I-methylene blue ye-methemoglobinemia: kungani isetshenziswa ezibhedlela

Isiguli sifika sinezindebe ezinombala ompunga oluhlaza okwesibhakabhaka njengetshe le-slate, siphefumula ngokushesha, siphendula kancane. Umshini wokuqapha uthi ukugcwala komoya-mpilo egazini kungamaphesenti angu-85. Umhlengikazi wandisa umoya-mpilo. Inani aliguquki. Kuthathwa igazi, liphume linsundu njengoshokoledi, futhi lihlala linsundu lapho lichayekwa emoyeni. Lokho kulandelana kwezehlakalo kuyisiqalo esijwayelekile sokunakekelwa kwe-methemoglobinemia nge-methylene blue, futhi kubonisa ukuthi kungani lesi simo sidida imindeni nemishini.

Inkinga ayikho emaphashini. Iku-ayoni engaphakathi kwe-hemoglobin.

Izimo ezimbili ze-athomu efanayo ye-ayoni

I-molecule ngayinye ye-hemoglobin ithwala i-ayoni esesimweni se-ferrous, esibhalwa ngokuthi Fe2+. Kuleso simo ibopha umoya-mpilo emaphashini bese iwukhulula ezicutshini. Amakhemikhali enza i-oxidation angasusa elinye i-electron kuleyo ayoni, ayiguqulele esimweni se-ferric, Fe3+. Into enombala evelayo yi-methemoglobin. I-ayoni esesimweni se-ferric ayikwazi ukubopha umoya-mpilo, futhi okubi nakakhulu, yenza izindawo ezisele ze-ferrous ku-molecule efanayo zibambe umoya-mpilo wazo ngokuqinile kakhulu, ngakho kukhululwa umoya-mpilo omncane lapho udingeka khona.

Igazi elinempilo ligcina i-methemoglobin ingaphansi kwamaphesenti acishe abe ngu-1 ngoba i-enzyme yokulungisa isebenza njalo. Indlela eyinhloko yokulungisa isebenzisa i-NADH ne-cytochrome b5 reductase, inikwe amandla yi-glycolysis evamile engqamuzaneni elibomvu legazi. Enye indlela esekelayo isebenzisa i-NADPH, kodwa ngaphansi kwezimo ezivamile yenza umsebenzi omncane. Izimpawu zihambisana cishe nephesenti, nakuba i-anemia noma isifo senhliziyo namaphaphu kungabangela ukuthi inani eliphansi libe yingozi. Amanani aseduze kwamaphesenti angu-10 kuya ku-20 angabangela i-cyanosis ebonakalayo nokukhathala. Amanani angaphezu kwamaphesenti angu-30 avame ukubangela ikhanda elibuhlungu, ukuphelelwa umoya nokudideka. Amanani aseduze kwamaphesenti angu-70 avame ukubulala. La manani ayizigaba, awazona iziqinisekiso, ngoba okubalulekile ukufika komoya-mpilo ezicutshini, hhayi inani laselabhorethri kuphela.

Izimbangela ezivamile ezingatholakali ngokuzalwa zihlanganisa i-dapsone, ama-nitrite nama-nitrate, izinhlanganisela ze-aniline, nemithi yokubulala izinzwa endaweni ethile njenge-benzocaine ne-prilocaine. Ukushoda kwama-enzyme umuntu azalwa nakho kukhona kodwa akuvamile. Izimo eziningi ezibonwa ezibhedlela azitholakali ngokuzalwa, okusho ukuthi isinyathelo sokuqala sokwelapha sihlala siwukumisa ukuchayeka entweni eyimbangela.

Isithuthi ama-electron esisetshenziswa izibhedlela

I-methylene blue ayihlinzeki ngomoya-mpilo. Ihlinzeka ngokuthuthwa kwama-electron. Ngaphakathi kwengqamuzana elibomvu legazi, i-enzyme isebenzisa i-NADPH ukushintsha udayi oluhlaza okwesibhakabhaka ngokuwunika ama-electron, uwenze ube yisimo sawo esingenambala, i-leucomethylene blue. Leso simo esingenambala sibe sesidlulisela ama-electron ku-ayoni esesimweni se-ferric ngaphandle kokusebenzisa i-enzyme, sibuyisele i-hemoglobin esimweni se-ferrous, bese sibuyela esimweni esiluhlaza okwesibhakabhaka. Udayi uphinda lo mjikelezo. Lokhu kudlulisana ngokwako kuchazwa endleleni i-methylene blue ehambisa ngayo ama-electron phakathi kwabanikeli nabamukeli, futhi isimo esingenambala esithole ama-electron sichazwa ekuqhathanisweni kwe-methylene blue ne-leucomethylene blue.

