化膿性腦膜炎(英文)

PurulentMeningitisinChildrenJiangLiDepartmentofNeurologyChildren’sHospitalChongqingUniversityofMedicalSciencesAcuteinfectionofcentralnervoussystem(CNS).90%ofcasesoccurintheageof1mo-5yr.Theinflammationofmeningescausedbyvariousbacteria.Commonfeaturesinclinicalpracticesinclude:fever,increasedintracranialpressure,meningealirritation.

Oneofthemostpotentiallyseriousinfections,associatedwithhighmortality(about10%)andmorbidity.PurulentMeningitisEtiology1.1Pathogens:Mainpathogens:Neissriameningitidis,streptoccuspneumoniae,Haemophilusinfluenzae.(2/3ofpurulentmeningitisarecausedbythesepathogens)Pathogensinspecialpopulations(neonate&<3moinfants,malnutrition,immunodeficiency):gramnegativeentericbacilli,groupBstreptococci,staphlococcusaureus

1.2Majorriskfactorsformeningitis

ImmatureimmunologicfunctionandattenuatedimmunologicresponsetopathogensLowlevelofimmunoglobulin,defectsofcomplementandproperdinsystemImmatureorimpairedblood-brain-barrier(BBB)

ImmatureBBBfunction:maturationatabout1yrImpairedBBB:Congenialoracquireddefectsacrossmucocutaneousbarrier

1.3Accessofbacteriainvasion

Typicalaccess---hematogenousdissemination

Bacteriacolonizingthemucousmembranesofthenasopharynxinvasionintolocaltissuebacteremiahematogenousseedingtothesubarachnoidspace

Modeoftransmission:PersontopersoncontactthroughrespiratorytractsecretionsordropletsBacteriaspreadtothemeningesdirectly:throughanatomicdefectsintheskullorheadtraumaInvasionfromparameningealorgans:suchasparanasalsinusesormiddleearAccessofbacteriainvasion2.PathologyStructureofmeningesCharacterizedbyleptomeningealandperivascularinfiltrationwithpolymorphonuclearleukocytesandaninflammatoryexudate.Exudatewhichmaybedistributedfromconvexityofbraintobasalregionofcranium.Exudateismorethicknessduetostreptococcuspneumoniaethanotherpathogens.Pathology3.ClinicalmanifestationsTheyoungerthechildis,thehigherincidenceofmeningitiswillbe.?-2/3ofcasesoccurlessthan1yrofage.Modeofpresentation:

Acuteorfulminantonset:symptomsandsignsofsepsis;meningitisevolverapidlyoverafewhoursanddeathwithin24hours;usuallyinfectedwithNeissriameningitides(N.meningitides).

Subacuteonset:Precedebyseveraldaysofupperrespiratorytractorgastrointestinalsymptoms;difficulttopinpointtheexactonsetofmeningitis;usuallywithmeningitisduetoHaemophilusinfluenzae(Hinfluenzae)andstreptoccuspneumococcus(Spneumococcus).ModeofpresentationCommonfeaturesofmeningitis:

signsofsystemicinfection:fever(90-95%),anorexia,shock,alterationofmentalstatusandconsciousness

neurologicalsigns:

increasedintracranialpressure:headache,vomiting(82%),herniation

meningealirritation:nuchalrigidity(77%),kernigsign,brudzinskisign

Clinicalmanifestationsbrudzinskisign

Seizure(20-30%)

FocalorgeneralizedDuetocerebritis,infarction,electrolytedisturbancesFrequentlynotedwithHinfluenzae&SpneumococcalmeningitisPersistafter4thdayanddifficulttotreatwithpoorprognosisClinicalmanifestations

