FLUIDANDELECTROLYTEMANAGEMENT水電解質(zhì)平衡

1Forsurgicalpatients:

Diseases,injuries,

operativetrauma,

lackofalimentation→metabolismofsalt,water,otherelectrolytes2TotalBodyWater

60%ofbodyweigh

50%ofbodyweight

75%to80%leanindividual>obeseperson

3WaterExchangeDrink1000～1300Food700～900

Metabolicwater300Urine800～1500Lung350Skin500Stool250250025004WaterExchangeApatientdeprivedofallexternalaccesstowatermuststillexcreteaminimumof500to800ml.ofurineperdayinordertoexcretetheproductsofcatabolism,Insensiblelossofwateroccursthroughtheskin(75%)andthelungs(25%)andisincreasedbyhypermetabolism,hyperventilation,andfever.5CompositionofUrineWaterNitrogen-containingmaterial：urea、uricacid、creatine、creatinine、aminoacidandamonia。Organiccompound：hippuricacid、glucuronate、lacticacid、ethanedioic.Electrolyte：Cl-、Na、Kandphosphate。

Littleproteinandsugar，positiveinurinepathology。6Threefunctionalcompartmentsofthebodywaterintracellularwater

40%extracellularwater

20%bodyweight60%plasma

5%interstitial

fluid15%7TotalbloodvolumeofhumanbodyGenerally

8％ofbodyweight，About5000mlforanadult。increase23％～25％inpregnancywomen。About80％

oftotalvolumeincirculationOther20%storedinliverandspleen

8154mEq/l154mEq/l153mEq/l153mEq/l200mEq/l200mEq/l

Cation Anions

Na+142Cl-103

HCO3-27

SO4= PO4≡3K+4Ca++5Mg++3

Protein16Organicacid5Cation AnionsNa+144Cl-114

HCO3-30

SO4=PO4≡3 K+4Ca++3Mg++2

Protein1

Organicacid5Cation AnionsK+150HPO4=SO4=150HCO3-10

Na+10Mg++40

Protein40

PlasmaIntestitialfluidIntracellularfluidChemicalcompositionofbodyfluidcompartment:

9OsmoticPressure

Dependsonthenumberofparticlespresentperunitvolume.1mMNaCl=sodium+chloride,contributes2mM,1mMNa2SO4=3particles,contributes3mM.1mMglucoseisequalto1mMofthesubstance.NormalOsmoticPressure

＝Cations(151)＋Anions(139)＋nonelectrolyte(10)＝300mmol/L(280～310mmol/L)10semipermeablemembrane

ThecellwallmaintainedthedifferencesinioniccompositionbetweenICFandECF.Thecellmembranesarecompletelypermeabletowater11colloidosmoticpressureThedissolvedproteinsintheplasmaareprimarilyresponsibleforeffectiveosmoticpressurebetweentheplasmaandtheinterstitialfluidcompartments.12Theeffectiveosmoticpressureintracellularextracellulardissolvedproteinsplasma

interstitial

fluid

13Theeffectiveosmoticpressure

ThedifferenceofpressurebetweentheECFandICFcompartmentsinducedbyanysubstancethatdoesnottraversethecellmembranesfreely.14CLASSIFICATIONOFBODYFLUIDCHANGESThedisordersinfluidbalance：volumedeficitorExcessconcentrationcomposition15VolumeDeficitThemostcommondisordersleadingtoanECFvolumedeficitinclude:lossesofgastrointestinalfluidsduetovomiting,nasogastricsuction,diarrhea,fistuladrainage.sequestrationoffluidinsofttissueinjuriesandinfections,intra-abdominalandperitonitis,intestinalobstruction,andburns.16VolumeExcessGenerallysecondarytorenalinsufficiency.Boththeplasmaandtheinterstitialfluidvolumesareincreased.17CONCENTRATIONCHANGESECF:Na+represent90%ofparticlesconcentration.

Hyponatremia

and

hypernatremia

canbediagnosedbyclinicalmanifestations,laboratorytests.18MechanismofHyponatremiaWaterintakeexcessSodiumintakedeficientRenalinadequacyVomite,suction19Hyponatremia

Asymptomaticuntiltheserumsodiumlevelfalls120mmolperliter.

