分娩镇痛概述

Figure 1 (facing page). Sources of Pain during Labor and Maternal Physiological Responses. The pain of labor, caused by uterine contractions and cervical dilatation, is transmitted through visceral afferent (sympathetic) nerves entering the spinal cord from T10 through L1. Later in labor, perineal stretching transmits painful stimuli through the pudendal nerve and sacral nerves S2 through S4. Cortical responses to pain and anxiety during labor are complex and may be influenced by the mother’s expectations for her childbirth experience, her preparation (through education), the presence of emotional support, her age, and other factors. The perception of pain is increased by fear and anxiety. Coping behaviors may include verbalization and the need to move into various positions. She may be motivated to have a certain type of birthing experience, and these opinions will influence her judgment about pain management and other choices during labor and delivery. Maternal physiological responses to labor pain may influence maternal and fetal well-being and the progress of labor. Hyperventilation may induce hypocarbia. An increased metabolic rate increases oxygen consumption. Increases in cardiac output and vascular resistance may increase maternal blood pressure. Pain, stress, and anxiety cause release of stress hormones such as cortisol and β-endorphins. The sympathetic nervous system response to pain results in a marked increase in circulating catecholamines, such as norepinephrine and epinephrine, that can adversely affect uterine activity and uteroplacental blood flow. Effective analgesia attenuates or eliminates these responses.
妇）和0.7h（经产妇）
新的产程参考时间表
二、分娩时的疼痛来自于那里？
镇痛技术 胸段硬膜外 蛛网膜下腔 椎旁阻滞 腹下神经丛阻滞 阴部神经阻滞 宫颈旁阻滞 骶管阻滞
产程和分娩疼痛
第一产程：内脏痛，T10 - L1；第一产程晚期（宫颈扩张至7 – 10 cm）和整 个第二产程，除了内脏痛还加上了体感痛，S2-4
分娩镇痛
有关分娩镇痛的争议
ALWAYS controversial ! “Birth is a natural process” Women should suffer!! Concerns for mother’s safety Concerns for baby Concerns for effects on labor
了解一些小知识吧
一、产程和产程图
第一产程：初产妇11 - 12h，经产妇6 - 8h
潜伏期：8 - 16h，超过20h为异常 活跃期：4 - 8h
三个阶段：加速期，最大加速期和减速期
第二产程：初产妇1 - 2h，经产妇 < 1h 第三产程：5 – 15min，< 30 min
来自于八年制教材，妇产科学
Chloroform a’ la reine
The inhalation lasted fifty-three minutes. The chloroform was given on a handkerchief in fifteen minim doses; the Queen expressed herself as greatly relieved by the administration
Archbishop of Canterbury's daughter received chloroform for labor pains. He refused to criticize
1860-1940 : Dark ages of obstetric anesthesia
August Bier, Virginia Apgar 1900: Oskar Kreis , used spinal anesthesia for
1591年
Lady Euframe MacAlyane of Edinburgh, Scotland: was Burned at the Stake because asking for labor analgesia
分娩镇痛的历史
The modern era of childbirth analgesia began in 1847 when Dr J Y Simpson administered ether to a woman in childbirth, and later in the same year, chloroform
分娩疼痛到底有多严重？
A comparison of pain scores obtained through the McGill Pain Questionnaire. Scores were collected from women in labor, patients in a general hospital clinic, and patients in the emergency department after accidents involving traumatic injury. Note the modest difference in pain scores between nulliparous women with and without prepared childbirth training. PRI, Pain rating index, which represents the sum of the rank values of all the words chosen from 20 sets of pain descriptors. (Modified from Melzack R. The myth of painless childbirth [The John J. Bonica Lecture]. Pain 1984; 19:321-37.)
分娩疼痛、应激反应和激素改变
激素释放
• 交感神经：儿茶酚胺 • 肾上腺髓质：胰高血糖素；
糖异生；脂肪分解 • 垂体后叶：ADH • 垂体前叶
• ACTH：皮质醇和醛固酮
• 内啡肽 • TSH：甲状腺激素 • 生长激素；催乳激素
应激反应对血压和子宫血流的影响
分娩疼痛引起的生理、心理改变
分娩疼痛到底有好处吗？ 相信大家是一定有自己的判 断的！
Queen Victoria was given chloroform by John Snow (1853) for the birth of her 8th child Prince Leopold and this did much to popularize the use of pain relief in labor
Chloroform a’ la reine
Dr Snow gave me the blessed chloroform and the effect was soothing, quieting and delightful beyond measure
分娩镇痛的历史
1855年： Religious acceptance
Friedman曲线和张氏曲线
张氏曲线和当代数据
Friedman曲线和历史性数据 1. 潜伏期至活跃期的转折点6 cm
潜伏期至活跃期的转折点为3 – 4 cm， 2. 第一产程比历史数据更长
第二产程延长的定义初产妇 >3h，经
3. 使用硬膜外镇痛后第二产程的第 95百分位时间增加了0.8h（初产
产妇 > 2h
baseline variability periodic decelerations (due to maternal catechols?)
分娩镇痛：有哪些方法？
非药物方法
精神分析法：心理助产法，导乐分娩 经皮神经电刺激（TENS） 针刺疗法 水治疗法 经皮水注射法
药物方法
Pharmacological
Systemic Medications
Inhalational
Regional Blocks
椎管内分娩镇痛
椎管内镇痛的优点
镇痛效果最有效且最少镇静作用 阻滞深度和阻滞时间可按需调节 降低母体儿茶酚胺的浓度 改善子宫胎盘的血流 低剂量局麻药：不影响子宫的活动度 低剂量阿片类：无新生儿抑制作用
Regional Analgesia - Neonatal Effects
Uterine perfusion maintained FHR changes
相关历史
圣经故事：伊甸园
原罪（Original Sin）
God punished Eve: “In sorrow thou shalt bring forth children.” Genesis 3:16
Formed the basis of 1800 years of opposition to pain relief in labor.
分娩疼痛的来源
当宫颈扩张 2-3 cm时候，疼痛的严重 程度明显增强，此时分娩镇痛的需求 明显增加了
分娩疼痛的来源：小结
第一产程：以内脏痛为主
宫体收缩，宫颈和子宫下段扩张 钝性痛，难以精确定位 由C纤维传导（慢传导Hale Waihona Puke Baidu至T10 – L1
第二产程：以体感痛为主
盆底、阴道和会阴部的扩张和骨盆韧带牵拉 疼痛尖锐而严重，容易定位 由A纤维传导至S2 – 4
childbirth for the first time
分娩镇痛的历史
1933 : John Cleland – pain pathways 1943 : Hingson – Continuous caudal 1949 : Flowers - Continuous lumbar epidural 产科麻醉的黑暗时代在西方终于结束了！ 产科麻醉的黑暗时代在天朝仍然持续中……