Clinicalmanifestations

AlterationofmentalstatusandconsciousnessIncluding:irritability,lethargy,stuporobtundation,comaDuetoincreasedintracranialpressure,cerebritis,hypotensionOftenwithpneumococcalormeningococcalmeningitisComatosepatientswithapoorprognosisThesymptomsandsignsarenotevidentinneonatesandinfantsyoungerthan3moofage;andpatientsalreadyreceivedirregularantibiotictherapy.ClinicalmanifestationsSignsofsystemicinfectionIncreasedintracranialpressuremeningealirritationTypical(olderchildren)Fever,alteredconsciousness,seizureHeadache,vomiting,herniationnuchalrigidity,backpain,kernigsign,brudzinskisignAtypical(neonate&<3moinfant)Fever,normaltemperatureorhypothermia;minimorsubtleseizure;poorfeeding;lessactivityScream,frown;bulgingorfullfontanel;wideningofthesuturesNotevidentComparisonofthemanifestationsofmeningitisbetweendifferentagegroupsClinicalmanifestations4.DiagnosisEarlierdiagnosisandpromptinitiationofeffectiveantibiotictreatmentiscriticalforminimizingsequelaeofpurulentmeningitis.Suspectedcases:febrileinfantswithseizure,meningealirritability,increasedintracranialpressure,alteredmentalstatusPayattentiontotheatypicalsymptomsandsignsinneonate,infantandpatientalreadyreceivedirregularantibiotictherapy

Diagnosisisconfirmedbyanalysisofcerebrospinalfluid(CSF)

Suggestionbacterialmeningitis

Increasedpressure(90%)Appearance:slightlycloudytopurulentRaisedwhitebloodcells,consistingchieflyofpolymorphonuclearleukocytesRaisedproteinconcentration,decreasedglucoseconcentration(80%)

Diagnosis

Confirmationofthediagnosis:isolationfromtheCSFofaspecificbacterialpathogenbymicroscopyorapositivecultureorrapidantigen-detectiontestofCSF

Gram-stainedsmearofCSF:identifythecausativeorganismin70-90%ofcases

CSFculture:positiveinabout80%ofcases.definitivediagnosis,determinationofantibioticsensitivity.PCR:amplifiesbacterialDNA(Hinfluenzae,N.meningitidis)Diagnosis5.Differentialdiagnosis

Purulentmeningitiscausedbydifferentpathogens

Neissriameningitidis:Occurinepidemics(typeA,C),whichismorecommoninspring,orsporadicalltheyear(typeB,C,Y)Suddenonsetwithvariouscutaneoussigns(petechiae,purpura,oranerythematousmacularrash)

Streptococcuspneumoniae:Younginfants(<1yr)aremostsusceptiblepopulationPeakseason:springandwinterEasiertohavesubduraleffusionand

hydrocephalusEasilyhaveaprotractedcourseandrelapseDifferentialdiagnosis

HaemophilusinfluenzaeOccurspredominantlyininfants2moto2yrofageManycasesareinwinterHigherincidenceofsubduraleffusion

Otherspathogens:staphylococcusaureus,gramnegativeentericbacilliSpecialsusceptiblepopulation:neonate,<3moinfants,malnutrition,immunodeficiencySevereinfection,difficulttotreatDifferentialdiagnosis

Meningitiscausedbyothermicroorganisms

Viralmeningitis/encephalitis:

Lessseveresystemicinfectioussymptoms

Usuallynotdevelopafter2-3weeks

CSF:normalglucose

Differentialdiagnosis

Tuberculousmeningitis

Subacuteonsetandprogress

AhistoryofclosecontactwithknowncasesoftuberculosisEvidenceofacuteorhealedtubercularinfectiononchestx-rayTuberculinskintest:OT,PPDCSFDifferentialdiagnosisDiseasePressure(Kpa)aspectTotalWBC(x106/L)Protein(g/L)Glucose(mmol/L)smearsculturesnormal0.69-1.96(0.29-0.78)clear0-5(0-20)0.2-0.4(0.2-1.2)2.2-4.4--Purulentmeningitis

cloudy

(PMN)

(1-5)

(<2.2)Gram’sstain++Tuberculousmeningitis

Normalorcloudy

(MN)

AFBstain+

Viralmeningitis/encephalitisNormalor

NormalNormalor(MN)Normalor

(<1)normal-

FungalmeningitisNormalor

Normalorcloudy

(MN)

Indiainkprep+

Cerebrospinalfluidinneurologicinfection6.Complicationsandsequelae6.1SubduraleffusionDefinitivediagnosis:volumeoffluidinsubduralspace>2ml,protein>0.4g/L,Incidence:developin10-30%ofpatients,asymptomaticin85-90%ofpatients;especiallycommonininfants4-6monthofage(rareinchildrenover1yr);Causativeorganisms:45%ofcasesofmeningitiscausedbyHinfluenzae,30%bySpneumoniae,9%byNmeningitidissubduraleffusion

