The outcomes data in the adjusted cohort.

Objective Ketamine, as a sedative, has been administered during mechanical ventilation in critically ill patients; however, its impact on survival outcomes in this patient population remains uncertain. Methods This retrospective cohort study extracted data from the Medical Information Mart for Intensive Care (MIMIC-IV) database, version 3.0. Patients were categorized into the ketamine group and the control group based on whether ketamine was administered during mechanical ventilation. Propensity score matching was performed to adjust for demographic variables and coexisting conditions. The primary outcome was 28-day mortality. Secondary outcomes included 14-day and 90-day mortality rates, as well as hospital and ICU lengths of stay. Results The study included a total of 8569 patients, with 330 in the ketamine group and 8239 in the control group. After propensity score matching, significant differences in mechanical ventilation duration and the proportion of patients with acute respiratory distress syndrome remained between groups. No significant differences were observed in 28-day and 90-day mortality rates between the groups. Subgroup analysis indicated that ketamine was associated with lower 14-day mortality rates among younger patients, those with acute respiratory distress syndrome, and norepinephrine users. Ketamine administration was also found to correlate with increased lengths of stay in both the hospital and ICU. Conclusions Ketamine was more frequently selected for patients requiring prolonged mechanical ventilation. The administration of ketamine was associated with reduced 14-day but not with 28-day or 90-day mortality rates.

研究目的：氯胺酮（Ketamine）作为镇静剂，已应用于重症患者的机械通气镇静治疗，但其对该患者群体生存结局的影响仍不明确。方法：本项回顾性队列研究从重症医学信息库（Medical Information Mart for Intensive Care, MIMIC-IV）3.0版中提取数据。根据患者在机械通气期间是否使用氯胺酮，将其分为氯胺酮组与对照组。采用倾向得分匹配法校正人口学变量与合并症。主要结局指标为28天死亡率，次要结局指标包括14天、90天死亡率，以及住院时长与重症监护病房（Intensive Care Unit, ICU）停留时长。结果：本研究共纳入8569例患者，其中氯胺酮组330例，对照组8239例。倾向得分匹配后，两组间机械通气时长与急性呼吸窘迫综合征（Acute Respiratory Distress Syndrome, ARDS）患者占比仍存在显著差异。两组28天、90天死亡率无显著差异。亚组分析显示，在年轻患者、急性呼吸窘迫综合征患者以及使用去甲肾上腺素（norepinephrine）的患者中，氯胺酮与更低的14天死亡率相关。此外，氯胺酮的使用还与住院及ICU停留时长增加存在相关性。结论：氯胺酮更常被应用于需要长时间机械通气的患者。氯胺酮的使用与14天死亡率降低相关，但与28天或90天死亡率无显著关联。