摘要目的 比较硬膜外分娩镇痛始于潜伏期与活跃期对母婴的影响.方法 自愿接受分娩镇痛的足月、单胎、头位初产妇80例,根据开始分娩镇痛的时机分为潜伏期(宫口扩张0.5～3.0 cm)组(L组,n=40)和活跃期(宫口扩张＞3.0 cm)组(A组,n=40).同时随机选取不接受分娩镇痛的足月、单胎、头位初产妇40例为对照组(C组).A组和L组均以L2,3间隙进行硬膜外穿刺,以0.1%罗哌卡因+芬太尼(2 μg/ml)5 ml为试验剂量,随后注入上述药物10 ml,硬膜外导管连接镇痛泵,药物同上,采用PCA模式,PCA量6 ml,间隔时间30 min.于镇痛前即刻(C组于宫口扩张3 cm时)、镇痛开始后5、10、15、30 min、宫口扩张7～8 cm及10 cm时行VAS评分,采用改良Bromage评分法测定下肢肌力.镇痛前取静脉血样,胎儿娩出即刻取母体静脉血样及脐带血样,采用放免法测定血浆皮质醇浓度,采用高效液相色谱法测定脐带血浆罗哌卡因浓度.记录镇痛时间、产程时间、分娩方式、催产素使用情况、药物用量、胎儿娩出后1、5 min时Apgar评分、产妇满意度评分及不良反应发生情况.结果 与C组比较,L组和A组镇痛开始后各时点VAS评分降低,胎儿娩出即刻母体血浆皮质醇浓度降低,第一产程时间缩短,催产素使用率升高,剖宫产率降低(P＜0.05),其余指标差异无统计学意义(P＞0.05).与L组比较,A组镇痛时间缩短(P＜0.05),其余指标差异无统计学意义(P＞0.05).3组间脐带血浆皮质醇浓度比较差异无统计学意义(P＞0.05).结论 硬膜外分娩镇痛始于潜伏期与活跃期均能降低剖宫产机率,在其程度上无差异,且不延长产程,对新生儿同样安全.

abstractsObjective To compare the effects of labor epidural analgesia initiated in latent phase and active phase on parturients and neonates. Methods One hundred twenty nulliparous women at full term (single, head presentation, ASA Ⅰ or Ⅱ ) were randomly divided into 3 groups (n=40 each):control group(group C) ; PCEA initiated in latent phase group (cervical dilatation 0.5-3.0 cm) (group L) and PCEA initiated in active phase group (cervical dilatation＞3.0 cm) (group A). Epidural catheter was placed through L2,3 interspace. 0.1% ropivacaine with fentanyl 2 μg/ml was used for PCEA. A test dose of 5 ml was followed by a loading dose of 10 ml. PCEA device was programmed to allow a bolus of 6 ml with a 30 min lockout interval. The intensity of pain was measured with VAS (0=no pain, 10=worst pain) before analgesia, at 5, 10, 15 and 30 min after beginning of PCEA and cervical dilatation of 7-8 cm and 10 cm. Degree of motor block was assessed by lower extremity muscle strength (modified Bromage scale,0=no motor block, 3=inability to flex ankle joints).Plasma cortisol in maternal venous blood obtained before analgesia and at delivery of fetus and in umbilical cord blood and plasma ropivacaine concentrations in umbilical core blood were determined.The length of every stage, duration of analgesia,delivery mode, the amount of oxytocin used, maternal satisfaction, Apgar scores of the neonates and adverse effects were recorded. Results PCEA initiated in latent phase or active phase significantly reduced VAS score, the plasma cortisol level at delivery, the duration of 1st stage of labor, and the rate of cesarean section and increased the use of oxytocin in L and A groups as compared with group C, but there was no significant difference in the above variables between L and A groups. The duration of analgesia was shorter in group A than in group L. Conclusions Labor epidural analgesia initiated in latent phase or active phase can decrease the rate of cesarean section but does not prolong the duration of labor and is safe for the newborn.