早期分娩镇痛对子宫肌电活动的影响

Influences of initiation of epidural analgesia pain relief in early labor on uterine myoelectrical activity

目的应用子宫肌电活动监测技术探讨产程中早期连续硬膜外自控分娩镇痛(patient-controlled epidural analgesia, PCEA)对子宫肌电活动及分娩结局的影响.方法本研究为前瞻性研究.选择2015年1月至2018年10月在广州市妇女儿童医疗中心自然临产且分娩的单胎、头位初产妇240例,将其中自愿接受分娩镇痛者随机分为早期PCEA组和晚期PCEA组,不愿意接受分娩镇痛者作为无PCEA组.早期PCEA组产妇在宫口开0~3 cm即实施PCEA;晚期PCEA组产妇宫口开3~6 cm给予PCEA;无PCEA组产妇全程无PCEA.比较产妇使用PCEA前及使用PCEA后1及2 h的视觉模拟评分(visual analogue score, VAS)及子宫肌电活动.比较各组的分娩满意度、第一产程时间、产后2 h出血量、分娩结局和新生儿Apgar评分.采用多因素方差分析、重复测量的方差分析、LSD-t检验及χ2检验进行统计学分析.结果在早期PCEA组和晚期PCEA组,PCEA后1 h VAS均低于无PCEA组[(2.08±1.34)和(2.00±1.28)与(7.65±1.04)分,LSD-t值分别为-27.713和-27.663]和同组PCEA前[分别为(7.65±0.91)和(7.62±0.86)分,LSD-t值分别为-32.879和-33.349],PCEA后2 h VAS也低于无PCEA组[(1.63±1.53)和(1.41±1.56)与(7.66±0.87)分,LSD-t值分别为-27.018和-27.823]和同组PCEA前(LSD-t值分别为-31.379和-32.718),差异均有统计学意义(P值均<0.001).早期PCEA组孕妇的分娩满意度高于晚期PCEA组[80.0%(72/90)与61.1%(55/90)],且均高于无PCEA组[20.0%(12/60)],差异均有统计学意义(P值均<0.01).3组间第一产程时间、产后2 h出血量、缩宫素使用率、中转剖宫产率、新生儿出生体重及Apgar评分差异无统计学意义(P值均>0.05).使用PCEA前以及PCEA后2 h,3组产妇子宫肌电活动各参数差异均无统计学意义(P值均>0.05).早期PCEA组产妇PCEA后1 h爆发波个数为(4.80±2.49)个、持续时间为(34.41±1.21)s、功率谱峰值频率为(0.36±0.08)Hz、均方根为(0.05±0.04)mV、总功率为(4.33±0.51)pV2,晚期PCEA组产妇PCEA后1 h爆发波个数为(5.54±3.04)个、持续时间为(36.94±1.18)s、功率谱峰值频率为(0.36±0.07)Hz、均方根为(0.05±0.05)mV、总功率为(5.36±0.59)pV2,均低于无PCEA组[分别为(9.67±2.44)个、(41.68±1.53)s、(0.48±0.05)Hz、(0.07±0.05)mV、(9.90±1.43)pV2],差异均有统计学意义(P值均<0.05).结论PCEA对子宫肌电活动的影响与实施时间无关,早期PCEA可尽快减轻产妇疼痛,提高分娩镇痛效果及满意度,母婴安全,不增加剖宫产率.

Objective To assess the influences of early implementation of patient-controlled epidural analgesia (PCEA) in labor on uterine myoelectrical activity and delivery outcomes. Methods A prospective study was conducted on 240 singleton cephalic primiparae with spontaneous labor at Guangzhou Women and Children's Medical Center from January 2015 to October 2018. Those women, who were ready to accept PCEA, were randomly assigned to early- or late-PCEA group based on cervical dilation of 0-3 cm or 3-6 cm at the time of commencing PCEA, while those who refused PCEA in labor were classified as non-PCEA group. Uterine electromyographic activity and visual analogue score (VAS) were recorded before and 1 h and 2 h after PCEA. Patient satisfaction with labor, duration of the first stage of labor, volume of postpartum bleeding within 2 h after delivery and neonatal Apgar score were compared between different groups using multivariate analysis of variance, repeated measures analysis of variance, LSD-t test or Chi-square test. Results The VAS values 1 h after PCEA in the early- and late-PCEA group were both lower than that in the non-PCEA group (2.08±1.34 and 2.00±1.28 vs 7.65±1.04, LSD-t were -27.713 and -27.663, P<0.001) and those before PCEA (7.65±0.91 and 7.62±0.86, LSD-t were -32.879 and -33.349, P<0.001). The VAS values 2 h after PCEA in the early- and late-PCEA group were both lower than that in the non-PCEA group (1.63±1.53 and 1.41±1.56 vs 7.66±0.87, LSD-t were -27.018 and -27.823, P<0.001) and those before PCEA (LSD-t were -31.379 and -32.718, P<0.001).The patient satisfaction rate with labor was higher in the early-PCEA group comparing to the late-PCEA group [80.0%(72/90) vs 61.1%(55/90), P<0.001], and the two figures above were both higher than that of the non-PCEA group [20.0%(12/60), both P<0.001]. There was no significant difference in the duration of the first stage of labor, the volume of postpartum blood loss 2 h after delivery, oxytocin usage rate, the rate of convertion to cesarean section, neonatal birth weight or Apgar score at 1 or 5 min among the three groups (all P>0.05). There was also no significant difference in uterine electromyographic parameters among the three groups before or 2 h after PCEA (all P>0.05). The number and duration of burst, power density spectrum peak frequency, root mean square and total power 1 h after PCEA in the early- and later-PCEA group were all lower than those in the non-PCEA group [4.80±2.49 and 5.54±3.04 vs 9.67±2.44;(34.41±1.21) and (36.94±1.18) vs (41.68±1.53) s;(0.36±0.08) and (0.36±0.07) vs (0.48±0.05) Hz;(0.05±0.04) and (0.05±0.05) vs (0.07±0.05) mV;(4.33±0.51) and (5.36 ±0.59) vs (9.90±1.43) pV2;all P<0.05]. Conclusions The effect of PCEA on uterine myoelectrical activity has no association with the commencing time. While early PCEA could alleviate the labor pain as soon as possible, which enable us to improve the efficacy of labor analgesia, patient satisfaction and maternal and neonatal safety without increasing cesarean section rate.