Acutesymptomatichyponatremia:CNSsigns:Increasedintracranialpressure;tissuesignsofexcessiveintracellularwater.20Hyponatremia:(Waterintoxication)serumsodiumlevellessthan120mmol/LCNS:Moderatesevere

MuscletwitchingConvulsionsHyperactivetendonreflexesLossofreflexesincreasedintracranialpressureCardioVascular:Bpchange

Tissue:increasedsalivation

Waterydiarrhea

Renal:Oliguriaprogressingtoanuria

Metabolic:None

21MechanismofHypernatremiaWaterintakedeficientDiseasesofdigestivetractExcesslosswaterexcessperspirationVomite,diarrhea,suction22Hypernatremia:(Waterdeficit)

serumsodiumlevelgreaterthan150mmol/LCNS:Moderatesevere

RestlessnessDeliriumWeaknessManiacalbehavior

CardioVascular:Tachycardia,HypotensionTissue:DecreasedsalivaandtearsDryandstickymucousmembranesRenal:OliguriaMetabolic:Fever23MIXEDVOLUMEANDCONCENTRATIONABNORMALITIESConsequenceofthediseasestateoroccasionallyfrominappropriateparenteralfluidtherapy.1.ThemorecommonisanECFdeficitandhyponatremia(Hypotonicdehydration).2.ECFvolumedeficit+hypernatremia(Hypotonicdehydration).:glucosuria

3.ECFvolumeexcessandhypernatremia:excessivequantitiesofsodiumsalts

4.ECFvolumeexcessandhyponatremia(Waterintoxication):oliguricrenalfailure

24COMPOSITIONCHANGESCompositionalabnormalitiesinclude:concentrationchangesofpotassium,calcium,magnesiumchangesinacid-basebalance

25PotassiumThenormaldietaryintakeofpotassiumisapproximately50to100mmol.daily.98%ofthepotassiumislocatedintheICcompartmentataconcentrationof150mmol.perliter.Extracellularpotassiumis3.5~5.5mmol/L.Mostofthisisexcretedintheurine.26PotassiumAbnormaliliesHyperkalemiaExtracellularpotassium>5.5mmol/L.HypokalemiaExtracellularpotassium<3.5mmol/L.27Hyperkalemia

Significantquantitiesofintracellularpotassiumarereleasedintotheextracellularspace.Cause:severeinjuryorsurgicalstressAcidosisthecatabolicstate.oliguricoranuricrenalfailure28Hyperkalemia

Signs:Thegastrointestinalsymptomsincludenausea,vomiting,intermittentintestinalcolic,anddiarrhea.ThecardiovascularsignsareapparentontheECGinitially,withhighpeakedTwaves,widenedQRScomplex,anddepressedS-Tsegments.DisappearanceofTwaves,heartblock,anddiastoliccardiacarrestmaydevelopwithincreasinglevelsofpotassium.29HyperkalemiaTreatment:intravenousadministrationof1gm.of10%calciumgluconateunderECGmonitoringadministrationofbicarbonateandglucosewithinsulin(1μ/4gG)RapidalkalinizationoftheECFwitheithersodiumlactateorbicarbonatepromotestransferofpotassiumintocellsdefinitiveremovalofexcesspotassiumbycation-exchangeresins,peritonealdialysis,orhemodialysis.30HypokalemiaAmorecommonprobleminthesurgicalpatientmayoccurasaresultof:excessiverenalexcretion(1g/500ml)movementofpotassiumintocellsprolongedadministrationofpotassium-freeparenteralfluidswithcontinuedobligatoryrenallossofpotassiumparenteralnutritionwithinadequatepotassiumreplacement,lossofgastrointestinalsecretions.

