藥物誘導的麻醉

藥物誘導的麻醉第1頁，課件共22頁，創(chuàng)作于2023年2月PRINCIPLESOFTHEADMINISTRATIONOFGENERALANAESTHETICSUptakeandDistributionofinhalationalgeneralanestheticsDepthofAnesthesia-Tensionofanaestheticagentinbrain-controls-ratesofinductionandrecoveryTensionandpartialpressureareinterchangeableterms第2頁，課件共22頁，創(chuàng)作于2023年2月Tensioninthearterialbloodandbrainaresameandaredeterminedby:ConcentrationoftheanaestheticintheinspiredairdependsonrateofventilationTransferofthegasfromthealveolitothebloodDecreasedindisease(ex.emphysema)Rateoftransferisdeterminedby:Solubility(Bloodgaspartitioncoefficient.)Rateofbloodflow(directlyproportionaltotheC.O.Partialpressuresoftheagentinarterialandmixedvenousblood.Lossoftheagentfromthearterialbloodtoallthetissueofthebody第3頁，課件共22頁，創(chuàng)作于2023年2月ANAESTHESIAMACHINESAredevicesbywhichtheanesthesiologistisabletodeliverMeasuredquantitiesofanaestheticgasesandoxygenthroughaccurateflowmetersandwiththeuseofspecialvaporizersitispossibletoaddthevaporofvolatileanestheticliquidtothegasstream.ThemixtureofoxygenandanaestheticagentisthendeliveredtoabreathingcircuitforadministrationbyInhalation.第4頁，課件共22頁，創(chuàng)作于2023年2月GeneralAnestheticsarethemostdangerousdrugs

Therapeuticindexrangesbetween2-42-3timesdosecausescirculatoryfailure第5頁，課件共22頁，創(chuàng)作于2023年2月OraldosedeliversthetotaldoseWhengasorvaporisinhaledonlyasmallamountisabsorbedWhereastherestisexhaledoutinnext1-2secondsThedrugreachesthebrainbyleavingthebloodAnaestheticbloodlevelsofthesecannotbemeasuresaccuratelyConcentrationsinthelungscanbeeasilyfrequentlyandaccuratelybemeasuredThepartialspressuresoftheanaestheticinthelungandthebrainarealmostequalatequilibrium第6頁，課件共22頁，創(chuàng)作于2023年2月MinimumAlveolarConcentrationMACisthemeasureofpotencyofgeneralanestheticsItistheminimumalveolarconcentration(MAC)atoneatmosphericpressurethatproducesimmobilityin50%patientsoranimalsexposedtonoxiousstimuli第7頁，課件共22頁，創(chuàng)作于2023年2月ELIMINATIONOF

GENERALANAESTHETICSFreegasesandvaporswashoutofthelungs:Thearterialbloodtensiondeclinesfirst.Followedbythatinthetissueswheretheanaestheticagentpersistsforalongertime.Tissuehavinglowbloodflow(muscle)relievetheagentmuchslowly.OTHERROUTES:Theseagentsarealsoeliminatedinsmallerquantitiesfromskin,mucousmembraneandthekidneys第8頁，課件共22頁，創(chuàng)作于2023年2月StagesofGeneralAnaesthesia第9頁，課件共22頁，創(chuàng)作于2023年2月DEPTHOFGENERALANAESTHESIAOCCURSINSTAGESSTAGE-1ANALGESIASTAGE-2DELERIUMSTAGE-3SURGICALANESTHESIASTAGE-4MEDULLARYPARALYSES第10頁，課件共22頁，創(chuàng)作于2023年2月APPROACHESFORTESTINGDEPTHOFANAESTHESIA