Le ndlela yokusebenza ichaza imingcele emibili emangaza abasanda kuyazi. Okokuqala, lesi sithuthi sidinga i-NADPH, futhi i-NADPH engqamuzaneni elibomvu legazi incike ku-glucose-6-phosphate dehydrogenase, i-G6PD. Uma kukhona ukushoda kwe-G6PD, udayi ungase ungakwazi ukuguqukela esimweni sawo esisebenzayo, ngesikhathi wona ngokwawo wengeza umthwalo we-oxidation. Yingakho ilebula yomkhiqizo osetshenziswa esibhedlela ibala ukushoda kwe-G6PD njengesimo okungafanele usetshenziswe kuso. Okwesibili, i-methylene blue ngokwayo yenza i-oxidation lapho imithamo eqoqekayo iphakeme. Uma isiyonke isidlula cishe ku-7 mg nge-kg, noma ngezinye izikhathi ngaphansi kwalokho uma imithamo iphindwa, ingakhuphula i-methemoglobin futhi ibhubhise amangqamuzana abomvu egazi kunokuba iwalungise. Udayi owengeziwe awusho ukusindisa okwengeziwe. Ibanga lomthamo livinjelwe ngamabomu.

Kungani ukuhlola okusobala kudukisa

Imindeni ivame ukufuna ukuhlola kwe-methylene blue engakwenza ekhaya. Akukho ukuhlola okunjalo. Le nkulumo ngokuvamile isho uchungechunge lokuhlola lokuhlonza i-methemoglobinemia okusolwa ukuthi ikhona, futhi lokho kuhlola kufanele kwenziwe elabhorethri.

Ama-pulse oximeter ajwayelekile afunda ubude bamaza okukhanya obubili kuphela. Njengoba i-methemoglobin ikhuphuka, ukumuncwa kokukhanya kulobo bude bamaza obubili kuyasondelana, futhi ukugcwala komoya-mpilo okubonisiwe kusondela kumaphesenti acishe abe ngu-85 kungakhathaliseki ukuthi isimo sangempela siyini. Umoya-mpilo owengeziwe awulungisi lelo nani ngoba inzwa ayikali lokho okungahambi kahle. Ingcindezi yomoya-mpilo egazini lemithambo ephuma enhliziyweni, i-PaO2, ingabonakala ivamile ngesikhathi esifanayo, ngoba ikala umoya-mpilo oncibilike ku-plasma kunomoya-mpilo othwalwa yi-hemoglobin. Ngakho umshini wokuhlaziya amagesi egazini obala ukugcwala komoya-mpilo nge-PaO2 ungabika inani eliduduzayo kuyilapho isiguli sisene-cyanosis. Umehluko phakathi kokufundwa yinzwa yomunwe nenani elibaliwe legazi lomthambo ophuma enhliziyweni, ovame ukuba ngaphezu kwamaphuzu angu-5 amaphesenti, ubizwa ngokuthi igebe lokugcwala komoya-mpilo, futhi uyinkomba, hhayi ukuhlonza okuqinisekisiwe.

Ukuqinisekisa kudinga i-co-oximetry esebenzisa ubude bamaza amaningi esampuleni yegazi, ekala i-methemoglobin ngokuqondile. Igazi elinsundu njengoshokoledi elingakhanyi lapho lifakwa umoya-mpilo nalo liyinkomba efanayo. Noma yisiphi isinqumo sokwelapha i-methemoglobinemia siqala ngalokho kulinganisa kanye nezimpawu, hhayi nge-pulse oximeter kuphela.

Indlela ukwelashwa okuqashwe ochwepheshe okuchazwe ngayo kulebula

Lesi sigaba sichaza umjovo onikezwa ochwepheshe bezokwelapha ngencwadi kadokotela. Asisona isiqondiso sokuwusebenzisa ngomlomo, futhi akukho kulokhu okusebenza kumaconsi noma kumaphilisi angama-capsule athengiselwa abathengi.

Ulwazi lwamanje lokunqunywa komjovo we-methylene blue luchaza ukwelashwa kwe-methemoglobinemia engatholakali ngokuzalwa kubantu abadala nasezinganeni njengokunikeza u-1 mg nge-kg ngomthambo phakathi kwemizuzu engu-5 kuya ku-30. Ngomkhiqizo ojwayelekile ongu-5 mg nge-mL, lokho kulingana no-0.2 mL nge-kg. Uma i-methemoglobin ihlala ingaphezu kwamaphesenti angu-30 noma izimpawu ziqhubeka ngemva kwehora elilodwa, kungalandela umthamo wesibili ongu-1 mg nge-kg. Uma imithamo emibili ingayixazululi inkinga, ilebula iyalela ochwepheshe bezokwelapha ukuba basebenzise enye indlela yokwelapha kunomthamo wesithathu.

