比较外科医生施行经腹直肌平面阻滞与安慰剂在妇科肿瘤手术中在中线腹腔切开术后效果的双盲随机对照试验

外科医生施行的经腹直肌平面阻滞是一种现代的术后镇痛方法，该技术通过经腹膜途径在内斜肌与横直肌之间的平面内局部麻醉剂，从而靶向前外侧腹壁的感觉神经。尽管这一技术已在许多中心应用，但尚未在接受中线腹腔切开术的患者中进行前瞻性研究。本研究旨在评估外科医生施行的经腹直肌平面阻滞是否能减少术后阿片类药物需求并改善临床结局。在这项双盲、随机、安慰剂对照试验中，来自加拿大一所三级学术中心的疑似或确诊妇科恶性肿瘤的患者，在行中线腹腔切开术时被随机分配到布比卡因组（由外科医生施行40 mL 0.25%的布比卡因经腹直肌平面阻滞）或安慰剂组（由外科医生施行40 mL生理盐水经腹直肌平面阻滞），在筋膜闭合前进行。主要观察指标为术后24小时内所接受的阿片类药物总剂量（以吗啡当量计）。次要指标包括24至48小时的阿片剂量、疼痛评分、术后恶心呕吐、临床肠梗阻发生率、排气时间以及住院时间。排除标准包括对研究药物的禁忌症、慢性阿片使用史、前腹壁明显粘连阻碍注射部位访问、同时进行的非腹部手术以及计划使用神经轴麻醉或镇痛的情况。为了检测阿片需求减少20%的效果，在双侧α错误率为5%、检验力80%的条件下，计算每组需36名患者的样本量。从2020年10月至2021年11月，布比卡因组入组38例，安慰剂组入组41例。平均年龄为60岁，平均体质指数为29.3。79例中，30例（38.0%）采用脐上切口，10例（12.7%）进行了肠切除术。患者及手术特征在两组间分布均匀。布比卡因组患者术后24小时内所需的吗啡当量为98.0±59.2毫克，而安慰剂组为100.8±44.0毫克（P=0.85）。手术后4小时的平均疼痛评分为3.1±2.4（0-10评分），干预组与安慰剂组分别为3.1±2.0（P=0.93）。在干预组中，38例中有1例（2.6%）报告临床显著的恶心或呕吐，而安慰剂组中也有1例（2.4%）（P=0.95）。首次排气时间、临床肠梗阻发生率及住院天数在两组间无明显差异。对BMI<25的患者及接受脐下切口的患者进行的亚组分析也显示出类似的结果。由外科医生施行、使用布比卡因的经腹直肌平面阻滞在减少术后阿片需求及改善其他术后结局方面未显示优于安慰剂。这一结果与之前评估超声引导经腹直肌平面阻滞方法的报道不同。外科医生施行的经腹直肌平面阻滞不应作为术后多模式镇痛的标准治疗措施。

Surgeon-administered transversus abdominis plane block is a contemporary approach to providing postoperative analgesia, and this approach is performed by transperitoneally administering local anesthetic in the plane between the internal oblique and transversus abdominis muscles to target the sensory nerves of the anterolateral abdominal wall. Although this technique is used in many centers, it has not been studied prospectively in patients undergoing a midline laparotomy.This study aimed to evaluate whether surgeon-administered transversus abdominis plane block reduces postoperative opioid requirements and improves clinical outcomes.In this double-blind, randomized, placebo-controlled trial, patients with a suspected or proven gynecologic malignancy undergoing surgery through a midline laparotomy at 1 Canadian tertiary academic center were randomized to either the bupivacaine group (surgeon-administered transversus abdominis plane blocks with 40 mL of 0.25% bupivacaine) or the placebo group (surgeon-administered transversus abdominis plane blocks with 40 mL of normal saline solution) before fascial closure. The primary outcome was the total dose of opioids (in morphine milligram equivalents) received in the first 24 hours after surgery. The secondary outcomes included opioid doses between 24 and 48 hours, pain scores, postoperative nausea and vomiting, incidence of clinical ileus, time to flatus, and hospital length of stay. The exclusion criteria included contraindications to study medication, history of chronic opioid use, significant adhesions on the anterior abdominal wall preventing access to the injection site, concurrent nonabdominal surgical procedure, and the planned use of neuraxial anesthesia or analgesia. To detect a 20% decrease in opioid requirements with a 2-sided type 1 error of 5% and power of 80%, a sample size of 36 patients per group was calculated.From October 2020 to November 2021, 38 patients were randomized to the bupivacaine arm, and 41 patients were randomized to the placebo arm. The mean age was 60 years, and the mean body mass index was 29.3. A supraumbilical incision was used in 30 of 79 cases (38.0%), and bowel resection was performed in 10 of 79 cases (12.7%). Patient and surgical characteristics were evenly distributed. The patients in the bupivacaine group required 98.0±59.2 morphine milligram equivalents in the first 24 hours after surgery, whereas the patients in the placebo group required 100.8±44.0 morphine milligram equivalents (P=.85). The mean pain score at 4 hours after surgery was 3.1±2.4 (0-10 scale) in the intervention group vs 3.1±2.0 in the placebo group (P=.93). Clinically significant nausea or vomiting was reported in 1 of 38 patients (2.6%) in the intervention group vs 1 of 41 patients (2.4%) in the placebo group (P=.95). Time to first flatus, rates of clinical ileus, and length of stay were similar between groups. Subgroup analysis of patients with a body mass index of <25 and patients who received an infraumbilical incision showed similarly comparable outcomes.Surgeon-administered transversus abdominis plane block with bupivacaine was not found to be superior to the placebo intervention in reducing postoperative opioid requirements or improving other postoperative outcomes for patients undergoing a midline laparotomy. These results differed from previous reports evaluating the ultrasound-guided transversus abdominis plane block approach. Surgeon-administered transversus abdominis plane block should not be considered standard of care in postoperative multimodal analgesia.