【持续性肾脏替代治疗crrt英文精品课件】respiratory compensation in metabolic acidosis

Metabolicacidosis Metabolicacidosis aprimarydecreaseinserumHCO3HCO3alsolowinrespiratoryalkalosisMetabolicacidosiswithoutalowserumpHcanoccurifthereisanotheracid basedisturbancethatincreasestheserumHCO3e g metabolicalkalosisfromvomiting RenalcontrolofserumpH SerumpHismaintainedinatightrangevialungcontrolofpCO2andrenalcontrolofHCO3ThekidneyscontrolHCO3by1 reabsorbingallfilteredHCO3 about4000mEq day defectin proximalRTA2 excretingacidproducedfromdiet about70meq day primarilyasNH4 andHPO4 defectin distalRTA Respiratorycompensationinmetabolicacidosis ThechangeinpCO2is1 2timesthechangeinHCO3oralternativelyputathumboverthe7inthepHIfisadequaterespiratorycompensationissimplemetabolicacidosisIfinadequaterespiratorycompensationisamixeddisorder combinedmetabolicandrespiratoryacidosis AnionGap Na Cl HCO3 12 4meq LOutsideofUSAmostcountriesexcludetheK Anotherwayofthinkingofthisformulaisasunmeasuredanions unmeasuredcationsUnmeasuredanions mostlyalbumin phosphorous andsulfateForeach1gmdecreaseinserumalbumintheexpectedaniongapwouldgodownby2 3Unmeasuredcations Mg Ca paraproteins Aniongap AG interpretation Normalinitiallydescribedas12 4butwithnewionselectiveelectrodesnormalinsomehospitalssignificantlylowerAninsensitivescreenformildtomoderatedeviationsfromnormalPronouncedelevations e g 30 theidentityoftheanionisusuallyobviousLesspronouncedelevations theunmeasuredanionsidentityoftennotclear deltaHC03 deltaAGratio Typicallyisa1 1ratiobetweenincreaseinaniongapandadecreaseinHCO3IfthechangeinHCO3exceedsthechangeinaniongapby3mEq LthissuggeststhatbothahighandnormalaniongapacidosisarepresentIfthechangeinaniongapismorethanthechangeinHCO3probablybothametabolicacidosisandmetabolicalkalosisarepresentConversionofhighaniongaptonormalaniongapcanoccurifpatientexcretestheanionfromtheacidbutretainstheH HighAGmetabolicacidosis Glycols ethyleneandpropyleneOxoproline pyroglutamicacidL lacticacidD lacticacidMethanol formicacidAspirin multipleorganicacidsRenalfailure multipleorganicandinorganicacidsKetoacidosis B OHbutyricandacetoacidicacids Hyperlactatemia ElevatedserumlactatewithoutacidosisNormallactatelevelincriticalcarepatient 2mm LMinorelevations aslowas0 75mm L correlatewithmortalityinpatientsinER ICU orwithsepsisLactate basedtherapiesinRxofsepsis LacticAcid Lacticacidcanexistintwoforms L lactateandD lactate Inmammals onlyL lactateisaproductofmetabolism ThelabmeasuresonlyL lactateNormaldailyproductionoflactate15to30mmol kgperdayAllofthislacticacidisconvertedtoCO2andwaterwithnonetacid baseeffect TypeAlacticacidosis Mechanism overproductionoflacticacidduetoshock hypoxemia profoundanemia carbonmonoxide seizures transient Anaerobicglycolysisof1moleofglucosegeneratesATPbutonlyabout10 ofthatgeneratedwithaerobicglycolysisWithmarkedanoxiabodycangenerate12mm minoflacticacidor12meq minofH Anaerobiclactatemetabolism Glucoseentersglycolyticcycleincytoplasmtoformpyruvate Sinceno02foroxidativephosphorylationpyruvatecannotenterthemitochondriatogenerateATPbutisconvertedtolactateLactategeneratedinmusclegoestoliverwhichconvertsittoglucosewhichcanbecycledbacktomuscle