Imininingwane yokunikeza umjovo ibalulekile. Ishubhu kufanele libe elingena emthanjeni futhi lisebenze kahle; akufanele kube umjovo ongaphansi kwesikhumba. Uketshezi lungahlanjululwa ku-50 mL we-dextrose engamaphesenti angu-5 ukuze kwehliswe ubuhlungu endaweni yomjovo, ikakhulukazi ezinganeni, bese lusetshenziswa ngokushesha. Akufanele luhlanjululwe ngezixazululo ze-sodium chloride, ngoba i-chloride yehlisa ikhono likadayi lokuncibilika. Izingxenye ezingasetshenzisiwe ziyalahlwa futhi uketshezi luyahlolwa ngaphambi kokusetshenziswa.

Izixwayiso ezintathu ziqondisa zonke izinqumo zasesibhedlela. Isixwayiso esisebhokisini sikhuluma nge-serotonin syndrome, engabulala lapho i-methylene blue ihlangana nemithi esebenza ku-serotonin, kuhlanganise nama-SSRI, ama-SNRI, ama-MAO inhibitor, amanye ama-opioid, ne-dextromethorphan. Iziguli zitshelwa ukuthi zingayiphuzi imithi enjalo amahora angu-72 ngemva komthamo wokugcina, futhi lapho le nhlanganisela ingenakugwenywa, ilebula ifuna umthamo ophansi kakhulu ongase usetshenziswe, kanye nokuqashwa ngokucophelela. Ukusebenzisana okuhlobene ne-serotonin kuxoxwa ngakho ekusebenzisaneni kwe-methylene blue neminye imithi kanye ne-serotonin syndrome. I-hemolysis iyisixwayiso sesibili: ukuhlakazeka kwamangqamuzana abomvu egazi okunama-Heinz body, ukukhuphuka kwe-bilirubin engaqondile, ukwehla kwe-haptoglobin, ne-anemia engavela ngemva kosuku noma kamuva futhi engase idinge ukumpontshelwa igazi. Esesithathu ukulahleka komphumela noma ukubuya kwesimo, okubonwa lapho umuntu echayeke ku-dapsone noma ezintweni zohlobo lwe-aniline, nalapho kukhona ukushoda kwe-G6PD, lapho ilebula iphinde iqondise kwenye indlela yokwelapha. Ukungasebenzi kahle kwezinso akuvimbeli ukusetshenziswa, kodwa uma kuphakathi nendawo noma kubi kakhulu, ukwelashwa kunqunyelwa emthamo owodwa ongu-1 mg nge-kg. Izehlakalo ezingathandeki kudatha yabantu abadala esetshenziswe kulebula zihlanganisa ikhanda elibuhlungu, isicanucanu, isifo sohudo, amazinga aphansi e-potassium ne-magnesium, ukunyakaza kwemisipha ngokuzuma, nezehlakalo ezifana nokuquleka, kube nesehlakalo esisodwa esibi esifana nokuquleka ezigulini ezingu-31. Udayi ubuye wehlise ngokungelona iqiniso amanani afundwa yi-pulse oximeter ngemva kokufakwa ngomthambo, ngakho ochwepheshe bezokwelapha balandela i-co-oximetry nezimpawu esikhundleni salokho.

Ukunakekelwa okusekelayo kuqhubeka kanye nalokhu: umoya-mpilo ogeleza kakhulu, ukusekelwa kwendlela yomoya nokujikeleza kwegazi, ukulungiswa kwezinga le-glucose, nokuqashwa. Izimo ezincane ezingenazimpawu zingaphela lapho into eyimbangela isusiwe. Imingcele evame ukucashunwa iqala ukwelapha iziguli ezinezimpawu cishe kumaphesenti angu-20, noma kumaphesenti angu-10 kuya ku-20 lapho ukufika komoya-mpilo ezicutshini sekuphazamisekile, futhi icabangela ukwelapha iziguli ezingenazimpawu kusukela cishe kumaphesenti angu-30. Izimpawu ezinzima zelashwa ngaphandle kokulinda inani laselabhorethri. I-ascorbic acid, ukumpontshelwa igazi ngokushintshanisa, nomoya-mpilo ongaphansi kwengcindezi ephakeme kuyizindlela zokusindisa lapho i-methylene blue ingenakusetshenziswa noma ingasebenzi, kodwa i-ascorbic acid isebenza kancane kakhulu. Imibhalo yokuqinisekisa ubumsulwa banoma yimuphi umkhiqizo ojovwayo ingumbuzo ohlukile wokukhiqiza, ochazwe endleleni yokufunda isitifiketi sokuhlaziywa kwe-methylene blue.

