水电解质代谢与酸碱平衡失调-E070914-2010(5)医学

1FluidsandElectrolytesManagementoftheSurgicalPatientZongfangLi(李宗芳),MD.PHDProfessorofGeneralSurgerylzf2568@2和谐社会3旱灾4水灾5

Case1：

王某，女，23岁。以“呕吐、腹泻36小时”入院患者于36小时前，吃剩饭后即感上腹不适，继则腹痛、呕吐频繁，呕吐出大量食物和胃液，并腹泻十余次，为大量黄色稀水便。逐渐出现口渴、尿少、恶心、厌食、软弱无力。半小时前便后起立时，突然晕倒在厕所，救醒后速送医院求治。入院查体：体温37.8℃,脉搏120次/分.呼吸深快(28次/分),血压90/70mmHg，体重50Kg，神志淡漠，面色苍白，皮肤弹性差，眼眶凹陷。肢端湿泠，腹部轻度深压痛。

化验：①血常规：RBC550万/mm3，Hb12g%，WBC15000/mm3，N80%；②尿常规：比重1.030,强酸性；③粪常规：黄色稀水便，WBC(＋)；④血清Na+138mEg/L、K+3.5mEg/L、CO2CP30VOL%，BUN39mg/ml。

Diagnosis:?Prescription:?6

Case2

赵××，男性，60岁，体重65Kg

“胆囊切除，胆总管探查术后第一天”

术后从胃管内共抽出液体600ml。

T管引流出胆汁400ml。烟卷引流出渗液约240ml

体温持续在38.2℃Prescriptionoffluidreplacement:?7

BodyFluid&ItsCompartmentsComposition:Water＋ElectrolytesVolume:50%（female）～60%（male）

80%（infant）ofbodyweight

FACTOR：sex、age、lean&fatDistribution(figure1):

ExtracellularFluid（20%）Plasma5%、InterstitialFluid15%

IntracellularFluid（35%～40%）Skeletalmuscle35%Electrolyte：ECF：Na＋/CI－、HCO3－、proteinICF：K＋、Mg＋＋/P3－、proteinTheeffectiveosmoticpressureinthetwocompartmentsareconsideredequal,about290-310mOsm／L.

以上的稳定持机体新陈代谢正常进行的保证8FunctionofWater

Waterisoneofthemostimportantmaterialtomaintainthemormalfunctionsofhumanbody.

人只饮水可生存十日之久，无水只能生存数日

①调节体温Regulatebodyheat②促进物质代谢Facilitatemetabolism:

溶解dissolve,、运输

transportation③润滑作用lubrication9FunctionofElectrolytes①MaintainingtheOsmoticPressureandthebalanceofwater：

K＋/HPO4－；Na＋/CI－②MaintainingAcid-baseBalance：Buffersysteminbodyfluids.③Maintainingtheexcitabilityofnerveandmuscle：

[Na＋]＋[K＋]theexcitability∝[Ca＋＋]＋[Mg＋＋]＋[H+]④K＋

istheactivatorofmanyenzymesinhumanbody：

K＋

takepartinthebiosynthesisofglycogenandprotein.10水的摄入与排出

Watergainandloss

每天代谢产生固体废物35～40g，每g至少需尿15ml将它排出。因此，每天尿量不应少于500ml（1.030）.但每天尿量1500ml±（1.012）时肾脏负担最轻。∴Anormaladultneedatleast1500mlwatereveryday,but2500mlismorereasonable.H2OGain（ml）H2OLossOralfluids1000～1500 Urine1000～1500Solidfoods700 Stool150endogeny300 InsensibleSkin500Lungs350Total2000～2500Total2000～250011ElectrolyteContentofBodyFluid1正常人血浆or血清中的电解质浓度