Coricycle TypeBlacticacidosis Mechanism notduetooverproductionoflacticacidbutusuallyduetodecreasedliverutilizationfromgeneticdefects drugs vitamindeficiencies toxinsIncomparisontotypeA muchlesscommon insomecasesduetoageneticdefectonlymanifestedbyadrugortoxin theacidosisnotassevere sinceacidosisnotasseveremaybeeasiertotreatwithHCO3Causes congenitaldefectsinglucoseandlactatemetabolismespeciallyingeneticmitochondrialdiseases liverdisease diabetes neoplasms vitamindeficiencies toxins drugs Drugsassociatedwithlacticacidosis highlyactiveretroviralagentsethyleneglycol methanol propyleneglycolsalicylatemetformin phenforminclenbuterol beta blockercontaminantinheroinlinezolidpropofol propofolinfusionsyndromepropyleneglycolsolvent lorazepamnitroprusside cyanideformation Metforminandlacticacidosis Packageinsert donotgiveifcreatinine 1 4infemaleor 1 5inmalePrecipitatedbyworseningofCKDviaNSAIDs ACEinhibitors orcontrastODortherapeuticdosageReportsof30 50 mortalityCRRTcanremovethemetforminandalsohelpcorrectthelacticacidosis Metformin inducedlacticacidosis MALA recentarticletitles Doesmetforminincreaseriskoffatalornonfatallacticacidosis Metforminassociatedlacticacidosis isitreallyjustanassociation Metformin potentialbenefitsanduseinchronickidneydiseaseMetformindoesnotincreaseriskforlacticacidosisintype2diabetesmellitus D Lacticacidosis CertainbacteriaintheGItractmayconvertcarbohydrate cellulose intoorganicacids primarilyD lacticacidwhichwhenabsorbedisveryslowlymetabolizedMostpatientswhodevelopD lacticacidosishaveslowGItransitaswithblindloops obstruction drugsdecreasingGImotilityOftenexacerbatedbyincreasedcarbohydrateintakeorantibioticsallowingforovergrowthoflactobacilliCNSfindings usuallyisassociatedwithconfusion dysarthria ataxia duetoothertoxinsmadebythebacteria D lactateisnotmeasuredwhenorderlacticacidlevelTreatment restrictcarbohydrates hydrate givebicarbonate MELAS Mitochondrialencephalopathy lacticacidosis stroke likeepisodesUsuallypresentswithseizuresAlmostalwaysdiagnosedinchildhoodDiagnosisusuallymadebymoleculargenetictestingofmitochondrialDNAAdults casereports suspectifseizuresworsenedbyvalproicacid Alcoholicketosis Usuallyahistoryoflong termalcoholuse reducedfoodintake nauseaandvomitingStarvationketosis similarbutlesssevereKetonemeasurementmaybenormalsincebetahydroxybutyricacidmaybe90 ofacidpresentIncreasedincidenceofsuddendeathTreatment glucose increasesinsulin normalsalinetocorrectvolumeloss thiaminetopreventWernicke sencephalopathy donotneedtogiveHCO3sinceastheabnormalitycorrectstheketoacidsareconvertedtoHCO3 Pyroglutamicacidosis ConsiderifunexplainedAGacidosisandacetaminopheningestion eitherODortherapeuticdoseSomestudieshavefoundahighincidenceofthisifunexplainedAGacidosisandCNSchangesGlutathionelevelsreducedduetotheoxidativestressofanacuteillnessandsuppressionfromacetaminophenReducedglutathionelevelsleadtoincreasedpyroglutamicacidlevels oxoproline OsmolarGap SerumOsm 2 Na BUN 2 8 glc 18CalculatedanddeterminedOsmshouldagreewithin10to15mOsm kg Ifnot thenserumNamaybespuriouslylowORosmolytesotherthenNa glcorureahaveaccumulated Theosmolargapisareliableandhelpfultoolwhenscreeningfortoxin