新生儿呼吸生理广州

新生儿呼吸生理特点,孙波复旦大学附属儿科医院,新生儿肺功能监测,气血交换:肺通气,肺换气呼吸力学，肺泡上皮细胞生物学呼吸肌，能量代谢呼吸中枢与化学感受器反馈性调节液体吸收平衡,10,20,30,3,6,9,weeks,Birth,months,肺发育阶段,AC:4weeksDE:5weeksF:6weeksG:8weeks,胎儿肺泡面积增加与肺容量增加成正比,肺小叶(肺泡腺囊)呼吸功能单位,肺泡上皮细胞I型,II型,毛细血管网,气道：气管、支气管、小支气管、细支气管、呼吸性细支气管,血管：肺动脉、肺静脉呼吸中枢：延髓，呼吸神经元，交感、副交感神经，膈神经,胸廓和呼吸肌,膈肌：食道大动脉下腔静脉上面：肺底心包下面：肝脏,呼吸道的防御机制和肺的代谢功能,大气道：假复层纤毛上皮小气道：免疫球蛋白IgA肺泡：巨噬细胞表面活性物质的分泌血管紧张素II转换酶,LungDevelopment,Fromweek22ofgestationpulmonarygasexchangebecomestheoreticallypossible,新生儿肺功能监测,气血交换:肺通气,肺换气呼吸力学，肺泡上皮细胞生物学呼吸肌，能量代谢呼吸中枢与化学感受器反馈性调节液体吸收平衡,新生儿肺功能监测,AlveolarVentilation肺泡通气,GasExchangeVolumeTheportionofeachbreaththatisavailableforgasexchange.OptimizingAlveolarMinuteVentilationprovidesthemosteffectiveCO2removal.,AlveolarVentilation,通气-灌流比例,通气-灌流比例适当？合适的通气量？1潮气2频率3肺泡通气4通气-灌流5循环-灌流6组织利用,FetalCirculationandPlacenta,Upperbody,Ductusarteriosus,Pulmonaryartery,Foramenovale,Ductusvenosus,Liver,Umbilicalcord,Lowerbody,Placenta,新生儿呼吸参数,频率：30-40次/分钟潮气量：6-8mL/kg吸气时间：0.3-0.5s死腔：2mL/kg功能余气量：25-30mL/kg残余气量：10-15mL/kg,新生儿血气参数,pH7.35-7.45PaCO25-7kPa(35-50mmHg)PaO28-12kPa(60-90mmHg)SaO290-100%HCO320-27mmol/LBE-5.0-5.0mmol/L,呼吸机吸气时间延长,ApplicationofLungFunctionParametersDetectionofLungOverdistention,IdentifyingLungOverdistentionDuringMechanicalVentilationbyUsingVolume-PressureLoopsFisher/Mammel/Coleman/Bing/Boros:PedPulmonol:5:10-14(1988)V-PNormalOverdistendedPvalueC(ml/cmH2O)0.51?0.370.75?0.50-C20(ml/cmH2O)1.08?1.130.46?0.32-C20/C1.93?0.910.63?0.1195%90可再利用,肺表面活性物质的应用,气道滴入50-200毫克/公斤，间隔6-12小时新生儿呼吸窘迫综合征RDS(确定)胎粪吸入综合征肺炎呼吸衰竭急性肺损伤、ARDS开胸和肺移植手术后呼吸衰竭,药促PS合成分泌,产前糖皮质激素促进肺组织成熟出生后糖皮质激素促进肺液吸收机械通气牵张肺泡促进内源性PS合成外源性PSPS合成底物,管状髓样物，晶格网状Tubularmyelin,磷脂和蛋白相互作用,饱和磷脂：降低最小表面张力不饱和磷脂：降低最大表面张力疏水性蛋白：SP-B维持磷脂膜构象SP-C聚合磷脂，调节磷脂膜构象亲水性蛋白：SP-A调节磷脂代谢，强化磷脂膜；SP-D不清,对功能余气量的影响,提高功能余气量，提高顺应性需要维持PEEP在适当水平，以提高药物疗效可以和CPAP联合应用，减少气道插管和机械通气,对脑血流的影响,可能使脑血流下降：通过增加肺血流和动脉导管分流通过循环二氧化碳下降,对肺血流的影响,降低肺动脉压，增加肺血流改善通气-灌流与吸入一氧化氮联合应用有协同作用,长期随访,使PDA增加不增加神经运动发育障碍不增加慢性肺病没有医源性感染没有动物源蛋白致免疫反应,MeconiumAspirationSyndrome,Hypoxia-pO2,CompensatorymechanismsCentralizationofbloodflowtothebrainandheartVasodilationinbrainandheartIncreasedextractionofoxygenHypoxialeadstoOrganfailureMultipleorganfailureBraindamageThenaturalcompensatorymechanismsmaybereducedintheprematurenewborn,HyperoxiaandCerebralBloodFlow,Cerebralbloodflowvelocity(cm/s),Normaloxygenation,Hyperoxia,Normaloxygenation,CerebralBloodFlowandpCO2,CBFversuspCO2in18spontaneouslybreathingpreterminfantsinvestigated2and3hoursafterbirth,Hypocapnia-pCO2,pCO2leadstoReductionofbloodflowtothebrainReductionofoxygensupplytothebrainIncreasedriskofbraindamage,Hypercapnia-pCO2,pCO2leadstoIncreasedbloodflowIncreasedriskofintracranialbleeding,OddsRatios*foranAdverseOutcomeAssociatedWithMax.LowpCO2MeasurementsDuringtheFirstThreeDaysofLifein192MechanicallyVentilatedPretermInfants,pCO2Changes,pCO2maychangewithinminutes,withimmediateeffectonthecerebralbloodflow12%per7.5mmHg,0-24hoursafterbirth30%per7.5mmHg,24hoursafterbirthSuddenchanges,evenminorand/orwithinreferencerange:IncreasedriskofbraindamageImmediateinterventionneededGradualchangesNotassevere,butobservationneeded,LungFunctionMonitoringC20/CRatio,OverdistentioncanleadtovolutraumaandincreasedpulmonaryvascularresistanceTodecreaseoverdistention,decreasePIPinPLV*orVtinVLV*OptimizePEEPlevel:excessivelevelofPEEPmightleadtooverdistention,PV-Loop,Volume,Pressure,Overdistention,begins,C20,ClinicalSignificance,VolumeOverdistention,*PLV=PressureLimitedVentilation*VLV=VolumeLimitedVentilation,C,Peep,ApplicationofLungFunctionMonitoringDetectionofLungOverdistention,IdentifyingLungOverdistentionDuringMechanicalVentilationbyUsingVolume-PressureLoopsFisher/Mammel/Coleman/Bing/Boros:PedPulmonol:5:10-14(1988).Inconclusion,V-Ploopscanprovideusefulinformationregardingtheinteractionoflungsandmechanicalventilator.Lungoverdistentionmaybeidentifiedbeforelungruptureoccurs.TheC20/CratioquantifiessuchV-Ploopevidenceoflungoverdisten-tionduringne