Imethylene blue kwimethemoglobinemia: kutheni isetyenziswa ezibhedlele

Isigulana sifika sinemilebe engwevu njengelitye lesileyiti, siphefumla ngokukhawuleza, siphendula kancinci. Isixhobo sokubeka iliso sibonisa ukuba ukuzaliswa kwegazi yioksijini ngama-85 epesenti. Umongikazi unyusa ioksijini. Inani alitshintshi. Kutsalwa igazi, liphuma limdaka njengetshokholethi, kwaye lihlala limdaka naxa libekwa emoyeni. Olu landelelwano luphawu oluqhelekileyo olukhokelela kunyango lwemethemoglobinemia ngemethylene blue, kwaye lubonisa ukuba kutheni le meko ibhidanisa iintsapho nezixhobo ngokufanayo.

Ingxaki ayikho emiphungeni. Ikwi-iron engaphakathi kwihemoglobin.

Iimo ezimbini zeathom enye ye-iron

Imolekyuli nganye yehemoglobin ithwala i-iron ekwimo ye-ferrous, ebhalwa njenge-Fe2+. Kule mo ibophelela ioksijini emiphungeni ize iyikhulule kwizicwili. Iikhemikhali ezibangela i-oxidation zinokususa enye i-electron kule iron, ziyiguqulele kwimo ye-ferric, i-Fe3+. Into enombala evelayo yimethemoglobin. I-iron ekwimo ye-ferric ayikwazi ukubophelela ioksijini, kwaye okubi ngakumbi kukuba yenza iindawo eziseleyo ze-ferrous kwaloo molekyuli zibambelele ngokuqinileyo ngakumbi kwioksijini yazo, ukuze kukhululwe ioksijini encinane apho ifuneka khona.

Igazi elisempilweni ligcina imethemoglobin ingaphantsi malunga ne-1 epesenti ngenxa yokuba i-enzayim yokulungisa isebenza rhoqo. Indlela ephambili yokulungisa isebenzisa i-NADH ne-cytochrome b5 reductase, ixhaswa yi-glycolysis eqhelekileyo kwiseli ebomvu yegazi. Indlela encedisayo isebenzisa i-NADPH, kodwa kwiimeko eziqhelekileyo yenza umsebenzi omncinane. Iimpawu zihambelana ngokusondeleyo nepesenti, nangona ianemia okanye isifo sentliziyo nemiphunga zinokwenza inani elisezantsi libe yingozi. Amanani akufutshane ne-10 ukuya kuma-20 epesenti anokubangela icyanosis ebonakalayo nokudinwa. Amanani angaphezu kwama-30 epesenti adla ngokubangela intloko ebuhlungu, ukuphelelwa ngumoya, nokubhideka. Amanani akufutshane nama-70 epesenti adla ngokubulala. La manani ziindidi zoluhlu, hayi iziqinisekiso, kuba okubalulekileyo kukufikiswa kweoksijini, hayi ixabiso laselabhoratri lodwa.

Izinto eziqhelekileyo ezibangela le meko ifunyenweyo ziquka idapsone, iinitrite neenitrate, iikhompawundi zeaniline, namayeza okubulala iintlungu kwindawo ethile afana nebenzocaine neprilocaine. Kukho ukunqongophala kwee-enzayim umntu azalwa nako, kodwa kunqabile. Uninzi lweemeko ezibonwa ezibhedlele zezifumaneka kamva, nto leyo ethetha ukuba inyathelo lokuqala lonyango lisoloko likukuyekisa ukuchanabeka kwinto ebangela ingxaki.

Umthuthi wee-electron osetyenziswa zizibhedlele

Imethylene blue ayiniki ioksijini. Inika indlela yokuthutha ii-electron. Ngaphakathi kwiseli ebomvu yegazi, i-enzayim isebenzisa i-NADPH ukuguqula idayi eluhlaza okwesibhakabhaka ibe yimo yayo engenambala, ileucomethylene blue, ngokuyinika ii-electron. Loo mo ingenambala ke inika ii-electron kwi-iron ekwimo ye-ferric ngaphandle koncedo lwe-enzayim, ibuyisele ihemoglobin kwimo ye-ferrous, ize ibuyele kwimo eluhlaza okwesibhakabhaka. Idayi iyawuphinda lo mjikelo. Olu dluliselo luchazwa kwindlela imethylene blue ehambisa ngayo ii-electron phakathi kwabanikeli nabamkeli, kwaye imo engenambala efumene ii-electron ichazwa kuthelekiso lwemethylene blue neleucomethylene blue.