Indications:NoresponsetoasensitiveantibiotictherapyProlongedfeverorfeverreoccurringafteranafebrileintervalwitheffectivetreatmentBulgingfontanel,wideningofsutures,enlargingheadcircumference,emesis,seizure,alteredconsciousness.ImprovedCSFprofilewithmoreseriousclinicalmanifestationssubduraleffusionDiagnosismethods:

CranialtranslucenttestBultrasonicexaminationandCTSubduralspacepuncturesubduraleffusionnormalsubduraleffusion6.2Ventriculitis6.3hydrocephalusComplicationsCirculationofcerebrospinalfluid(CSF)6.2VentriculitisUsuallyoccursinneonatesandinfants(<1yr),withsevereprognosisThemaincauseisdelayeddiagnosisandtreatmentofmeningitis.

ComplicationsDiagnosis:Bultrasonicexaminationorneuroimagingstudies(CT,MRI):enlargedlateralventricleLateralventriclepuncture:bacteriaandinflammatorycellsinventricularfluid,WBC>50x106/L,Glucose<1.6mmol/L,orprotein>400mg/L.VentriculitisCirculationofcerebrospinalfluid(CSF)6.3hydrocephalus:Communicatinghydrocephalus:adheredordestroyedarachnoidgranulationaroundthecisternatthebaseofthebrainObstructivehydrocephalus:followingobstructedofthecerebralaqueduct,ortheforaminaofMagendieandLuschka6.4others:Deafness,blindness,paralysis,epilepsy,mentalretardationComplicationsTreatment7.1AntibacterialtherapyTherapyprinciples:earlytreatment,antibioticssusceptibletopathogensandwithhighpermeabilitythroughBBB,givenintraveninously,enoughdose,enoughcourseofantibiotictherapy

Susceptibletopathogens

Firstchoice:Cefotaxime,Ceftriaxone(3drgenerationofcephalosporins,highpermeabilitythroughBBB,productsofmetabolismalsohaseffect,CSFsterilizationwithin24h)Otherchoice:Penicillin,Chloromycin,Cefuroxime,Ceftazidime(delayedeffecttomakeCSFsterile,highincidenceofrelapseanddeafness)AntibacterialtherapyEtiologyStandardantibioticsofchoiceDurationoftherapyH.influenzaeCefotaxime/Ceftriaxone7-10daysN.meningitidisCefotaxime/Ceftriaxone7daysS.pneumoniaeCefotaxime/Ceftriaxone2-3weeksStaphlococcusaureusSemisyntheticpenicillins(Oxacillinsodium,Cloxacillinsodium),Norvancomycin>3weeksE.coliCefotaxime/Ceftriaxone(or+ampicillin)>3weeksUnknownCefotaxime/Ceftriaxone+ampicillin>2-3weeksAntibiotictherapyofbacterialmeningitisMaintenancefluidandthermalenergysupplement:Fluidadministration:60-80ml/kg/dayFluidinfusionwithdehydrationtherapy7.2Supportivecare

Treatment

increasedintracranialpressure

Osmotictherapy:intravenousmannitol0.5-1g/kg/everytime,q4-6hCombinationwithintravenousdexamethasone:0.3-0.5mg/kg/dayEndotrachealintubationandhyperventilationTreatment

Subduraleffusion

FewvolumecouldbeabsorbedwithtreatmentspontaneouslySubduralpuncture:takeout15ml/eachtime(unilateralpuncture),lessthan30ml/eachtime(bilateralpuncture),everydayoreveryotherdayStrippingoperation:forthecasesnotcureafter3-4weeksTreatmentOthers:

Ventriculitis:lateralventriclepunctureandinjectionofantibioticslocallyEpilepsy:AEDsTreatment第一節(jié)活塞式空壓機(jī)的工作原理第二節(jié)活塞式空壓機(jī)的結(jié)構(gòu)和自動(dòng)控制第三節(jié)活塞式空壓機(jī)的管理復(fù)習(xí)思考題單擊此處輸入你的副標(biāo)題，文字是您思想的提煉，為了最終演示發(fā)布的良好效果，請(qǐng)盡量言簡(jiǎn)意賅的闡述觀點(diǎn)。第六章活塞式空氣壓縮機(jī)