31Hypokalemia

Thesignsofpotassiumdeficit:failureofnormalcontractilityofskeletal,smooth,andcardiacmuscleweaknesstoflaccidparalysis,diminishedtoabsenttendonreflexes,andparalyticileus.SensitivitytodigitaliswithcardiacarrhythmiasandECGsignsoflowvoltage,flatteningofTwaves,anddepressionofS-Tsegments32NormalHypokalemiaHyperkalemia33Hypokalemia

Treatmentofhypokalemiainvolves:Firstpreventionofthesestate.IntravenousadministrationofpotassiumNomorethan40mmolshouldbeaddedto1literofintravenousfluidTherateofadministrationshouldnotexceed20mmol/hourunlesstheECGisbeingmonitored.Administrationofpotassiumisabout3-6g/day1gramofKCl=13.4mmolofpotassium34CompositionofGastrointestinalSecretionsVolumeNaKClHCO3(ml/24hr)mmol/Lmmol/Lmmol/Lmmol/LSalivary150010261030StomacDuodenum100-20001405104-Ileum3000140510430Colon-603040-Pancreas100-800140575115

Bile50-800145510035

35CalciumAbnormalitiesMostofbodycalcium(99%)isfoundintheboneintheformofphosphateandcarbonate.Normaldailyintakeofcalciumisbetween1and3gm.Mostofthisisexcretedviathegastrointestinaltract,and200mg.orlessisexcretedintheurinedaily.Thenormalserumlevelisbetween2.25~2.75mmol/LThe45%istheionizedportionthatisresponsibleforneuromuscularstability.36Hypocalcemia

Thecommoncauses:

AcutepancreatitisMassivesofttissueinfectionsAcuteandchronicrenalfailurePancreaticandsmallintestinalfistulasHypoparathyroidism37Hypocalcemia

Thesymptoms(serumlevellessthan2.25mmol/L):Numbnessandtinglingofthecircumoralregionandthetipsofthefingersandtoes.Hyperactivetendonreflexes,Muscleandabdominalcramps,convulsions(withseveredeficit),Chvostek’ssignandTrousseau’signpositive38HypocalcemiaTreatment:correctionoftheunderlyingcausewithconcomitantrepletionofthedeficit.IntravenousadministrationofcalciumgluconateorcalciumchlorideCalciumlactatemaybegivenorally,WithorwithoutsupplementalvitaminD,inapatientrequiringprolongedreplacement.39Hypercalcemia

Thetwomajorcauses:

HyperparathyroidismCancerwithbonymetastasis.Thelatterismostfrequentlyseeninapatientwithmetastaticbreastcancer.40Hypercalcemia

Themanifestationsofhypercalcemiainclude:Easyfatigue,lassitude,weaknessofvaryingdegree,Anorexia,nausea,vomiting,andweightloss.Lassitude,stupor,andfinallycoma.Severeheadaches,painsinthebackandextremities,thirst.41Hypercalcemia

Treatment:vigorousvolumerepletionwithsaltsolutionslowersthecalciumlevelbydilutionandincreasedurinarycalciumexcretion.Concomitantuseoflargedosesofintravenousfurosemidetoincreaseurinarycalciumexcretion.OralorintravenousinorganicphosphatesIntravenoussodiumsulfatealsolowersserumcalcium42MagnesiumAbnormalitiesThetotalbodycontentofmagnesiumisapproximately1000mmol.,Abouthalfofwhichisinboneandthemajorotherportionbeingintracellular

Serummagnesiumconcentrationnormallyrangesbetween0.7~1.1mmol/L.

Thenormaldietaryintakeofmagnesiumisapproximately20mmol.(240mg.)daily.

Thelargerpartisexcretedinthefecesandtheremainderintheurine.Thekidneyshavearemarkableabilitytoconservemagnesium.43MagnesiumDeficiencyCause:starvation,malabsorptionsyndromes,protractedlossesofgastrointestinalfluid,prolongedparenteralfluidtherapywithmagnesium-freesolutions.Acutepancreatitis,diabeticacidosisduringtreatment.primaryaldosteronism,chronicalcoholism.44MagnesiumDeficiency

ThesignsandsymptomsThemagnesiumionisessentialforproperfunctionofmostenzymesystems,anddepletionischaracterizedbyneuromuscularandCNShyperactivity,whicharequitesimilartothoseofcalciumdeficiency.

