Supplementary Material for: The 'Weekday effect' on Enhanced Recovery After Surgery Protocol for Gastrectomy

Introduction: While Enhanced Recovery After Surgery (ERAS) protocol demonstrated to improve outcomes after gastrectomy, some papers evidenced a detrimental effect on postoperative morbidity related to the "weekday effect". We aimed to understand whether the day of gastrectomy could affect postoperative outcomes and compliance with ERAS items. Methods: We included all patients that underwent gastrectomy for cancer between January 2017 and September 2021. Cohort was divided considering the day of surgery: Early group (Monday-Wednesday) and Late group (Thursday-Friday). Compliance with protocol and postoperative outcomes were compared. Results: 227 patients were included in Early group, while 154 in Late group. The groups were comparable in pre-operative characteristics. No significant difference in pre/intraoperative and postoperative ERAS items' compliance was apparent between Early and Late groups, with most items exceeding the 70% threshold. Median length of stay was 6.5 days and 6 days in Early and Late groups (p=0.616), respectively. Morbidity was 50% in both groups, with severe complications that occurred in 13% of Early patients and 15% of Late patients. Ninety-day mortality was 2%, and it was similar between the two groups. Conclusions: In a Center with a standardized ERAS protocol, the weekday of gastrectomy has no significant impact on the success of each ERAS item and on postoperative surgical and oncological outcomes.

引言：加速术后康复（Enhanced Recovery After Surgery, ERAS）方案已被证实可改善胃切除术患者的术后预后，但部分研究显示其存在与“工作日效应”相关的术后并发症不良影响。本研究旨在明确胃切除术的手术日期是否会对术后预后及ERAS方案依从性产生影响。方法：本研究纳入2017年1月至2021年9月期间所有因恶性肿瘤接受胃切除术的患者。根据手术日期将研究队列分为两组：早期组（周一至周三）与晚期组（周四至周五），对比两组的方案依从性及术后预后情况。结果：早期组共纳入227例患者，晚期组纳入154例患者。两组患者术前基线特征无显著差异。两组在术前、术中及术后的ERAS相关项目依从性方面均未表现出显著差异，且绝大多数项目的依从率超过70%。早期组与晚期组的中位住院时间分别为6.5天与6天（p=0.616）。两组术后并发症发生率均为50%，其中严重并发症发生率分别为13%（早期组）与15%（晚期组）。90天死亡率为2%，两组间无统计学差异。结论：在采用标准化ERAS方案的医疗中心中，胃切除术的手术工作日对各ERAS项目的依从成功率及术后外科与肿瘤学预后均无显著影响。