Le ndlela yokusebenza ichaza imida emibini ebothusayo abantu abaqala ukufunda ngalo mba. Okokuqala, lo mthuthi ufuna i-NADPH, kwaye i-NADPH yeeseli ezibomvu zegazi ixhomekeke kwi-glucose-6-phosphate dehydrogenase, i-G6PD. Xa kukho ukunqongophala kwe-G6PD, idayi isenokungaguqukeli kwimo yayo esebenzayo ngoxa yona ngokwayo isongeza uxinzelelo lwe-oxidation, yiyo loo nto ileyibhile yemveliso esetyenziswa esibhedlele ichaza ukunqongophala kwe-G6PD njengesizathu sokungayisebenzisi. Okwesibini, imethylene blue ngokwayo ibangela i-oxidation xa iyonke yeedosi iphezulu. Xa iyonke idlula malunga ne-7 mg nge-kg, okanye ngamanye amaxesha ngaphantsi koko xa iidosi ziphindwa, inokunyusa imethemoglobin ize itshabalalise iiseli ezibomvu zegazi endaweni yokuzilungisa. Idayi eninzi ayithethi ukuhlangulwa okungakumbi. Uluhlu lwedosi luvunyelwe ukuba lube mxinwa ngabom.

Kutheni uvavanyo olubonakala lulula lulahlekisa

Iintsapho zidla ngokukhangela uvavanyo lwemethylene blue ezinokulwenza ekhaya. Alukho uvavanyo olunjalo. Eli binzana lidla ngokubhekisela kwinkqubo yoxilongo xa kurhanelwa imethemoglobinemia, kwaye loo nkqubo imele yenziwe elabhoratri.

Izixhobo eziqhelekileyo zokulinganisa ioksijini ngepulse zifunda kuphela ubude bamaza bokukhanya obubini. Njengoko imethemoglobin inyuka, ukufunxwa kokukhanya kwezo ntlobo zimbini zamaza kuyasondelana, kwaye ukuzaliswa yioksijini okubonisiweyo kusondela malunga nama-85 epesenti nokuba imeko yokwenene injani. Ioksijini eyongezelelekileyo ayililungisi elo nani kuba isivamvo asilinganisi eyona nto ingalunganga. Uxinzelelo lweoksijini egazini lemithambo ephuma entliziyweni, i-PaO2, lunokubonakala luqhelekile kwangaxeshanye, kuba lulinganisa ioksijini enyibilikileyo kwiplasma kunokuba lulinganise ioksijini ethwalwa yihemoglobin. Ngoko isixhobo sokuhlalutya iigesi zegazi esibala ukuzaliswa yioksijini sisuka kwi-PaO2 sinokunika inani elithomalalisa inkxalabo ngoxa isigulana sisene-cyanosis. Umahluko phakathi kwesivamvo esisemnweni nexabiso elibaliweyo legazi lemithambo ephuma entliziyweni, odla ngokudlula amanqaku epesenti ama-5, ubizwa ngokuba ngumsantsa wokuzaliswa yioksijini, kwaye luphawu oluncedayo, hayi uxilongo.

Ukuqinisekisa kufuna i-co-oximetry esebenzisa ubude bamaza obuninzi kwisampulu yegazi, elinganisa imethemoglobin ngqo. Igazi elimdaka njengetshokholethi elingakhanyiyo xa linikwa ioksijini nalo libonisa loo meko. Nasiphi na isigqibo sonyango lwemethemoglobinemia siqala ngalo mlinganiselo kunye neempawu, asiqali ngesixhobo sokulinganisa ioksijini ngepulse sodwa.

Oko kuchazwa yileyibhile ngonyango oluphantsi kolawulo

Eli candelo lichaza inaliti efuna umyalelo kagqirha enikwa ngabasebenzi bezonyango. Ayisosikhokelo sokuyithatha ngomlomo, kwaye akukho nanye kwezi nkcukacha esebenza kumathontsi okanye kwiikhapsuli ezithengiselwa ukusetyenziswa ngabathengi.

Ulwazi lwangoku lokumisela imethylene blue enikwa ngenaliti luchaza unyango lwemethemoglobinemia efunyenweyo kubantu abadala nakubantwana njenge-1 mg nge-kg enikwa emthanjeni kwimizuzu emi-5 ukuya kwengama-30. Kwimveliso eqhelekileyo ene-5 mg nge-mL, oko kulingana ne-0.2 mL nge-kg. Ukuba imethemoglobin ihlala ingaphezu kwama-30 epesenti okanye iimpawu ziyaqhubeka emva kweyure enye, kunokulandelwa ngedosi yesibini ye-1 mg nge-kg. Ukuba iidosi ezimbini aziyisombululi ingxaki, ileyibhile iyalela abasebenzi bezonyango ukuba basebenzise olunye unyango kunokunika idosi yesithathu.