45MagnesiumDeficiency

Treamient

Inasymptomaticpatients:oralreplacement.Severesymptomaticdeficit:Theintravenousrouteispreferablefortheinitialtreatment.Whenlargedosesaregivenintravenously,theheartrate,bloodpressure,respiration,andECGshouldbemonitoredcloselyforsignsofmagnesiumtoxicity,whichcouldleadtocardiacarrest.46MagnesiumExcessCause:1,Patientswithimpairedrenalfunction2,Early-stageburns3,Massivetraumaorsurgicalstress4,SevereECFvolumedeficit5,Severeacidosis.47MagnesiumExcess

signsandsymptomsinclude:lethargyandweaknesswithprogressivelossofdeeptendonreflexes.InterferencewithcardiacconductionECGchanges(increasedP-Rinterval,widenedQRScomplex,andelevatedTwaves)resemblethoseseenwithhyperkalemia.Somnolenceleadingtocomaandmuscularparalysisoccursinthelaterstages,anddeathisusuallycausedbyrespiratoryorcardiacarrest.48MagnesiumExcess

TreatmentCorrectinganyacidosis,ReplenishinganypreexistingECFvolumedeficitStopexogenouslyadministeredmagnesium.Acutesymptomsmaybecontrolledbyslowintravenousadministrationof2.5to5mmol.ofcalciumgluconate.(about10%calciumgluconate10~20ml)Ifelevatedlevelsorsymptomspersist,peritonealdialysisorhemodialysisisindicated.49PhosphoniumAbnormalitiesAbout85%ofphosphoniumexiteinboneNormalserumphosphoniumlevel:0.96~1.62mmol/LParticipatephosphorateofprotein,cellmembrainandacid-basebalance

50HypophosphatemiaCause:Hyperparathyroidism,severeburnorinfectionSyptom:manifestationinnervous-muscle.Treatment:administrationofsodiumglycerophosphate10ml51HyperphosphatemiaCause:acuterenalfailure,Hypoparathyroidism,acidosisSyptom:likehypocalcemia,ectopiccalcificationTreatment:treatmentofhypocalcemia,dialysis52Acid-baseBalanceAcidbase:sourceandregulation

SourceAcidvolatile（H2CO3）fixedacidMetablicfoodMaterialreleaseH+Resp.regul.Renalregul53AlkalisaltamoniafoodMetablicAcid-baseBalanceSourceSthreceiveH+54AsidandAlkaliinbodyvolatileacid:carbonicacid（H2CO3）fixedacid：H2SO4、H2PO4、ketobodiesAcid:Alkali：HCO3-、Hb-、Na2HPO4、NH355Acid-baseBalanceIntracellularPH:proteinsandphosphates,ECFspace:bicarbonate-carbonic

acidsystem

redcellhemoglobin

PHofbodyfluidsmaintainedbyseveralbuffersystemsandsubsequentlyexcretedbythelungsandkidneys.56Acidbase:sourceandregulation

Bloodbuffer:H2CO3HCO3－HPrPr－H2PO

4HPO42-－pH∝Reactquick57H+HCO3－CO2H2O+①②K+③H+④Regulationbylungandkidney58ExcreteH+andreuptakeNaHCO3HCO3－Na+HCO3－H+H2CO3H2OCO2CAHCO3－K+K+Na+Na+Proximalnephron－CO2H2OH2CO3CAH+HCO359Acid-baseBalance1、PH：NormalbloodPH:7.35~7.452、PCO2：Normal:35-45mmHg,(40mmHg)3、Buffuerexcess（BE）: Representascidosisoralkolosis,Normal:+3~-3mmol/L,(0)4、Actualbicarbonateradical（AB）：

actualHCO3-inplasma5、Standardbicarbonateradical（SB）：

HCO3-

contentmeasuredwhenPaCO2=40mmHg,HbO2=100%，T=37.0℃ NormalAB=SB=22~27mmol/L,average24mmol/L60pH

Conception：NegativelogarithmofH+concentrationinsolutionNormalvalue：Arteryblood7.35～7.45Meaning：Todistinguishacidosisoralkalosis7.357.45Acidosis6.8Alkalosis7.8deathdeathpH16nmol/L40160【H+】61Hendeison-HasselbalchequationpH=pK+logBHCO3/H2CO3=6.1+logHCO3ˉ/0.03×PaCO2

