Table_1_Intraoperative end-tidal carbon dioxide levels are not associated with recurrence-free survival after elective pancreatic cancer surgery: a retrospective cohort study.DOCX

BackgroundIntraoperative end-tidal carbon dioxide concentrations (EtCO2) values are associated with recurrence-free survival after colorectal cancer surgery. However, it is unknown if similar effects can be observed after other surgical procedures. There is now evidence available for target EtCO2 and its relation to surgical outcomes following pancreatic cancer surgery.
MethodsIn this single-center, retrospective cohort study, we analyzed 652 patients undergoing elective resection of pancreatic cancer at Heidelberg University Hospital between 2009 and 2016. The entire patient cohort was sorted in ascending order based on mean intraoperative EtCO2 values and then divided into two groups: the high-EtCO2 group and the low-EtCO2 group. The pre-specified primary endpoint was the assessment of recurrence-free survival up to the last known follow-up. Cardiovascular events, surgical site infections, sepsis, and reoperations during the hospital stay, as well as overall survival were pre-specified secondary outcomes.
ResultsMean EtCO2 was 33.8 mmHg ±1.1 in the low-EtCO2 group vs. 36.8 mmHg ±1.9 in the high-EtCO2 group. Median follow-up was 2.6 (Q1:1.4; Q3:4.4) years. Recurrence-free survival did not differ among the high and low-EtCO2 groups [HR = 1.043 (95% CI: 0.875–1.243), log rank test: p = 0.909]. Factors affecting the primary endpoint were studied via Cox analysis, which indicated no correlation between mean EtCO2 levels and recurrence-free survival [Coefficient −0.004, HR = 0.996 (95% CI:0.95–1.04); p = 0.871]. We did not identify any differences in the secondary endpoints, either.
ConclusionsDuring elective pancreatic cancer surgery, anesthesiologists should set EtCO2 targets for reasons other than oncological outcome until conclusive evidence from prospective, multicenter randomized controlled trials is available.

背景 术中呼气末二氧化碳浓度（end-tidal carbon dioxide concentrations, EtCO2）水平与结直肠癌术后无复发生存率相关，但目前尚不清楚该效应是否可在其他外科手术中复制。现有证据表明胰腺癌手术术中目标EtCO2水平与手术预后存在关联。
方法 本研究为单中心回顾性队列研究，纳入2009年至2016年间于海德堡大学医院接受择期胰腺癌切除术的652例患者。研究人员以术中平均EtCO2水平为依据，将全部患者队列按升序排序，并分为高EtCO2组与低EtCO2组。预先设定的主要终点为截至末次随访时的无复发生存率评估；预先设定的次要终点包括住院期间心血管事件、手术部位感染、脓毒症、再手术情况，以及总生存率。
结果 低EtCO2组患者的平均EtCO2为33.8 mmHg ±1.1，高EtCO2组为36.8 mmHg ±1.9。中位随访时间为2.6（四分位间距Q1:1.4；Q3:4.4）年。高、低EtCO2组的无复发生存率无显著差异[风险比（HR）=1.043，95%置信区间（CI）:0.875–1.243，对数秩检验：p=0.909]。通过Cox回归分析探讨影响主要终点的因素，结果显示平均EtCO2水平与无复发生存率无相关性[回归系数−0.004，HR=0.996，95%CI:0.95–1.04；p=0.871]。此外，次要终点亦未观察到组间差异。
结论 在择期胰腺癌手术中，在获得前瞻性多中心随机对照试验的确凿证据之前，麻醉医师设定EtCO2目标值时不应以肿瘤学预后为依据。