positiveionmEg/LnegativeionmEg/LNa＋

142CI－

103K＋

5HCO3－

27Ca＋＋

HPO4-22

SO4-21Mg＋＋

organicacid5Protein16Total154Total15412ElectrolyteContentofBodyFluid2各种消化液每日分泌量（ml）及其电解质浓（mEg/L）DigestivejuiceVolumeofsecretion(ml/day)H+(mEq/l)Na+(mEq/l)K+(mEq/l)Cl-(mEq/l)HCO3-(mEq/l)saliv18Gastricjuice20000~9040~10010~4550~1400~5Bilejuice700135~145580~11035Pancreaticjuice800135~185550~7090Smallintestinaljuice>3000105~1355~20100~12020~30TotalVolume>8000,Only150mlfluidexcretethroughdejectainnormalstate.Duringvomitinganddiarrhea,thebodyfluidwillchange.Lossofanydigestivejuicewillleadtospecificsequent.13MetabolizeofElectrolytesElectrolytesisingestedfromfood,comeintoeverytissuethroughblood,andexcretedfromkidneymostly.Theurineofadultcontains:

natrium(≈NaCI6～9g)andkalium(2～3g).TheexcretionofNa+andK+fromkidneyNa+:themoreingested,themoreexcreted,viceversa.noingested,noexcreted.K+:themoreingested,themoreexcreted,viceversa.noingested,stillexcerted.14AdjustofBodyFluidBalance1可以分为:出入量的调节；细胞内外的调节；血管内外的调节。晶体渗透压血浆胶渗压毛细管通透性毛细管静水压饮水and排尿主要通过肾脏，其调节功能受神经、内分泌反应影响首先：Hypothalamus—neurohypophysis—ADHsystemosmoticpressure然后：Rein–angiotensin–aldosteronesystemvolume

但当血容量↓↓↓时，机体优先保持和恢复血容量，→使重要生命器官的灌流得以保证，维护生命。

15AdjustofBodyFluidBalance2下丘脑、垂体后叶、抗利尿激素S体内水份丧失，细胞外液渗透压↑（灵敏度2%）

口渴、饮水增加下丘脑、垂体后叶分泌ADH远曲肾小管、集合管上皮细胞吸收水、尿量保留水份于体内细胞外液渗透压↓细胞外液渗透压16细胞外液↓（血容量↓）BP↓肾素醛固酮S

交感神经兴奋压力感受器（肾小球入球小动脉）肾小球滤过率↓经远曲肾小管的Na+↓钠感受器（远曲肾小管致密斑）肾小球旁细胞分泌肾素血管紧张素原血管紧张素Ⅰ血管紧张素Ⅱ肾上腺皮质球状带醛固酮合成分泌↑血浆中远曲肾小管再吸收Na＋↑→CI－↑→H2O↑（排泌K＋、H＋↑）细胞外液↑循环血量↑BP↑AdjustofBodyFluidBalance317神经-内分泌对细胞外液的调节细胞外液变化渗透压↑容量↓下丘脑肾素↑口喝ＡＤＨ↑血管紧张素Ⅰ饮水↑保水（尿量↓）血管紧张素Ⅱ醛固酮↑保Na（尿Na↓）渗透压↓容量↑细胞外液恢复AdjustofBodyFluidBalance418BodyFluidAbnormalitiesTotalBodyWaterLossDehydration=saltdeficient+waterdeficientInsurgicalpatients,waterandsaltdeficitsmoreoftenoccurtogether.

Dehydrationcanbeclassifiedintothreecategories:hypertonic,hypotonic,isotonic.19高渗性脱水.1

Hypertonicdehydration

Definition:waterdeficient>sodiumdeficientPNa+>150mEq/L(hypertonia)Cause:Intakedeficient--unabletoregulateintake,fountaindiscontinuity

Overabundantloss–

profuse

sweatingfromardentfever,excessivediuresisIt’salsocalledprimarywaterdeficits.Pathophysiology:ECFvolumedeficitaccompaniedbyhypernatremia,ADH↑，aldostenrone↑20高渗性脱水.2

Hypertonicdehydration

LaboratoryInvestigation:WBC↑、Concentratedblood,increasedurinespecificgravity(spgr≻1.035).Plasmaprotein,Potassium,Natrium,Chlorine,BUN,andOsmoticpressureareallincreased.ExtentWeight↓%ClinicalfindingLight2ThirstyModerate3~4Severethirsty,Ligulaxeransis,Flexibilityofskindecerase,Sunkeneyes,Apathy,Xeransisinaxillaandinguen,Oliguria,increasedurinespecificgravitySevereAbove5~6Severethirsty+obvioussymptomofcentralnervoussystem,Mania,Hallucination,Phrenitis,Hyperpyrexia,Eclampsia,coma,DecreasedBP,Shock212.低渗性脱水.1