=6.1+log24/0.03×40=6.1+log20/1=7.4PKrepresentsthedissociationconstantofcarbonicacidinthepresenceofbasebicarbonateHCO3ˉrepresentthefactorofmetabolismPaCO2representthefactorofrespiration62Six-SteptotheInterpretationofArterialBloodGasWithSerumSodium,Potassium,andChlorideConcentrationsOBSERVATIONINTERPRETATIONINTERVENTIONpHotherthan7.40?Acidosisif<7.35ClinicalevaluationforcausaldiseaseAlkalosisif>7.45pH<7.20or>7.55?SeveredisorderPromptcorrectionrequiredPaco2otherthan40mmHg?VentilationcompensatesdisorderChangeventilationPaco2compensatesbasedeficitotherthanzero?Bicarbonateloss/gaincompensatesorcontributestodisorderNaCO3orHClcorrectprotonconcentrationurinepHreflectacidosis/alkalosis?Acid/alkalineurineindicatesrenalfunctioncompensatesorcontributesRenal-activedrugsorelectrolytereplacementaniongap<12mmol/L?Value>12mmol/LsuggestlacticorketoacidosisCorrecttheprimarymetabolicproblem63SimpletypeH2CO3(1)HCO3(20)－pH∝Metab(Alk)Resp.(aci)Metab.alkalosisMetab.acidosisResp.acidosisResp.alkalosisThefourtypesofacid-basedisturbances64Thefourtypesofacid-basedisturbancesAcuteChronic

pHPCO2HCO3ˉpHPCO2HCO3ˉRespacidNRespalkaNMetaacidNMetaalkaN?

65AcidosisandAlkalosis

DefectCauseRespacidRetentionofCO2DepressionofrespiratoryRespalkaExcessivelossofCO2HyperventilationMetaacidRetentionoffixedacidsDiabetes,diarrheaLossofbasebicarbonateLacticacidaccumulationMetaalkaLossoffixedacidsVomitingorgastricsuctionGainofbasebicarbonateExcessiveintakeofPotassiumdepletionbicarbonate

66RespiratoryAcidosis:Hypoventilation

PCO2iselevatedandplasmabicarbonateconcentrationisnormal.Inthechronicform,Pco2remainselevatedandbicarbonateconcentrationrisesasrenalcompensationoccurs.Cause:Airwayobstruction:Foreignbody,pneumonia,emphysema.CNS:Depression,injury,tumor.Thoracicinjury:Pneumothorax,flailchest,tracheal.Mechanicalventilation:Inadequaterateand/ortidalvolume.

67Mecanismofventilation

dysfunctionInhibitionofResp.centerResp.muscleparalysisLungdiseaseThorac.diseseObstrucstenoseofairwayInhibitResp.centerResp.m.paralysisThoraclungdisea.AirwayobstructionMal-ventilation68co2o2co2co2O2+HbHbO2o2o2o2co2co2Hb+HbcOExternalrespirationInternalrespirationAirwayPulm。alveolusbloodvesselCellRespirationcourse69RespiratoryAcidosis

Signs：cheststuffy，dyspnea，restless，cyanosisandheadachecausedbyhypoxia，DeliriumevencomaExaminationlaboratoryrevealedadecreasedpH,increasedPaCO2,HCO3ˉmayremainnormal.70RespiratoryAcidosisTreatment:Treatmentprimarydisorder.Amelioratethepatient’sventilationVentilatormaybeused71RespiratoryAlkalosiscauses:Hyperventilationapprehension,pain,hypoxia,CNSinjury,assistedventilationTreatmentisdirectedprimarilytowardthecauseofthedisorder.72Metabolicacidosis

Cause:acutecirculatoryfailurewithaccumulationoflacticacid,renalfailureretentionorproductionofacids(diabeticketoacidosis,lacticacidosis)lossofbicarbonate(diarrhea,pancreaticorsmallbowelfistula).