I-benzocaine nombuzo ngejeli lokuqhamuka kwamazinyo

Ingxenye enkulu yokusesha kwabathengi ivela kubazali abasebenzise ijeli noma isifutho se-benzocaine emlonyeni bese bebona izindebe eziluhlaza okwesibhakabhaka noma inani eliphansi ku-oximeter. Izigaba ezintathu kufanele zigcinwe zihlukene.

Ukusola ukuchayeka yisigaba sasekhaya. I-benzocaine yaziwa njengento eyimbangela eyenza i-oxidation, futhi abalawuli baxwayise ngokuthi imikhiqizo ye-benzocaine yomlomo etholakala ngaphandle kwencwadi kadokotela akufanele isetshenziselwe ukuqhamuka kwamazinyo noma ezinganeni ezingaphansi kweminyaka engu-2, ngoba i-methemoglobinemia ehlobene ne-benzocaine ingaba nzima futhi inzuzo yayo ebuhlungwini bokuqhamuka kwamazinyo incane. Yeka umkhiqizo, bhala isikhathi nenani elisetshenzisiwe, qaphela izimpawu ezifana nokuphaphatheka okungajwayelekile, umbala ompunga noma oluhlaza okwesibhakabhaka wezindebe nezindawo ezingaphansi kwezinzipho, ukuphelelwa umoya, ukozela okungajwayelekile, noma ukungadli kahle, bese ufuna ukuhlolwa okuphuthumayo ngokushesha. Ungayinikezi i-methylene blue ekhaya nganoma yiluphi uhlobo. Awukho umthamo wasekhaya futhi akukho ukuhlola kwasekhaya okungaqinisekisa ukuthi lesi simo asikho.

Ukuhlonza yisigaba sasesibhedlela. Ochwepheshe bezokwelapha baqinisekisa nge-co-oximetry, babukeze konke ukuchayeka ezintweni ezenza i-oxidation kuhlanganise i-dapsone, ama-nitrite, nezinhlanganisela ze-aniline, bese behlola izimpawu nokufika komoya-mpilo ezicutshini kunokubheka inani elilodwa lodwa.

Ukwelashwa okuqashwe ochwepheshe yisigaba sasewadini esichazwe ngenhla. Ukuthi i-benzocaine yiyona ebangele lesi simo akulishintshi ithebula lemithamo. Ilebula yamanje yomjovo ayiyisho ngokuqondile i-benzocaine; isimo esibangelwe yi-benzocaine singena ngaphansi kwe-methemoglobinemia engatholakali ngokuzalwa futhi siphathwa ngenqubo efanayo eqashwe ochwepheshe, kuhlanganise nokuhlola i-G6PD, izinso, ne-serotonin.

Lapho i-methylene blue ingeyona impendulo

Ayiyona impendulo lapho kwaziwa ukuthi kukhona ukushoda kwe-G6PD. Ayiyona impendulo ngemva kokuba imithamo emibili eshiwo kulebula ingasebenzanga noma lapho i-methemoglobinemia ibuya, okuyinkomba yokuqhubeka nokumuncwa kwemithi efana ne-dapsone. Ayiyona impendulo njengendlela yokuvimbela, njengendlela yokusebenzisa njalo izithasiselo, noma njengekhambi lasekhaya ngemva kokuchayeka kumakhemikhali. Umthamo ophezulu noma ukusetshenziswa okuphindwayo kungalinyusa lona kanye inani okuhloswe ukulehlisa, futhi i-hemolysis ingabonakala ngemva kosuku lapho isiguli sesisekhaya. Leyo ngozi evela sekudlule isikhathi ingesinye sezizathu ezenza izibhedlela ziqaphe isiguli kunokusidedela ngokushesha.

Isifinyezo esithembekile sifushane. I-methemoglobinemia ihilela i-ayoni esidlule ku-oxidation engakwazi ukuthwala umoya-mpilo. I-methylene blue iyisithuthi sama-electron esivumela amangqamuzana abomvu egazi ukuba anikeze leyo ayoni ama-electron, inqobo nje uma ingqamuzana lingakwazi ukwenza i-NADPH futhi umthamo uhlala ngaphakathi kohlelo olulinganiselwe olushiwo kulebula. Ukuhlonza kudinga i-co-oximetry ngoba imishini elula yokuqapha iyadukisa. Konke okunye, kusukela ku-dextrose yokuhlanjulula kuya emlandweni wemithi ethinta i-serotonin nasethubhini le-benzocaine elisekhabetheni lemithi, kuyimininingwane esekela leso sithuthi esisodwa.