疼痛课件：分娩镇痛（英文版）完整版.ppt

LABOR ANALGESIA LABOR PAIN PATHWAYSFirst stage: -pain is due primarily to uterine contractions that cause stretching and thinning of the uterine cervix. -pain impulses travel via visceral afferent fibers and enter the spinal cord at the T10 ,T11 and L1spinal segments. -pain is generally poorly localized and is dull or cramping. LABOR PAIN PATHWAYSSecond stage: -Stretching of the perineum produces additional pain,more somatic in nature,is well localized and sharp - these impulses travel via the pudendal nerves from the S2,S3andS4spinal segments LABOR PAINThe amount of pain experienced by a woman during labor and delivery can be influenced by many factors,including participation in childbirth preparation classes,parity,and use of oxytocin ANALGESIA FOR LABOUR PAINPsychologic techniques -hypnosis -psychoprophylaxis -positive conditioning -patient education -acupuncture -trenscutaeous electrical nerve stimulation Systemic medicationBenzodiazepines -diazepan crosses the placenta rapidly,and maternal and fetal blood levels are equal within minutes of an IV dose if total maternal dosage exceeds 30mg, the drug and its active metabolite persist in pharmacological active concentrations for at least a week in the neonate Systemic MedicationDiazepam -the adverse effects in neonate: .in large dose: hypotonia, lethargy, decreased feeding,and hypothermia .in small dose:reduced beat-to-beat variability. Midazolam -if it is used for induction,problem with genral body tone and body temperature of neonate seen. Systemic MedicationMeperidine -peak analgesia effect occurs 40 to 50 minutes after Imand 5 to 10 minutes after IV -the duration is 3-4hours -can cause dose-dependent neonateal depression, as evidenced by prolonged time to sustained respiration,decreased Apgar scores,and abnomal results from neurobehavioral examination Systemic MedicationFentanyl -50ug to 100ug Imand 25ugIV -peak effect(IV)3-5min and dur