We thank Chen et al. [1] for their interest in our study [2], in which we found that opioid-free versus opioid-inclusive propofol anaesthesia reduced the incidence of postoperative nausea and vomiting (PONV) during the first 48-h postoperatively (5% vs. 24%; odds ratio 0.17, 95%CI 0.08–0.35; number needed to treat 5.3; p < 0.001). Opioid-free anaesthesia was also associated with a reduced need for rescue anti-emetics, lower incidences of hypotension and oxygen desaturation after tracheal extubation, and improved patient satisfaction.

Chen et al. suggest that nausea, retching and vomiting episodes should be documented and analysed separately. We defined PONV as a composite outcome including any episodes of nausea, retching or vomiting based on the literature [3]. This definition was also used in our recent study conducted in patients undergoing thoracoscopic lung surgery [4]. Few studies specified an individual occurrence of nausea, retching or vomiting as the primary outcome. We did not report the individual occurrences of PONV in our patients; however, among the secondary outcomes, the reduced PONV severity and need for rescue anti-emetics suggests that opioid-free anaesthesia alleviated PONV in patients undergoing thyroid and parathyroid surgery.

To assess the severity of PONV, we applied the PONV impact scale [3]. For opioid-free versus opioid-inclusive anaesthesia, the incidences of mild, moderate and severe PONV episodes were 5% versus 16% (p < 0.001), 1% versus 4% (p = 0.037) and 0% versus 3% (p = 0.030), respectively. The between-group differences were all statistically significant before multiple comparison corrections. In a post hoc analysis of combining moderate and severe PONV categories, we found a reduced incidence of moderate-to-severe PONV (1% vs. 7%, p < 0.001) in the opioid-free group, which remains significant even after correction for multiple comparison. Based on these data, we respectfully disagree that opioid-free propofol anaesthesia reduced only mild PONV in our patients. Moreover, we showed that patient satisfaction was higher in the opioid-free group. It is clinically meaningful that opioid-free anaesthesia improved patient comfort after thyroid and parathyroid surgery.

In terms of adverse effects, the incidence of nightmares or hallucination was 4% in the opioid-free group versus 2% in the opioid-inclusive group (odds ratio 1.78, 95%CI 0.56–5.50, p = 0.617), without a significant between-group difference. We cannot assume that more patients in the opioid-free group would experience nightmares or hallucinations. The tracheal extubation time was slightly longer (median 5 min) in the opioid-free group, while the duration of post-anaesthesia care unit stay was comparable between groups. The median dose of intra-operative propofol was 740 mg and 690 mg in the opioid-free group and opioid-inclusive group, respectively. This is a clinically insignificant difference. Hence, these results suggested that opioid-free propofol anaesthesia did not prolong recovery or increase resource utilisation in our patients. The median dose of sufentanil used in the opioid-inclusive group was 40 μg (approximately 0.6 μg.kg^-1) as per our clinical practice. This provides sufficient analgesia and is in line with doses reported in the literature [5, 6].

我们感谢陈等人。 [ 1 ] 感谢他们对我们的研究感兴趣 [ 2 ]，我们在该研究中发现，与含阿片类药物的异丙酚麻醉相比，不含阿片类药物的异丙酚麻醉可降低术后 48 小时内术​​后恶心和呕吐 (PONV) 的发生率（分别为 5% 与 1%）。 24%；比值比 0.17，95%CI 0.08–0.35；需要治疗的人数 5.3；p < 0.001）。无阿片类药物麻醉还与抢救止吐药需求的减少、气管拔管后低血压和氧饱和度降低的发生率降低以及患者满意度的提高有关。

陈等人。建议恶心、干呕和呕吐事件应单独记录和分析。我们根据文献将 PONV 定义为一种综合结果，包括任何恶心、干呕或呕吐的发作 [ 3 ]。我们最近对接受胸腔镜肺手术的患者进行的研究也使用了这个定义[ 4 ]。很少有研究将个别发生的恶心、干呕或呕吐指定为主要结局。我们没有报告患者中 PONV 的个体发生情况；然而，在次要结局中，PONV 严重程度的降低和抢救止吐药的需要表明，无阿片类药物麻醉可减轻接受甲状腺和甲状旁腺手术的患者的 PONV。

为了评估 PONV 的严重程度，我们应用了 PONV 影响量表 [ 3 ]。对于不含阿片类药物与含阿片类药物的麻醉，轻度、中度和重度 PONV 发作的发生率分别为 5% 与 16% (p < 0.001)、1% 与 4% (p = 0.037) 和 0% 与 3% (p = 0.037)。 p = 0.030），分别。在多重比较校正之前，组间差异均具有统计学显着性。在结合中度和重度 PONV 类别的事后分析中，我们发现在不含阿片类药物的组中，中度至重度 PONV 的发生率降低（1% vs. 7%，p < 0.001），即使在使用阿片类药物后，这种情况仍然显着。多重比较校正。基于这些数据，我们完全不同意无阿片类药物的丙泊酚麻醉只能减少患者轻度 PONV 的说法。此外，我们发现无阿片类药物组的患者满意度更高。无阿片类药物麻醉改善甲状腺和甲状旁腺手术后患者的舒适度具有临床意义。

就不良反应而言，无阿片类药物组的噩梦或幻觉发生率为 4%，而含阿片类药物组的噩梦或幻觉发生率为 2%（比值比 1.78，95%CI 0.56–5.50，p = 0.617），但无显着性差异。组间差异。我们不能假设无阿片类药物组中有更多患者会经历噩梦或幻觉。无阿片类药物组的气管拔管时间稍长（中位 5 分钟），而麻醉后在监护室停留的时间在各组之间相当。术中丙泊酚的中位剂量在不含阿片类药物组和含阿片类药物组中分别为740 mg和690 mg。这在临床上是微不足道的差异。因此，这些结果表明，不含阿片类药物的丙泊酚麻醉并没有延长患者的恢复时间或增加资源利用率。根据我们的临床实践，含阿片类药物组中使用的舒芬太尼的中位剂量为 40 μg（约 0.6 μg.kg ^-1 ）。这提供了足够的镇痛作用，并且与文献报道的剂量一致[ 5, 6 ]。