoxemia (izinga lokugcwala komoyampilo elingaphansi kwama-93%) libonakaliswa ukuphelelwa umoya, ukuphefumula okungajulile ngokushesha, isikhumba esiluhlaza okwesibhakabhaka (i-cyanosis) kodwa zonke lezi zimpawu azicacisi futhi azizwela kakhulu kune-pulse oximetry.

I-COVID-19 ingabangela izinga eliphansi lokugcwala komoyampilo. Amacala amabi kakhulu e-COVID angadala inyumoniya ebangela i-acute Respiratory Distress Syndrome. Izimpawu zicashile ekuqaleni. Yingakho odokotela bengakwazi ukuqapha izinga lokugcwala komoyampilo nge-oximeter. Ukuphefumula kanzima kanye nokuphelelwa umoya kuyizimpawu okufanele ushayele abezimo eziphuthumayo.

Isexwayiso: Ukusebenzisa i-pulse oximeter nakho kuveza ubungozi bamaphutha futhi kuhle ukufunda ukuthi ungayisebenzisa kanjani nochwepheshe bezempilo.

Ukunikezwa komoyampilo omningi ngesikhathi sokwelashwa komoyampilo kungaholela ku-hyperoxia. I-Hyperoxia iyingozi kubantu abanenkinga yokuphefumula.

Uma kwenzeka i-hypoxemia (i-oxygen saturation ngaphansi kwama-93), ukwelashwa nge-oxygen therapy kungase kusetshenziswe. Umoya-mpilo ungalawulwa ngomzila wamakhala (izibuko) noma imizila yamakhala neyomlomo (izifihla-buso) kodwa futhi nangokungenisa umoya okwenziwayo (i-ventilator, intubation) noma ngokujikeleza kwe-extracorporeal (ECMO). Inani le-oxygen elethwa liqondiswa amagesi egazi emithanjeni noma i-pulse oximetry ukuze kugcinwe i-Pao2 phakathi kuka-60-80 mmHg (92-100% saturation) ngaphandle kokubangela ubuthi bwe-oksijeni.