associatedhighAGacidosisMustcorrectforETOHifpresent Etyleneglycolandmethanolmetabolism ThemajortoxicitiesoftheseagentsarenotfromtheagentsthemselvesbutfrommetabolitesMethanolproducesformicacid formaldehydeandethyleneglycolproducesglycolicacidBotharemetabolizedbyalcoholdehydrogenasesoifthepatienthasconsumedETOHthiswouldslowformationofthelethalmetabolitesAlcoholdehydrogenasemuchmoreavidlybindstoETOHthantomethanolorethyleneglycolFomepizole alcoholdehydrogenasespecificinhibitor muchmoreeffectivethanETOH Ethyleneglycolpoisoning Suicideattempt substituteforalcohol homicidalantifreeze3 phaseclinicalpicture1 4 12hrs CNS GIphase inebriation mimicsEtOHintoxication2 12 24hrs worseacidosis cardiopulmonarydysfunction increasedHR increasedBP myocarditis pneumonia pulmonaryedema myositis3 36 72hrs oliguricrenalfailureCluesforthisdiagnosis crystalsintheurine duetocalciumoxalateformationfromtheethyleneglycol MWofethyleneglycol 46soalevelof20mg dlwouldincreaseAGby4andalevelof100by16 Methanolpoisoning MethylalcoholorwoodalcoholCanbefrombootlegalcoholunknowinglycontaminatedAsathinnerforshellacandvarnish windscreenandgasolineantifreeze fuelforalcoholburningdevicesNosymptomsforthefirst12hours1ouncecanproduceabloodlevelof100mg dLToxicityprimarilyCNSandopticnervedamageMolecularweightis32soalevelof20mg dlproducesanAGof6and100anAGof31 CrtieriaforRxinmethanolorethyleneglycolpoisoning plasmaconcentration 20mg dlORdocumentedrecenthistoryofingestionoftoxicamountsandosmolalgap 10ORatleast3ofthefollowing arterialpH10 oxalatecrystalluria withethyleneglycol Unexplainedaniongap NEJM2009 2216 Hemodialysisformethanolorethyleneglycol Goal topreventendorgantoxicityMechansim correctsmetabolicabnormalitiesandeliminatesnonmetabolizedmethanolorEGIndications level 50mg dL HCO3 15orpH 7 3 opticinjuryfrommethanol PropyleneGlycolToxicity AnalcoholusedtoenhancewatersolubilityofmanyhydrophobicIVmedications lorazepam diazepam esmolol nitroglycerin Propyleneglycoltoxicityfromsolventaccumulationhasbeenreportedin19 66 ofICUpatientsreceivinghighdoselorazepamordiazepam 2days Signsoftoxicity agitation coma seizures tachycardia hypotension Salicylateintoxication RespiratoryalkalosisusuallyaccompaniesASAintoxication butmetabolicacidosismaybeprominentinchildrenThetoxicityisprimarilydue ASA intissuesTheunchargedformHASAcrossescellmembraneseasilysoaprimarygoalistopreventmetabolicacidosissincewouldincreaseconversionofASAtoHASA ASAintoxicationRx ReductionofHASAmovementintocells especiallybraincells NaHCO3ExcretionofASAinurinebyalkalination NaHCO3 acetazolamide butcompeteswithproteinbindingofASAandmayincreasefreelevels ifnotcarefullymonitoredcancausemetabolicalkalosis Hemodialysis consider ASA 60mg dl institute 90mg dL Normalaniongapmetabolicacidosis GastrointestinalHCO3loss diarrhea lossofpancreaticorbiliarysecretions ureteroileostomyorureterosigmoidostomy sevelamerRenalacidificationdefects RTA CKD hypoaldosteronism drugs Topamax acetazolamide spironolactone amiloride trimethoprim cyclosporine pentamidine toluenefromgluesniffing Administrationofacid cationicaminoacidsinTPN EstimationofurineNH4 Theacidexcretedb