Department of Emergency and Critical Care Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan.
Department of Emergency Medicine, Asahikawa Medical University Hospital, Asahikawa, Japan.
Crit Care. 2023 Apr 1;27(1):131. doi: 10.1186/s13054-023-04407-8.
Supraphysiologic oxygen administration causes unfavorable clinical outcomes in various diseases, including traumatic brain injury, post-cardiac arrest syndrome, and acute lung injury. Accidental hypothermia is a critical illness that reduces oxygen demands, and excessive oxygen is likely to emerge. This study aimed to determine whether hyperoxia would be associated with increased mortality in patients with accidental hypothermia.
A post-hoc analysis of a nationwide multicenter prospective observational study (ICE-CRASH study) on patients with accidental hypothermia admitted in 2019-2022 was conducted. Adult patients without cardiac arrest whose core body temperature was < 32 °C and whose arterial partial pressure of oxygen (PaO) was measured at the emergency department were included. Hyperoxia was defined as a PaO level of 300 mmHg or higher, and 28-day mortality was compared between patients with and without hyperoxia before rewarming. Inverse probability weighting (IPW) analyses with propensity scores were performed to adjust patient demographics, comorbidities, etiology and severity of hypothermia, hemodynamic status and laboratories on arrival, and institution characteristics. Subgroup analyses were conducted according to age, chronic cardiopulmonary diseases, hemodynamic instability, and severity of hypothermia.
Of the 338 patients who were eligible for the study, 65 had hyperoxia before rewarming. Patients with hyperoxia had a higher 28-day mortality rate than those without (25 (39.1%) vs. 51 (19.5%); odds ratio (OR) 2.65 (95% confidence interval 1.47-4.78); p < 0.001). IPW analyses with propensity scores revealed similar results (adjusted OR 1.65 (1.14-2.38); p = 0.008). Subgroup analyses showed that hyperoxia was harmful in the elderly and those with cardiopulmonary diseases and severe hypothermia below 28 °C, whereas hyperoxia exposure had no effect on mortality in patients with hemodynamic instability on hospital arrival.
Hyperoxia with PaO levels of 300 mmHg or higher before initiating rewarming was associated with increased 28-day mortality in patients with accidental hypothermia. The amount of oxygen to administer to patients with accidental hypothermia should be carefully determined.
The ICE-CRASH study was registered at the University Hospital Medical Information Network Clinical Trial Registry on April 1, 2019 (UMIN-CTR ID, UMIN000036132).
在包括创伤性脑损伤、心搏骤停后综合征和急性肺损伤在内的各种疾病中，给予高于生理需求的氧气会导致不良的临床结局。意外低体温是一种严重的疾病，会降低氧气需求，并且可能会出现氧气过多的情况。本研究旨在确定意外低体温患者中，高氧血症是否与死亡率增加有关。
对 2019 年至 2022 年期间意外低体温患者的全国多中心前瞻性观察研究（ICE-CRASH 研究）进行了事后分析。纳入了体温<32°C 且急诊时动脉血氧分压（PaO）测量值的成年患者，无心脏骤停。高氧血症定义为 PaO 水平为 300mmHg 或更高，比较复温前高氧血症患者和无高氧血症患者的 28 天死亡率。采用倾向评分进行逆概率加权（IPW）分析，以调整患者的人口统计学特征、合并症、低体温的病因和严重程度、入院时的血流动力学状态和实验室检查以及机构特征。根据年龄、慢性心肺疾病、血流动力学不稳定和低体温严重程度进行亚组分析。
在 338 名符合条件的患者中，有 65 名患者在复温前存在高氧血症。高氧血症患者的 28 天死亡率高于无高氧血症患者（25 例（39.1%）vs. 51 例（19.5%）；优势比（OR）2.65（95%置信区间 1.47-4.78）；p<0.001）。采用倾向评分的 IPW 分析得出了类似的结果（校正 OR 1.65（1.14-2.38）；p=0.008）。亚组分析表明，高氧血症对老年人以及有心肺疾病和体温低于 28°C 的严重低体温患者有害，而在入院时血流动力学不稳定的患者中，高氧血症暴露对死亡率没有影响。
在开始复温前 PaO 水平为 300mmHg 或更高的高氧血症与意外低体温患者的 28 天死亡率增加相关。应谨慎确定给予意外低体温患者的氧气量。
ICE-CRASH 研究于 2019 年 4 月 1 日在大学医院医疗信息网临床试验注册处注册（UMIN-CTR ID，UMIN000036132）。