Hypotonicdehydration

Definition:waterdeficient<sodiumdeficientPNa+<135mEq/L(hypotonia)Cause:

Chronicbodyfluidlossor

bodyfluidlossarereplacedwithonlywithnoly5%dextroseinwaterorahypotonicsodiumsolution.It’salsocalledChronicwaterdeficits.Pathophysiology:

ECFvolumedeficitandhyponatremia,Circulationfailurepresentsintheearlystage.ADHdecreasesinearlystageandincreasesinterminalstage,Increasedaldostenrone222.低渗性脱水.2Hypotonicdehydration

LaboratoryInvestigation:Concentratedblood,increasedMCV,MCHC,Oliguria,non-increasedurinespecificgravity,SeverelydecreasedNatriumandChlorineinurine.IncreasedplasmaproteinandBUN,DecreasedplasmaNatriumandChlorine,DecreasedOsmoticpressure.ExtentΔNaCl/kgBWPNa(meq/L)ClinicalfindingLight0.5g130~135Tired,Apathy,Faint,extremeanaesthesia,Withoutthirsty,decreasedurineNa,normalurinevolumeModerate0.6~0.8g120~130Theabovesymptomaggravate,Anorexia,Nausea,Vomiting,Sleepiness,Collapsedveinsandpulse,UnsteadyordecreasedBP,illegibleeyesight,Orthostaticfaint,Oliguria,withoutchlorideinurine

SevereAbove0.8gbelow120CNSsymptom:Dottiness,Jerk,Decreasedtendonreflexes,Anesthsiaofdistalextremities,shock.233.等渗性脱水.1

IsotonicdehydrationDefinition:ThelossoffluidiswaterandelectrolytesinapproximatelythesameproportionasthatinthichtheyexistinnormalECF.PlasmaNa+isnormal.(isotonia)Cause:Acutelossesofgastrointestinalfluidsduetovomiting,diarrhea.Ponderosusascitedrainage,Earlystageoflargeareaempyrosis(exudation).It’salsocalledacutewaterdeficits.Pathophysiology:DecreasedECF,Severevolumedepletion,Increasedaldostenrone

24Clinicalfinding:Hydropeniasyndrome:Thirsty,Oliguria,Withthesodiumdeficit:Anorexia,nausea,adynamia.Above4%ofweight:Symptomofseverevolumedepletion.Absentperipheralpulses,Coldextremities,unsteadyordecreasedBP.Above6%ofweight:peripheralcirculatoryfailure,ShockItisoftenaccompaniedwithmetabolicacidosis.Whenthegastricjuicelostseverely,itwillbeaccompaniedwithmetabolicalkalosis.LaboratoryInvestigation:Concentratedblood,NormalMCV,MCHC,Increasedurinespecificgravity,DecreasedNatriumandChlorineinurine.IncreasedplasmaproteinandBUN,NormalplasmaNatrium,Chlorine,andOsmoticpressure3.等渗性脱水.2

Isotonicdehydration25Thetreatmentoftheprimarydiease.Restoringvolumeandthedeficientelectrolytes.Thecontentsoffluidreplacementcontain:thevolumeofphysiologicalrequirements,Preexistingdeficits,andongoinglosses.Thereplacementofexistingdeficitsofvolume:theextentandcategoryofdehydrationdecidethevolumeandthetypeofsolution(G/N),respectively.Hypertonicdehydration----5-10%GlucoseSolution.

Hypotonicdehydration----normalsalineor3~5％saline(Hypertonic)Isotonicdehydration---5%GNSTakeorallyasfaraspossible,supplyfromveinswhenthepatientcannottakeorally.

2.脱水的处理原则

Thetherapicprincipleofdehydration26ElectrolyteDisordersHypokalemia27①

Transportationbetweenextra-andintracellular:Physiologicfactor:Na＋－K＋ATPenzyme,Digitaloiddrugs，Catecholamine,Insulin,Bloodglucoseconcentration,BloodPotassiumconcentration,Heavyexercise.

