疼痛課件：分娩鎮(zhèn)痛（英文版）完整版

LABORANALGESIALABORPAINPATHWAYSFirststage:-painisdueprimarilytouterinecontractionsthatcausestretchingandthinningoftheuterinecervix.-painimpulsestravelviavisceralafferentfibersandenterthespinalcordattheT10,T11andL1spinalsegments.-painisgenerallypoorlylocalizedandisdullorcramping.LABORPAINPATHWAYSSecondstage:-Stretchingoftheperineumproducesadditionalpain,moresomaticinnature,iswelllocalizedandsharp-theseimpulsestravelviathepudendalnervesfromtheS2,S3andS4spinalsegmentsLABORPAINTheamountofpainexperiencedbyawomanduringlaboranddeliverycanbeinfluencedbymanyfactors,includingparticipationinchildbirthpreparationclasses,parity,anduseofoxytocinANALGESIAFORLABOURPAINPsychologictechniques-hypnosis-psychoprophylaxis-positiveconditioning-patienteducation-acupuncture-trenscutaeouselectricalnervestimulationSystemicmedicationBenzodiazepines-diazepancrossestheplacentarapidly,andmaternalandfetalbloodlevelsareequalwithinminutesofanIVdoseiftotalmaternaldosageexceeds30mg,thedruganditsactivemetabolitepersistinpharmacologicalactiveconcentrationsforatleastaweekintheneonateSystemicMedicationDiazepam-theadverseeffectsinneonate:.inlargedose:hypotonia,lethargy,decreasedfeeding,andhypothermia.insmalldose:reducedbeat-to-beatvariability.

Midazolam

-ifitisusedforinduction,problemwithgenralbodytoneandbodytemperatureofneonateseen.SystemicMedicationMeperidine-peakanalgesiaeffectoccurs40to50minutesafterImand5to10minutesafterIV-thedurationis3-4hours-cancausedose-dependentneonatealdepression,asevidencedbyprolongedtimetosustainedrespiration,decreasedApgarscores,andabnomalresultsfromneurobehavioralexaminationSystemicMedicationFentanyl-50ugto100ugImand25ugIV-peakeffect(IV)3-5minandduration30-60min-Adoseof1ug/kgIvtothemotherwithin15minofcesareandeliverydidnotproduceadverseeffects-newborndruglevelswerealwayslessthanmaternallevelsSystemicMedicationMorphine-peakanalgesiceffectoccurs1-2hoursIMand20minutesIV-durationis4-6hours-inequianalgesiadoses,morphineproducesmorerespiratorydepressionofthenewbornthandosesmeperidine-morphineisreservedforearlylaborSystemicmedicationButorphanolandnabuphine