Blinkingofeyelidsonstrikingtheeyelashes.SwallowingRegularityanddepthofrespiration.IncreaseinrespiratoryrateandB.P.onincisionTightnessofjawmuscles.Aboveresponsesfadeondeepeningoftheanesthesia.DeepanesthesiaLeedsto:RespiratorydepressionApneaLoweringofB.P.Asystole第11頁，課件共22頁，創(chuàng)作于2023年2月PREANAESTHETICMEDICATIONDecreaseanxietywithoutdrowsinessAmnesiaRelievepreoperativepainDecreaserequirementforaninhalationalagent.Minimisingundesirableeffectsofanesthetics.(salivation,decreaseinheartrate,coughing,vomiting)Decreasevolumeandacidityofthegastriccontents.Decreasestressresponseinpreoperativeperiod第12頁，課件共22頁，創(chuàng)作于2023年2月PREANAESTHETICMEDICATION2-3drugsareusedconcomitantly: SedativesHypnotics Antianxietydrugs Opoids Antiemetics H-2antagonists Gastrokineticagents Anticholinergics第13頁，課件共22頁，創(chuàng)作于2023年2月 DRUGSUSEDIN

PREANAESTHETICMEDICATIONSBenzodiazepines:Diazepam,Lorazepam,Midazolam.Barbibiturates:Pentobarbitone,secobarbitone.Antihistamines:Hydroxyzine,Diphenhydramine.Phenothiazines:Promethazine.Butyrophenones:Droperidol.Opoids:Morphine,fentanyl,meperidine.Anticholinergics:atropine,scopolamine,glycopyrrolate.Antiemetics:OndansetronDrugsdecreasinggastricacidity: H-2antagonists. Antacids. Gastrokineticagents.第14頁，課件共22頁，創(chuàng)作于2023年2月

MECHANISMOFACTIONSOFGENERALANAESTHETICSAlldrugsbelongtodiversegroupsInertgasesasxenonInorganic/OrganiccompdsasNitrousoxideandChloroform.ComplexOrganicMoleculesHalogenatedAlkanesandethersTheModeofactioniswithoutanysatisfactoryexplanation.POSTULATIONS:Influencesynaptictransmission.Axonalconductionisunaffected.Potentiatereleaseofinhibitoryneurotransmitters.Inhibitexcitatorysynapses.第15頁，課件共22頁，創(chuàng)作于2023年2月 MECHANISMOFACTIONSOFGENERALANAESTHETICSActionoftheseagentsisonLipidbilayerand/orproteinlipidinterfaceORIONCHANNELS(Na/K/Ca)ORLigandgatedChannelsl-Glutamate.NMDANAChRGABA-A第16頁，課件共22頁，創(chuàng)作于2023年2月Atthemolecularlevel,anestheticsprobablyexerttheireffectsbydirectinteractionswithproteinsratherthanbydisturbingthematrixofthelipidbilayerasearlierpostulated.AnestheticsMaybindtohydrophobicpocketsorclefts,producingsmallchangesinproteinConformationalertingreceptorofchannelfunction.ItisalsopossiblethatspecializedareasOfthemembranesuchastheboundarylipidssurroundingmembraneProteinsareimportantsitesofanaestheticbindingandaction. MECHANISMOFACTIONSOFGENERALANAESTHETICS第17頁，課件共22頁，創(chuàng)作于2023年2月 MECHANISMOFACTION:Theexactmechanismbywhichinhalationalanestheticsfunctionisnotknown.Thereappearstobeacorrelationbetweenanestheticpotencyandlipidsolubility(Meyer-Overtontheory),suggestingthattheseanestheticslikelyaffectthelipidmatrixofnervecellmembranesinthebrain.Furthermore,NMRandelectronspinresonancestudiesindicatethatanestheticscausealocaldisorderingofthelipidmembranematrix,possiblydecreasingthenumberofmoleculesthatalternatesimultaneouslybetweenthegelandcrystallinestates,andtherebyalteringmembranefunction.第18頁，課件共22頁，創(chuàng)作于2023年2月 NEUROLEPTANALGESIA-Stateofquiescence-Reducedmotoractivity-Reducedanxiety-Indifferencetothesurroundingswithoutlossof

consciousnessThepatientrespondstocommands.Drugs:aneuroleptcompd(Droperidol)plusanopoidanalgesic(fentanyl)Neuroleptanalgesiamaybeconvertedintoneuroleptanaesthesiabyconcominantadministrationof65%nitrousoxide第19頁，課件共22頁，創(chuàng)作于2023年2月

DISSOCIATIVEANAESTHESIAastateofsedati