Iinkcukacha zokunikezelwa zibalulekile. Umbhobho kufuneka ube ngowokunika iyeza emthanjeni osebenza kakuhle; akufuneki linikwe ngenaliti phantsi kolusu. Isisombululo sinokuxutywa kwi-50 mL yedextrose ye-5 epesenti ukunciphisa iintlungu kwindawo yenaliti, ingakumbi ebantwaneni, size sisetyenziswe ngokukhawuleza. Akufuneki sixutywe kwizisombululo zesodium chloride, kuba ichloride inciphisa ukunyibilika kwedayi. Iinxalenye ezingasetyenziswanga ziyalahlwa, kwaye isisombululo siyahlolwa ngaphambi kokusetyenziswa.

Izilumkiso ezintathu ziphembelela zonke izigqibo zasesibhedlele. Isilumkiso esikwibhokisi sithetha ngeserotonin syndrome, enokubulala xa imethylene blue idibana namayeza achaphazela iserotonin, kuquka ii-SSRI, ii-SNRI, izithinteli ze-MAO, ezinye ii-opioid, nedextromethorphan. Izigulana zixelelwa ukuba zingawathathi loo mayeza iiyure ezingama-72 emva kwedosi yokugqibela, kwaye xa ukusetyenziswa kunye kungenakuphetshwa, ileyibhile ifuna eyona dosi iphantsi enokwenzeka kunye nokuqwalaselwa ngokusondeleyo. Unxibelelwano oluchaphazela iserotonin luchazwa kunxibelelwano lwemethylene blue namanye amayeza nakwiserotonin syndrome. Ihemolysis sisilumkiso sesibini: kukuqhekeka kweeseli ezibomvu zegazi okunemizimba ye-Heinz, ukunyuka kwebilirubin engathanga ngqo, ukwehla kwehaptoglobin, kunye neanemia enokuvela emva kosuku okanye kamva nenokufuna ukutofelwa igazi. Esesithathu kukulahleka kwesiphumo okanye ukubuya kwemeko, okubonwa emva kokuchanabeka kwidapsone okanye kwizinto zohlobo lweaniline, nakukunqongophala kwe-G6PD, apho ileyibhile iphinda yalathise kolunye unyango. Ukungasebenzi kakuhle kwezintso akuthinteli ukusetyenziswa, kodwa xa kuphakathi okanye kunzima, unyango lulinganiselwa kwidosi enye ye-1 mg nge-kg. Iziganeko ezingathandekiyo kwidatha yabantu abadala ekwileyibhile zaziquka intloko ebuhlungu, isicaphucaphu, urhudo, ipotassium nemagnesium ephantsi, ukuxhuzula kwezihlunu, neziganeko ezifana nokuxhuzula komzimba, kukho isiganeko esinye esinzulu esifana nokuxhuzula komzimba phakathi kwezigulana ezingama-31. Idayi ikwabangela ukuba isixhobo sokulinganisa ioksijini ngepulse sibonise amanani aphantsi angachanekanga emva kokufakwa kwayo emthanjeni, ngoko abasebenzi bezonyango balandela i-co-oximetry neempawu endaweni yoko.

Unonophelo oluxhasayo luqhubeka ngaxeshanye: ioksijini ehamba ngesantya esiphezulu, ukuxhasa indlela yomoya nokujikeleza kwegazi, ukulungisa iglucose, nokuqwalasela isigulana. Iimeko ezingathathi ntweni nezingenazo iimpawu zinokuphela xa into ezibangeleyo isusiwe. Imida edla ngokukhankanywa isebenzisa unyango kwizigulana ezineempawu ukusuka malunga nama-20 epesenti, okanye ukusuka kwi-10 ukuya kuma-20 epesenti xa ukufikiswa kweoksijini sele kuphazamisekile, kwaye iqwalasela unyango kwizigulana ezingenazo iimpawu ukusuka malunga nama-30 epesenti. Iimpawu ezinzima zinyangwa kungalindwanga inani laselabhoratri. Iascorbic acid, ukutshintshwa kwegazi ngokutofelwa, kunye neoksijini ephantsi koxinzelelo oluphezulu ziindlela zokuhlangula xa imethylene blue ingenakusetyenziswa okanye ingasebenzi, kodwa iascorbic acid isebenza kancinci kakhulu. Amaxwebhu angobunyulu bayo nayiphi na imveliso etofwayo ngumcimbi owahlukileyo wokuvelisa, ochazwa kwindlela yokufunda isatifikethi sohlalutyo lwemethylene blue.

