Post-Graduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul (UFRGS ), Porto Alegre, Brazil.
Chronobiol Int. 2010 Jun;27(4):865-78. doi: 10.3109/07420521003721914.
Pain exhibits temporal variations in intensity due to multiple factors, including endogenous neuroendocrine and various external influences that vary over the 24 h. Also, medications can vary in potency and/or toxicity according to the time when they are administered. However, there is no consensus among studies regarding the 24-h pattern of analgesia during labor. Taking into account the time-of-day when labor analgesia is administered, this study aimed to answer two questions: (i) Is there diurnal variation in visual analogue scale (VAS)-rated pain relief and duration of intrathecal analgesia in patients undergoing labor analgesia? (ii) If there is, what is the influence of the duration of labor on the diurnal variation of the level of pain relief and duration of intrathecal analgesia? This prospective cohort included 41 healthy, nulliparous women in the first stage of labor undergoing spinal-epidural (CSE) analgesia using fentanyl combined with bupivacaine. Subjects had an epidural catheter fitted for additional, patient-controlled analgesia (PCA) if their pain relief was unsatisfactory. The number of VAS assessments (n = 558) was divided into six time periods of the 24 h. The adjusted coefficient of determination (r(2)), the proportion of the variance explained by the association between the duration of labor and the temporal pattern of the outcomes variable, was 58% (r(2) = 0.58) for pain relief and 44% (r(2) = 0.44) for duration of intrathecal analgesia. The peak effect of labor analgesia occurred between 02:00 and 05:59 h. However, the duration of intrathecal analgesia showed two peaks, i.e., at approximately 00:00 and approximately 12:00 h. These results demonstrate that labor analgesia achieved by fentanyl combined with bupivacaine shows a diurnal pattern in pain relief and duration of spinal analgesia. However, part of these temporal patterns was explained by the association with duration of labor.
疼痛的强度会随时间变化，这是由多种因素引起的，包括内源性神经内分泌和各种随 24 小时变化的外部影响。此外，药物的效力和/或毒性也会根据给药时间而有所不同。然而，在分娩期间镇痛的 24 小时模式方面，各项研究之间并未达成共识。考虑到分娩时给予镇痛的时间，本研究旨在回答两个问题：（i）接受分娩镇痛的患者的视觉模拟评分（VAS）缓解疼痛和鞘内镇痛持续时间是否存在昼夜变化？（ii）如果存在，分娩持续时间对疼痛缓解水平和鞘内镇痛持续时间的昼夜变化有何影响？这项前瞻性队列研究纳入了 41 名健康的初产妇，她们在第一产程中接受芬太尼联合布比卡因的脊髓-硬膜外（CSE）镇痛。如果患者的疼痛缓解不满意，将为其放置硬膜外导管以进行额外的患者自控镇痛（PCA）。将 558 次 VAS 评估的次数分为 24 小时的 6 个时间段。调整后的决定系数（r(2)）表示劳动时间与结局变量时间模式之间的关联所解释的方差比例，疼痛缓解的 r(2)为 58%（r(2) = 0.58），鞘内镇痛持续时间的 r(2)为 44%（r(2) = 0.44）。分娩镇痛的峰值效应发生在 02:00 至 05:59 小时之间。然而，鞘内镇痛持续时间有两个峰值，即大约 00:00 时和大约 12:00 时。这些结果表明，芬太尼联合布比卡因的分娩镇痛在疼痛缓解和脊髓镇痛持续时间方面呈现出昼夜模式。然而，部分时间模式与分娩持续时间有关。