-syntheticagonist-antagonistnarcoticanalgesics-donotcauserespiratorydepressioninlaborpt-causematernaldizzinessandsomnolenceandadverseneonatalneurobehavioraleffects-rapidlycrossplacentaandincreaseFHR(causehighoutputcardiacfailure)-noadvantageoverotheropioidesSystemicMedicationKetamine-lowdoseIvketamine(10-25mg,or0.25mg/kgincrements)canbeusedwithinhaledagentstoproduceanalgesia(whichcanbeusefulduringoperateivevaginaldeliveryorcesareandelivery)SystemicmedicationInhaledanalgesia-properadministionofinhaledanalgesiabymaskinlowconcentrationstopreventlossofconsciousnessandprotectiveaiewayreflexes.-vomitingorsilentregurgitationarepossibleaspirationrisk-nitrousoxidein50%withoxygen,reliableanalgesiahasnotbeendemonstratedRegionalanesthesiaMosteffective-providepainrelief,keeppatientawakeandallowpatienttoparticipateinthelabouranddeliveryprocessUnlikelytoproducedrug-induceddepressioninthefetusormotherReducelevelsofcatecholaminesinthemother,whichmaybeneficialtofetusRegionalanesthesiaEarlyplacementofepiduralcatheterhelpscontrolbloodpressurewithgoodanalgesiaforlaborpaininpre-eclampsiapatient(afterwellhydrationandbeforecoagulopathyoccurs)ItmaybethemeanstoreducecesareansectionrateinChinaRegionalanesthesiaPatientpreparation-IV-equipmentforresuscitationandcomplication-O2,airways,laryngoscope,endotrachealtubes,suctioningapparatus,thiopenalordiazepam,ephedrineandnaloxone-preanestheticevaluation,OBplanandunderstandfetalstatus-BP,ECGandFHRand500mlIVfluidRegionalanesthesiaContraindications-absolute.patientrefusal,infectinatthesiteofneedleplacement,overtmaternalcoagulopathy,andmaternalhemodynamicinstability-relative.preexistingneurologicdisease,priorbacksurgery,isolatedcoagulationabnomalities,somecardiacdiseaseRegionalanesthesiaTimingofadministration-chestnutet.al.performedastudywhereinpatientswererandomizedtoearly(ie,1strequest0epiduralorlate(waitinguntilatleast5cmcervicaldilation).Nodifferenceincesareanrateswasfoundbetweenthetwogroupsforeitherspontaneousorinducedlabors,andthecesareanratewaslow(approximately8%)inbothRegionalanesthesiaEncourageearlyadministrationofepiduralanesthesiainlaboringwomenwithpreeclampsiaEpiduralanesthesiadidnotincreasetheincidenceofcesareandeliveryorpulmonaryedemaamonglaboringwomenwithseverehypertensivediseaseRegionalanesthesiaOneshotspinalanalgesiausingalipidsolubleopioidisrapidandsimple,butisassociatedwithalimiteddurationofactionRegionalanesthesiaEpiduralanalgesiaprovidesexcellentpainreliefandtheabilitytoextendthedurationoftheblocktomatchthedurationoflabour,butitisnot“instant“inonsetandmaybeassociatedwithmotorblockRegionalanesthesiaThecombinationofepiduralandspinalanesthesiaintoonetechnique,termed“combinedspinal-epidural’’providestheadvantagesofaspinalwiththeadditionalflexibilityofrenewalwithanepiduralcatheterRegionalanesthesiaIntrathecalnarcoticprovidesexcellentpainrelieveinstantlywithoutmotorblockCSEhasspecialbenefitifpatient’scervicaldilationisabout8cmMorethan60%ofpatientsinmyhospitalreceiveCSEanalgesianowRegionalanesthesiaIntrathecalopioids-sufentanil2.5ug-10ug-fentanyl10-25ugSideeffectsprurtus,nausea/vomiting,hypotension,urinaryretention,uterinehyperstimulationandfetaldradycardia,maternalrespiratorydepressionEpiduralanesthesiaTheblockisplacedoncethepatientisinestablishedlabor.LowdosesoflocalanesthesicsoropioidsareoftensufficientduringthefirstpartoflabortoprovideaneffectiveT10-L1segmentalblock.IncreasedlocalanestheticstocoverS2-S4forsecondsstagesoflaborEpiduralanalgesiaUsedilutelocalanestheticsandopioidsolutions(0,125%bupivacaineorropivacainewithfentanylorsufentanil)Makeeverydoseatestdose-2-3mlinitialbolus(lookforintrathecalinjection)

EpiduralanalgesiaValueofepinephrine“testdose”(15ugproduceincreasedheartrateof20-30/min)intheparturient,epinephrineproducesanindistincttachycardia,whichcanbeconfusedwithpain-inducedheartratechanges-epinephrineproducesamorereadilydetectedtachycardiaifpatientsarealreadypainfree(afterantrathecaldruginjection)EpiduralanalgesiaEpiduralopioidsforlabor-meperidine100mg-last2.5hours-fentanyl100-200ug,onset5-10min,last1-2hours-sufentanil5-15uglast1hr,40-50uglast5hr.EpiduralanalgesiaBupivacaine-longduration,lowermotorblockthanlidocaine-bewareofcardiotoxicityanddonotusetheconcentrarionof0.75%.lidocaine-mostcommonusedforcesareandeliveryEpiduralanalgesia2-chloroprocaine-estertype,fastonset,briefduration-usefultorapidlyextendalaborepiduralblockforoperativevaginal(2-3%)orcesarean(3%)delivery-adisadvantageisitapprarentantagonismofsubsequentlyinjectedepiduralopioidsandbupivacaine`EpiduralanalgesiaRopivacaineneweramidelocalanestheticssimilarinstructure,potency,andpharmacodynamicstobupivacainecardiotoxicitythatisintermediatebetweenthoseoflidocaineandbupivacaieEpiduralanalgesiaContinuousepiduralinfusion-0.04%bupivacaineplusfentanyl:almostallpatientswillrequireatleaseoneresusebolus,someneedmorethanseven-0,083%bupivacaineplussufentanil:53%requreatleastonerescue,18%needtwoormore-complication:intravascularorintrathecalinfusionEpiduralanalgesiaPatientcontrolledepiduralanalgesiaminimizedrugdosage.flexibilityandbenefitsofselfadministrationreduceddemandonprofessionaltimecontroversystillexistsregardingtheuseofacontinuousbasalinfusioninadditiontopatientcontrolledboluseswhichwouldprovideforamoreevenblockandlargerdosesEpiduralanalgesiaComplications-hypotension-convulsion-cardiacarrestdeliverthefetus,externalcardiacmassagedefibrillationepinephrinebretylium-totalspinalairway,trendelenburg,fluid,pressuresupportEpiduralanalgesiaComplicationsnerveinjuryrareepiduralhematomainfection,meningitisheadache

RegionalanesthesiaCSErapidonsetreliabilitypatientcanwalkifonlyintrathecalopiategiven(inObpatient)epinephrinetestdoseforepiduralcatheterplacementismorereliable