Ibenzocaine nombuzo wejeli yokuphuma kwamazinyo

Inxalenye enkulu yokukhangela kwabathengi ivela kubazali abasebenzise ijeli okanye isitshizi sebenzocaine emlonyeni baze babone imilebe eluhlaza okwesibhakabhaka okanye inani elisezantsi kwisixhobo sokulinganisa ioksijini. Kufuneka kwahlulwe izigaba ezintathu.

Ukuchanabeka okurhanelwayo sisigaba sasekhaya. Ibenzocaine yaziwa njengento enokubangela i-oxidation, kwaye amagunya olawulo alumkisile ukuba iimveliso zebenzocaine ezisetyenziswa emlonyeni nezithengwa ngaphandle komyalelo kagqirha akufanele zisetyenziswe ekuphumeni kwamazinyo okanye kubantwana abangaphantsi kweminyaka emi-2, kuba imethemoglobinemia enxulumene nebenzocaine inokuba nzima kwaye uncedo lwayo kwiintlungu zokuphuma kwamazinyo luncinane. Yeka ukusebenzisa imveliso, bhala ixesha nobungakanani obusetyenzisiweyo, qaphela iimpawu ezifana nokuba luthuthu ngokungaqhelekanga, umbala ongwevu okanye oluhlaza okwesibhakabhaka wemilebe nezicwili ezingaphantsi kweenzipho, ukuphelelwa ngumoya, ukozela okungaqhelekanga, okanye ukungondleki kakuhle, uze ufune uvavanyo olungxamisekileyo ngokukhawuleza. Musa ukunika imethylene blue ekhaya nangayiphi na indlela. Akukho dosi yasekhaya, kwaye akukho vavanyo lwasekhaya olunokukhupha amathuba okuba le meko ikhona.

Uxilongo sisigaba sasesibhedlele. Abasebenzi bezonyango baqinisekisa nge-co-oximetry, baphonononge konke ukuchanabeka kwizinto ezibangela i-oxidation, kuquka idapsone, iinitrite, neekhompawundi zeaniline, baze bavavanye iimpawu nokufikiswa kweoksijini kunokuba bajonge inani elinye lodwa.

Unyango oluphantsi kolawulo sisigaba sewadi esichazwe ngasentla. Nokuba ibenzocaine ibingunobangela, oko akuyitshintshi itheyibhile yeedosi. Ileyibhile yangoku yenaliti ayiyikhankanyi ibenzocaine ngokukodwa; imeko ebangelwe yibenzocaine iwela phantsi kwemethemoglobinemia efunyenweyo kwaye ilawulwa ngenkqubo efanayo ephantsi kolawulo, kuquka ukuhlolwa kwe-G6PD, kwezintso, nokweserotonin.

Xa imethylene blue ingesosisombululo

Ayisosombululo xa kusaziwa ukuba kukho ukunqongophala kwe-G6PD. Ayisosombululo emva kokuba iidosi ezimbini ezichazwe kwileyibhile zingasebenzanga okanye xa imethemoglobinemia ibuya, nto leyo ebonisa ukuqhubeka kokufunxwa kwamayeza afana nedapsone. Ayisosombululo sokuthintela, sokusetyenziswa rhoqo njengesongezelelo, okanye njengeyeza lasekhaya emva kokuchanabeka kwikhemikhali. Idosi ephezulu okanye ukusetyenziswa okuphindaphindiweyo kunokunyusa kanye elo nani ekufanele lilehlise, kwaye ihemolysis inokuzibonakalisa emva kosuku xa isigulana sele sisekhaya. Loo mngcipheko ulibazisekileyo sesinye sezizathu zokuba izibhedlele ziqwalasele isigulana kunokuba zisikhuphe ngokukhawuleza.

Isishwankathelo esinyanisekileyo sifutshane. Imethemoglobinemia yimeko apho i-iron efumene i-oxidation ingakwazi ukuthwala ioksijini. Imethylene blue ngumthuthi wee-electron ovumela iiseli ezibomvu zegazi ukuba zibuyisele loo iron kwimo efumene ii-electron, ukuba iseli inako ukwenza i-NADPH kwaye idosi ihlala ngaphakathi koluhlu olumxinwa lonyango oluchazwe kwileyibhile. Uxilongo lufuna i-co-oximetry kuba izixhobo ezilula zokubeka iliso ziyalahlekisa. Yonke enye into, ukusuka kwidextrose yokuxuba ukuya kwimbali yamayeza achaphazela iserotonin nakwityhubhu yebenzocaine ekwikhabhathi yamayeza, ziinkcukacha ezixhasa loo mthuthi mnye.