73Metabolicacidosis

Thecausesofmetabolicacidosiscanbedividedintotwogroupsbydeterminingtheaniongap:Normalaniongapandelevatedaniongap.Thenormalvalueis10to15mmol/L.Theunmeasuredanionsthataccountforthegaparesulfateandphosphatepluslactateandotherorganicanions.74153mmol/L153mmol/Lcationsanions

Na+142Cl-104HCO3-27

PO43SO4Organicacid5

K+4 Ca++5Protein14Mg++2

Theaniongap75AG(aniongap)Na+Cl－HCO3

－AGNormalvalue12mmol/LMeaningAG↑—Fixacid↑

Metab.Acid.AG=UA－UCAG=Na+－(HCO3-+Cl-)76Ⅰ.(metabolicacidosis)SimpleFeature:[HCO3－

]↓primelyinplasma?Acid↑AGNa+Cl－HCO3－AG↑AGNormalAGAG

Normal77Metabolicacidosis

Signs：Inmildpatient:maybeasymptomaticInseverepatient:lassitude,weakness,restlessness,deepandquickrateofrespirationIncreasedheartrate,decreasedbloodpreasure,cardiacarrhythmiasLossofreflexes,

comaDecreasedpH,HCO3ˉ

78Influence:SimpleCardiovascularsystem:

ArrhythmiaM.Ac.HypokalemiaArrhythmiaCardiaccontract.↓pH<7.2H+EffectBlockAdcontract.↓Inhib.E-Ccoupling79compensationH+SimpleBloodHCO3－CO2H2O+①Lung②CellK+③KidneyH+④80MetabolicacidosisTreatment:Treatmentprimarydisorder.ReplenishinganypreexistingECFvolumedeficitInfusionwith5%NaHCO3100~250mlIntravenousadministrationofcalciumgluconateorcalciumchloride81MetabolicAlkalosisCausesarelossoffixedacidsorgainofbicarbonateandisaggravatedbyanyexistingpotassiumdeficit.BoththepHandtheplasmabicarbonateconcentrationareelevated.Compensationoccursprimarilythroughrenalmechanisms.82InfluenceofMet.Alkolosis

1CNS：ExcitationMechanism：（1）GABA↓

（2）→braintissuehypoxia2.Nerve-Muscle:ExcitabilityCa+↓3.K+↓:Hypokalemia4.Tissuehypoxia83StomachduodenumBloodvesselH2CO3HCO3-H+HCO3-H+H+H2CO3H+HCO3-Cl-Na+Na+Cl-Cl-gastricfluidlossandmetab.Alk.PancreasHCO3-Na+esophagus84(1)H+LossStomachVomitCO2H2OH2CO3HCO3－H+H+H+H+H+H－+H+H2CO3HCO3－H+SimpleEntericcavity

H+pancreaticsecretionHCO3－Metab.Alkol85(1)

H+↓StomachVomitCO2H2OH2CO3HCO3－H+H+H+H+H+H+H+H2CO3HCO3－H+SimpleEntericcavityH+PancreaticsecretionHCO3－

Metablicalkolosis86MetabolicAlkalosisTreatment:Treatmentprimarydisorder.ReplenishinganypreexistingECFvolumedeficitIntravenousadministrationofKClIntravenousadministrationof0.1mmol/L(1mol/Lchlorideacid150ml+saline1000ml，25~50ml/h）87SaltGainandLossesInanormalindividualthedailysaltintakevariesbetween50and90mmol.(3to5gm.)assodiumchloride.Balanceismaintainedprimarilybythekidneys,whichexcretetheexcesssalt.88SaltGainandLosses

SodiumExchange AverageSodiumGainDiet50-90mmol/day

SodiumlossSkin(sweat)10-60mmol/dayUrine10-80mmol/dayIntestine0-20mmol/day89FLUIDANDELECTROLYTETHERAPY

lactatedRinger'ssolution:AgoodavailableisotonicsaltsolutionforreplacinggastrointestinallossesandECFvolumedeficits.Thissolution

isphysiologicandcontains130mmol.ofsodiumbalancedby109mmol.ofchlorideand28mmol.oflactate.Lactateisusedinsteadofbicarbonate,Thelactateisreadilyconvertedtobicarbonatebytheliverafterinfusion.90PREOPERATIVEFLUIDTHERAPYPreoperativeevaluationandcorrectionofexistingfluiddisordersCorrectionofVolumeChanges:VolumedeficitCorrectionofConcentrationChanges:severesymptomatichyponatremiaorhypernatremia

CompositionandMiscellaneousConsiderations:Correctionofpotassiumdeficits

91INTRAOPERATIVEMANAGEMENTOFFLUIDSPreoperativereplacementofECFvolumeincompleteBloodlostduringtheoperativeprocedure:usuallyunnecessarytoreplaceb