piston-aircompressor壓縮空氣在船舶上的應(yīng)用：

1.主機(jī)的啟動(dòng)、換向；

2.輔機(jī)的啟動(dòng)；

3.為氣動(dòng)裝置提供氣源；

4.為氣動(dòng)工具提供氣源；

5.吹洗零部件和濾器。

排氣量:單位時(shí)間內(nèi)所排送的相當(dāng)?shù)谝患?jí)吸氣狀態(tài)的空氣體積。單位：m3/s、m3/min、m3/h第六章活塞式空氣壓縮機(jī)

piston-aircompressor空壓機(jī)分類：按排氣壓力分：低壓0.2～1.0MPa；中壓1～10MPa；高壓10～100MPa。按排氣量分：微型<1m3/min；小型1～10m3/min；中型10～100m3/min；大型>100m3/min。第六章活塞式空氣壓縮機(jī)

piston-aircompressor第一節(jié)活塞式空壓機(jī)的工作原理容積式壓縮機(jī)按結(jié)構(gòu)分為兩大類：往復(fù)式與旋轉(zhuǎn)式兩級(jí)活塞式壓縮機(jī)單級(jí)活塞壓縮機(jī)活塞式壓縮機(jī)膜片式壓縮機(jī)旋轉(zhuǎn)葉片式壓縮機(jī)最長(zhǎng)的使用壽命-

----低轉(zhuǎn)速（1460RPM），動(dòng)件少（軸承與滑片），潤(rùn)滑油在機(jī)件間形成保護(hù)膜，防止磨損及泄漏，使空壓機(jī)能夠安靜有效運(yùn)作；平時(shí)有按規(guī)定做例行保養(yǎng)的JAGUAR滑片式空壓機(jī)，至今使用十萬小時(shí)以上，依然完好如初，按十萬小時(shí)相當(dāng)于每日以十小時(shí)運(yùn)作計(jì)算，可長(zhǎng)達(dá)33年之久。因此，將滑片式空壓機(jī)比喻為一部終身機(jī)器實(shí)不為過?；?葉)片式空壓機(jī)可以365天連續(xù)運(yùn)轉(zhuǎn)并保證60000小時(shí)以上安全運(yùn)轉(zhuǎn)的空氣壓縮機(jī)1.進(jìn)氣2.開始?jí)嚎s3.壓縮中4.排氣1.轉(zhuǎn)子及機(jī)殼間成為壓縮空間，當(dāng)轉(zhuǎn)子開始轉(zhuǎn)動(dòng)時(shí)，空氣由機(jī)體進(jìn)氣端進(jìn)入。2.轉(zhuǎn)子轉(zhuǎn)動(dòng)使被吸入的空氣轉(zhuǎn)至機(jī)殼與轉(zhuǎn)子間氣密范圍，同時(shí)停止進(jìn)氣。3.轉(zhuǎn)子不斷轉(zhuǎn)動(dòng)，氣密范圍變小，空氣被壓縮。4.被壓縮的空氣壓力升高達(dá)到額定的壓力后由排氣端排出進(jìn)入油氣分離器內(nèi)。4.被壓縮的空氣壓力升高達(dá)到額定的壓力后由排氣端排出進(jìn)入油氣分離器內(nèi)。1.進(jìn)氣2.開始?jí)嚎s3.壓縮中4.排氣1.凸凹轉(zhuǎn)子及機(jī)殼間成為壓縮空間，當(dāng)轉(zhuǎn)子開始轉(zhuǎn)動(dòng)時(shí)，空氣由機(jī)體進(jìn)氣端進(jìn)入。2.轉(zhuǎn)子轉(zhuǎn)動(dòng)使被吸入的空氣轉(zhuǎn)至機(jī)殼與轉(zhuǎn)子間氣密范圍，同時(shí)停止進(jìn)氣。3.轉(zhuǎn)子不斷轉(zhuǎn)動(dòng)，氣密范圍變小，空氣被壓縮。螺桿式氣體壓縮機(jī)是世界上最先進(jìn)、緊湊型、堅(jiān)實(shí)、運(yùn)行平穩(wěn)，噪音低，是值得信賴的氣體壓縮機(jī)。螺桿式壓縮機(jī)氣路系統(tǒng)：

A

進(jìn)氣過濾器

B

空氣進(jìn)氣閥

C

壓縮機(jī)主機(jī)

