PURPOSE Intrathecal morphine administered during spinal anesthesia for Cesarean delivery is associated with a high incidence of postoperative nausea and vomiting (PONV). Small studies performed to date provide conflicting evidence on the effectiveness of dexamethasone as prophylaxis in this setting, raising the possibility that efficacy may be linked to dose timing. This study hypothesized that intravenous dexamethasone given prior to intrathecal morphine during spinal anesthesia may reduce the incidence of PONV. METHODS In this double-blind, placebo-controlled trial, 108 patients undergoing Cesarean delivery were randomized to receive 8 mg dexamethasone or placebo prior to spinal anesthesia that included 0.2 mg intrathecal morphine. Outcomes were assessed on postanesthesia care unit arrival, as well as at postoperative hours one, three, six, 24, and 48. The primary outcome was the total number of subjects experiencing PONV during the study period of 48 hr postpartum. Secondary outcomes included severity of pain via the numeric rating scale pain score, and the use of rescue antiemetics and analgesics. RESULTS No significant difference in the number of patients experiencing PONV was found between the treatment (n = 44, 80.0%) and control groups (n = 45, 84.9%) (difference -4.9%; 95% confidence interval, -19.2 to 9.4; P = 0.50), nor for median numeric rating scale pain scores (P = 0.24), total consumption of rescue antiemetics (P = 0.40), or opioid analgesics (P = 0.26). CONCLUSIONS This trial does not support the use of dexamethasone prior to intrathecal morphine for PONV prophylaxis in Cesarean delivery. TRIAL REGISTRATION www.clinicaltrials.gov (NCT01734161); registered 27 November, 2012.

中文翻译：

---

静脉地塞米松对鞘内注射吗啡剖宫产术后恶心和呕吐的影响：一项随机对照试验。

目的鞘内注射剖宫产术中使用鞘内注射吗啡与术后恶心和呕吐（PONV）的发生率高有关。迄今为止进行的小型研究提供了有关地塞米松在这种情况下作为预防手段的有效性的相互矛盾的证据，从而增加了将功效与给药时间挂钩的可能性。这项研究假设在脊髓麻醉期间鞘内注射吗啡之前静脉给予地塞米松可以降低PONV的发生率。方法在这项双盲，安慰剂对照试验中，将108名接受剖宫产的患者随机分组接受8 mg地塞米松或安慰剂，然后行脊髓麻醉，其中包括0.2 mg鞘内吗啡。在麻醉后护理单位到达时以及术后一，三，六，二十四，48.主要结果是在产后48小时的研究期内经历PONV的受试者总数。次要结果包括通过数字评分量表疼痛评分得出的疼痛严重程度，以及使用急救止吐药和镇痛药。结果治疗（n = 44、80.0％）与对照组（n = 45、84.9％）之间发现无PONV的患者数量无显着差异（差异为-4.9％；置信区间为95％，-19.2至9.4 ； P = 0.50），中位数字评分量表疼痛评分（P = 0.24），急救性止吐药（P = 0.40）或阿片类镇痛药的总消耗量（P = 0.26）。结论该试验不支持在鞘内注射吗啡之前使用地塞米松预防剖宫产的PONV。试验注册www.clinicaltrials.gov（NCT01734161）; 注册于11月27日，