Zhou Dawei, Li Zhimin, Zhang Shaolan, Wu Lei, Li Yiyuan, Shi Guangzhi
Department of Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
Resuscitation. 2020 Apr;149:30-38. doi: 10.1016/j.resuscitation.2020.01.036. Epub 2020 Feb 11.
Mild hypercapnia may increase cerebral oxygenation and attenuate cerebral injury in post-cardiac arrest patients. However, its association with hospital mortality has not been evaluated.
We conducted a retrospective multi-center study of prospectively collected data of all cardiac arrest patients admitted to the ICU between 2014 and 2015. Different kinds of arterial carbon dioxide tension (PaCO), including time-weighted mean PaCO, mean PaCO, admission PaCO and proportion of time spent in four PaCO categories (hypocapnia, normocapnia, mild hypercapnia, and severe hypercapnia) were used to explore the association with outcomes. Restricted cubic splines models were built to evaluate the association between PaCO and odds ratio for hospital mortality in overall population and subgroups of different pH levels (acidosis, normal pH and alkalosis).
2783 post-cardiac arrest patients in 150 ICUs were included. 933 (33.5%) were classified into the hypocapnia (PaCO < 35 mmHg), 1088 (39.1%) into the normocapnia (35-45 mmHg), 472 (17%) into the mild hypercapnia (45-55 mmHg) and 390 (10.4%) into the severe hypercapnia (>55 mmHg) group. Compared with normocapnia, mild hypercapnia was not associated with higher hospital survival probability (OR 1.08 [95% CI 0.84-1.38, p = 0.558]). Time spent in the normocapnia was associated with good outcome (OR 0.98 [95% CI 0.97-0.99, p < 0.001], for every 5 percentage point increase in time), but mild hypercapnia was not (OR 1 [95% CI 0.98-1.01, p = 0.542]). Cox-proportional hazards models supported these findings. Associations between PaCO and hospital mortality were not statistically significant in normal pH and alkalosis subgroups.
PaCO has a U-shaped association with odds ratio for hospital mortality, with mild hypercapnia not having a higher hospital survival probability than normocapnia in post-cardiac arrest patients.
轻度高碳酸血症可能会增加心脏骤停后患者的脑氧合，并减轻脑损伤。然而，其与医院死亡率的相关性尚未得到评估。
我们对2014年至2015年间入住重症监护病房（ICU）的所有心脏骤停患者的前瞻性收集数据进行了一项回顾性多中心研究。使用不同类型的动脉二氧化碳分压（PaCO），包括时间加权平均PaCO、平均PaCO、入院时PaCO以及在四个PaCO类别（低碳酸血症、正常碳酸血症、轻度高碳酸血症和重度高碳酸血症）中所花费时间的比例，来探究与预后的相关性。构建受限立方样条模型以评估总体人群以及不同pH水平（酸中毒、正常pH和碱中毒）亚组中PaCO与医院死亡率比值比之间的相关性。
纳入了150个ICU中的2783例心脏骤停后患者。933例（33.5%）被归类为低碳酸血症（PaCO＜35mmHg）组，1088例（39.1%）为正常碳酸血症（35 - 45mmHg）组，472例（17%）为轻度高碳酸血症（45 - 55mmHg）组，390例（10.4%）为重度高碳酸血症（＞55mmHg）组。与正常碳酸血症相比，轻度高碳酸血症与更高的医院生存概率无关（比值比1.08 [95%置信区间0.84 - 1.38，p = 0.558]）。在正常碳酸血症中所花费的时间与良好预后相关（比值比0.98 [95%置信区间0.97 - 0.99，p＜0.001]，时间每增加5个百分点），但轻度高碳酸血症则不然（比值比1 [95%置信区间0.98 - 1.01，p = 0.542]）。Cox比例风险模型支持了这些发现。在正常pH和碱中毒亚组中，PaCO与医院死亡率之间的相关性无统计学意义。
PaCO与医院死亡率比值比呈U形关联，在心脏骤停后患者中，轻度高碳酸血症的医院生存概率并不高于正常碳酸血症。