D

單向閥

E

空氣/油分離器

F

最小壓力閥

G

后冷卻器

H

帶自動(dòng)疏水器的水分離器油路系統(tǒng)：

J

油箱

K

恒溫旁通閥

L

油冷卻器

M

油過濾器

N

回油閥

O

斷油閥冷凍系統(tǒng)：

P

冷凍壓縮機(jī)

Q

冷凝器

R

熱交換器

S

旁通系統(tǒng)

T

空氣出口過濾器螺桿式壓縮機(jī)渦旋式壓縮機(jī)

渦旋式壓縮機(jī)是20世紀(jì)90年代末期開發(fā)并問世的高科技?jí)嚎s機(jī)，由于結(jié)構(gòu)簡(jiǎn)單、零件少、效率高、可靠性好，尤其是其低噪聲、長(zhǎng)壽命等諸方面大大優(yōu)于其它型式的壓縮機(jī)，已經(jīng)得到壓縮機(jī)行業(yè)的關(guān)注和公認(rèn)。被譽(yù)為“環(huán)保型壓縮機(jī)”。由于渦旋式壓縮機(jī)的獨(dú)特設(shè)計(jì)，使其成為當(dāng)今世界最節(jié)能壓縮機(jī)。渦旋式壓縮機(jī)主要運(yùn)動(dòng)件渦卷付，只有磨合沒有磨損，因而壽命更長(zhǎng)，被譽(yù)為免維修壓縮機(jī)。

由于渦旋式壓縮機(jī)運(yùn)行平穩(wěn)、振動(dòng)小、工作環(huán)境安靜，又被譽(yù)為“超靜壓縮機(jī)”。

渦旋式壓縮機(jī)零部件少，只有四個(gè)運(yùn)動(dòng)部件,壓縮機(jī)工作腔由相運(yùn)動(dòng)渦卷付形成多個(gè)相互封閉的鐮形工作腔，當(dāng)動(dòng)渦卷作平動(dòng)運(yùn)動(dòng)時(shí)，使鐮形工作腔由大變小而達(dá)到壓縮和排出壓縮空氣的目的?；钊娇諝鈮嚎s機(jī)的外形第一節(jié)活塞式空壓機(jī)的工作原理一、理論工作循環(huán)（單級(jí)壓縮）工作循環(huán)：4—1—2—34—1吸氣過程

1—2壓縮過程

2—3排氣過程第一節(jié)活塞式空壓機(jī)的工作原理一、理論工作循環(huán)（單級(jí)壓縮）

壓縮分類：絕熱壓縮：1—2耗功最大等溫壓縮：1—2''耗功最小多變壓縮：1—2'耗功居中功＝P×V（PV圖上的面積）加強(qiáng)對(duì)氣缸的冷卻，省功、對(duì)氣缸潤(rùn)滑有益。二、實(shí)際工作循環(huán)（單級(jí)壓縮）1.不存在假設(shè)條件2.與理論循環(huán)不同的原因：1）余隙容積Vc的影響Vc不利的影響—?dú)埓娴臍怏w在活塞回行時(shí)，發(fā)生膨脹，使實(shí)際吸氣行程（容積）減小。Vc有利的好處—

（1）形成氣墊，利于活塞回行；（2）避免“液擊”（空氣結(jié)露）；（3）避免活塞、連桿熱膨脹，松動(dòng)發(fā)生相撞。第一節(jié)活塞式空壓機(jī)的工作原理表征Vc的參數(shù)—相對(duì)容積C、容積系數(shù)λv合適的C：低壓0.07-0.12

中壓0.09-0.14

高壓0.11-0.16

λv＝0.65—0.901）余隙容積Vc的影響C越大或壓力比越高，則λv越小。保證Vc正常的措施：余隙高度見表6-1壓鉛法—保證要求的氣缸墊厚度2.與理論循環(huán)不同的原因：二、實(shí)際工作循環(huán)（單級(jí)壓縮）第一節(jié)活塞式空壓機(jī)的工作原理2）進(jìn)排氣閥及流道阻力的影響吸氣過程壓力損失使排氣量減少程度，用壓力系數(shù)λp表示：保證措施：合適的氣閥升程及彈簧彈力、管路圓滑暢通、濾器干凈。λ