Pathologicfactor:PlasmapH(inorganicacid),Hypertonia,histoclasia,excessivegrowth.②Regulationofbody：

IntakeandexcretedofPotassium：

Kidney：aldosterone(actatcollectingtubuletopromotethesecretionofPotassium)glucocorticosteroid(keepnatriumandexcretePotassium)AdjustofSerumPotassium28Definition:SerumPotassium<3.5mmol/L.

体内缺钾300mmol以上时，血清钾才下降。Cause:

①

钾摄入量不足：禁食、厌食、拒食时间较久②

钾损失过多：大量出汗、呕吐、腹泻、胃肠减压、肠瘘；利尿药、肾小管酸中毒、棉酚中毒Conn综合征et.al.③

体内分布异常：糖元、蛋白合成，碱中毒，低钾性周期性麻痹，儿茶酚胺制剂，细胞生长过速，钾进入细胞内Hypokalemia129Clinicalfinding：

钾的丢失主要来自细胞内，C内含钾很丰富，故机体丢钾350mmol以下时，无临床表现；临床表现的严重与否、取决于钾丢失的多少及丢失的速度。

临床表现包括以下6个方面：

①循环系统；②神经肌肉系统；③

CN系统；

④泌尿系统；⑤消化系统；⑥肌纤维溶解；⑦酸碱平衡失调。Hypokalemia230①Circulationsystemcardiacdamage：坏死、细胞侵润、瘢痕－心衰arhythmia：期前收缩、阵发性心动过速、室扑或室颤、猝死Susceptibletodigitalisintoxication：

ECG：K＋﹤3.0，U波出现、TU融合

K＋﹤2.5，ST段下移、T波倒置

U波出现，体内缺钾400mmol以上

hypopiesia：植物N功能紊乱、血管扩张引起

Hypokalemia3临床表现：31②neuromuscularsystem

骨骼肌：肌无力(K＋﹤3.0)、肌痛、肌麻痹、软瘫(K＋﹤2.5)

平滑肌：腹胀、便秘、麻痹性肠梗阻、尿潴留

K＋是许多酶的激活剂,与三羧循环.乙酰胆碱合成有关③centralnervoussystem

神志淡漠、目光呆滞、疲乏；烦躁不安、情绪激动、精神不振；嗜睡、定向力障碍、昏迷(K＋﹤2.0)

与糖代谢障碍、能量生成及乙酰胆碱生成减少有关

Hypokalemia4临床表现：32④urinarysystem

多尿、夜尿增多、甚至肾衰－煩渴、多饮

缺钾可引起肾小管上皮细胞损害；体内缺钾200mmol时肾小管浓缩功能↓⑤digestivesystem

食欲不振、恶心、呕吐、腹胀、便秘⑥musclefibrolysis

K＋﹤2.5，肌红蛋白尿、甚至急性肾衰

Hypokalemia5临床表现：33Hypokalemia6临床表现：⑦cid-basedisturbance

metabolicalkalosis

paradoxicalaciduria低钾时，①C内K＋与C外H＋交换↑，

C内H＋↑→C内酸中毒；

C外H＋→C外液碱中毒。②肾保Cl-↓，尿Cl-↑，

Na＋重吸收时不能与Cl-

而与HCO3-→HCO3-重吸收↑低钾时，代谢性碱中毒肾小管上皮细胞内K＋↓，

K＋与肾小管管腔中的Na＋交换↓，H＋与Na＋交换↑，尿呈酸性，肾排H＋↑34Diagnosis：主要依靠病史＋表现血清Ｋ＋<3.5mEg/L,EKG特征改变→确诊注意:酸中毒、脱水时，重症才出现Therapy：

积极治疗原发病，必要时补充钾盐。

注意：尽量口服，不能口服者V补给（常用10％KCl）；尿少不补K；浓度不宜过高（≤0.3%）；速度不宜过快(<80d/分)；总量不宜过多(6g左右)

最好加入NS，加入GS有可能使血钾更低；丢正糖尿病酮症酸中毒时，应特别注意低钾可能。Hypokalemia735Acid-baseBalance36

Theph(thenegativelogarithmofthehydrogenionconcentrationPH=7.35~7.45)ofthebodyfluidsisnormallymaintainedwithinnarrowlimitsdespitetheratherlargeloadofacidproducedendogenouslyasaby-productofbodymetabolism.包括四个方面:A.buffersystem

（作用快,仅能应付急需）

HCO3－

27mmol/L2