OBJECTIVE: 

To compare pain scores during office dilation and aspiration between low-volume and high-volume paracervical block of the same dose.

METHODS: 

We conducted a multi-site, randomized, single-blind, placebo-controlled trial from October 2018 to December 2020. We randomized participants presenting for office dilation and aspiration under minimal sedation stratified by procedural indication (induced abortion vs early pregnancy loss) to a 20-mL buffered 1% lidocaine paracervical block or a 40-mL buffered 0.5% lidocaine paracervical block, both with two units of vasopressin in a standardized technique. To detect a 15-mm or greater difference in pain at the time of cervical dilation with 80% power and a two-sided alpha of 0.05, a total of 104 participants was required. The study was also powered to detect a 20-mm or greater difference in pain at the time of cervical dilation within each stratum (induced abortion and early pregnancy loss). The primary outcome was pain with cervical dilation on a 100-mm visual analog scale in the overall cohort. Secondary outcomes included pain with cervical dilation within each stratum. We used a Wilcoxon rank-sum test to compare median pain scores between groups.

RESULTS: 

We enrolled 114 participants. There was no difference in median pain scores between low-volume and high-volume groups during dilation (62 mm vs 59 mm, P=.94), aspiration (69.5 mm vs 70 mm, P=.47), postprocedure (25 mm vs 25 mm, P=.76), or overall (60 mm vs 60 mm, P=.23). Stratified by indication, there were no significant differences in scores at any time point between the low-volume and high-volume paracervical block groups. There was decreased overall pain in patients with induced abortion who received the higher volume paracervical block, though this did not reach statistical significance (67.5 mm vs 60.5 mm, P=.08). Pain during paracervical block administration was similar between groups (55 mm vs 45 mm, P=.24) and there was no difference in occurrence of side effects (P=.63).

CONCLUSION: 

We found no difference in pain with cervical dilation among participants who received the low-volume compared with high-volume paracervical block when studied alone.

CLINICAL TRIAL REGISTRATION: 

ClinicalTrials.gov, NCT03636451.

中文翻译：

---

宫颈旁阻滞体积对扩张和抽吸疼痛控制的影响：一项随机对照试验

客观的： 

比较相同剂量的低容量和高容量宫颈旁阻滞在办公室扩张和抽吸期间的疼痛评分。

方法： 

我们在 2018 年 10 月至 2020 年 12 月期间进行了一项多中心、随机、单盲、安慰剂对照试验。我们将根据程序指征（人工流产与早期妊娠丢失）分层的最小镇静下进行办公室扩张和抽吸的参与者随机分配到20 mL 缓冲 1% 利多卡因宫颈旁阻滞或 40 mL 缓冲 0.5% 利多卡因宫颈旁阻滞，均采用标准化技术使用两个单位的加压素。为了以 80% 的功效和 0.05 的两侧 α 值检测宫颈扩张时 15 毫米或更大的疼痛差异，总共需要 104 名参与者。该研究还有助于检测每个层内宫颈扩张时 20 毫米或更大的疼痛差异（人工流产和早期妊娠丢失）。主要结果是整个队列中 100 毫米视觉模拟量表的宫颈扩张疼痛。次要结果包括每个层内的宫颈扩张疼痛。我们使用 Wilcoxon 秩和检验来比较各组之间的中位疼痛评分。

结果： 

我们招募了 114 名参与者。在扩张（62 mm vs 59 mm， P =.94）、抽吸（69.5 mm vs 70 mm，P =.47）、术后（25 mm）期间，低容量组和高容量组的中位疼痛评分没有差异与 25 毫米相比，P =.76），或整体（60 毫米与 60 毫米，P =.23）。按适应症分层，低容量和高容量宫颈旁阻滞组在任何时间点的评分均无显着差异。接受较大量宫颈旁阻滞的人工流产患者的总体疼痛有所减轻，尽管这没有达到统计学意义（67.5 mm vs 60.5 mm，P=.08)。宫颈旁阻滞给药期间的疼痛在各组之间相似（55 mm vs 45 mm，P =.24），并且副作用发生率没有差异（P =.63）。

结论： 

我们发现单独研究时，接受低容量与高容量宫颈旁阻滞的参与者的宫颈扩张疼痛没有差异。

临床试验注册： 

ClinicalTrials.gov，NCT03636451。