目的：本研究通过对衰弱患者术中采用不同的保温措施，观察其围术期认知功能的差异性。以期揭示围术期低体温、低体温程度及平均体温等对认知功能的影响，为优化围术期体温保护、认知功能改善提供依据。

方法：纳入择期手术预计时常超过2h的衰弱患者，通过分配隐藏的区组随机法，将患者随机分为主动保温组（A组）和被动保温组（B组）。术前1天由负责入组的研究人员对患者进行认知功能检测，即完成完成简易精神状态检查（Mini-mental state examination, MMSE）及蒙特利尔认知评估（Montreal cognitive assessment, MOCA）量表评估认知水平。并于术后3日及术后7天再次填写评估量表，统计三次问卷的结果并进行分析，以此判断是否出现认知功能改变。本研究的主要结局为术后3天认知功能下降，即术后3天MOCA评分或MMSE评分与术前评分的差值＞2分；次要结局为术后7天认知功能改变，即术后7天MOCA或MMSE评分与术前评分的差值＞2分。

结果：本研究共入组484例患者。B组患者术中的平均鼻咽温显著低于A组（36.18 ± 0.54°C VS 36.44 ± 0.55°C, P<0.001）。但并未发现A组与B组在术后3天的认知功能下降的发生率上有差异（B VS A: 39.11% VS 31.03%, OR=1.43, 95%CI (0.97, 2.10), P=0.070）。同时也未发现术后7天的认知功能下降发生率上两组有显著差异（B VS A: 20.39% VS 17.07%, OR=1.71, 95%CI (0.87, 3.36), P=0.121）。

结论：总之，本研究并未证实主动保温措施较被动保温措施能有效降低衰弱患者术后认知功能下降的发生率，仍需要更大样本量、更为规范的前瞻性研究予以进一步探究。

Objective: This study aimed to investigate the impact of different intraoperative warming strategies on perioperative cognitive function in frail patients. Specifically, it sought to examine the effects of perioperative hypothermia, varying degrees of hypothermia, and average intraoperative temperature on postoperative cognitive outcomes, thereby providing evidence to optimize perioperative temperature management and cognitive function preservation.

Methods: Frail patients scheduled for elective surgery expected to last more than one hour were enrolled. Using block randomization with allocation concealment, participants were randomized into an active warming group (Group A) and a passive warming group (Group B). Cognitive function was assessed using the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) one day before surgery. These assessments were repeated on postoperative day 3 and day 7. Cognitive decline was determined by analyzing the scores from all three time points. The primary outcome was defined as postoperative cognitive decline on day 3, indicated by a decline of more than 2 points in either MoCA or MMSE score on postoperative day 3 compared to the preoperative score. The secondary outcome was cognitive decline on postoperative day 7, similarly defined as a decline of more than 2 points in either MoCA or MMSE score on postoperative day 7 compared to the preoperative score.

Results: A total of 484 patients were enrolled. The average intraoperative nasopharyngeal temperature was significantly lower in Group B compared to Group A (36.18 ± 0.54°C vs. 36.44 ± 0.55°C, P<0.001). However, no significant difference was found in the incidence of cognitive decline between groups on postoperative day 3 (Group B vs. Group A: 39.11% vs. 31.03%, OR=1.43, 95%CI (0.97, 2.10), P = 0.070) or day 7 (20.39% vs. 17.07%, OR = 1.71, 95%CI (0.87, 3.36), P = 0.121).

Conclusion: This study did not demonstrate that active warming significantly reduces the incidence of postoperative cognitive decline compared to passive warming in frail patients. Further large-scale, rigorously designed randomized controlled trials are warranted to clarify the relationship between intraoperative temperature management and cognitive outcomes in this population.