Department of Anesthesiology, University of Michigan Medical School, 1500 E. Medical Center Dr., UH 1H247, Ann Arbor, MI, 48105, USA.
Can J Anaesth. 2022 Jan;69(1):106-118. doi: 10.1007/s12630-021-02118-8. Epub 2021 Oct 6.
The difference between arterial and end-tidal partial pressure of carbon dioxide (ΔCO) is a measure of alveolar dead space, commonly evaluated intraoperatively. Given its relationship to ventilation and perfusion, ΔCO may provide prognostic information and guide clinical decisions. We hypothesized that higher ΔCO values are associated with occurrence of a composite outcome of re-intubation, postoperative mechanical ventilation, or 30-day mortality in patients undergoing non-cardiac surgery.
We conducted a historical cohort study of adult patients undergoing non-cardiac surgery with an arterial line at a single tertiary care medical centre. The composite outcome, identified from electronic health records, was re-intubation, postoperative mechanical ventilation, or 30-day mortality. Student's t test and Chi-squared test were used for univariable analysis. Logistic regression was used for multivariable analysis of the relationship of ΔCO with the composite outcome.
A total of 19,425 patients were included in the final study population. Univariable analysis showed an association between higher mean (standard deviation [SD]) intraoperative ΔCO values and the composite outcome (6.1 [5.3] vs 5.7 [4.5] mm Hg; P = 0.002). After adjusting for baseline subject characteristics, every 5-mm Hg increase in the ΔCO was associated with a nearly 20% increased odds of the composite outcome (odds ratio, 1.20; 95% confidence interval, 1.12 to 1.28; P < 0.001).
In this patient population, increased intraoperative ΔCO was associated with an increased odds of the composite outcome of postoperative mechanical ventilation, re-intubation, or 30-day mortality that was independent of its relationship with pre-existing pulmonary disease. Future studies are needed to determine if ΔCO can be used to guide patient management and improve patient outcomes.
动脉与呼气末二氧化碳分压之差（ΔCO）是衡量肺泡死腔的指标，通常在术中进行评估。鉴于其与通气和灌注的关系，ΔCO 可能提供预后信息并指导临床决策。我们假设在接受非心脏手术的患者中，较高的 ΔCO 值与再插管、术后机械通气或 30 天死亡率的复合结局的发生有关。
我们对在一家三级医疗中心接受非心脏手术并置有动脉导管的成年患者进行了一项回顾性队列研究。复合结局通过电子病历确定，包括再插管、术后机械通气或 30 天死亡率。采用 Student's t 检验和卡方检验进行单变量分析。采用逻辑回归分析 ΔCO 与复合结局的关系。
共有 19425 例患者纳入最终的研究人群。单变量分析显示，较高的术中平均（标准差）ΔCO 值与复合结局之间存在关联（6.1 [5.3] 与 5.7 [4.5] mm Hg；P = 0.002）。在校正基线患者特征后，ΔCO 每增加 5mmHg，复合结局的发生几率增加近 20%（优势比，1.20；95%置信区间，1.12 至 1.28；P < 0.001）。
在该患者人群中，术中 ΔCO 增加与术后机械通气、再插管或 30 天死亡率的复合结局发生几率增加相关，这与其与既往肺部疾病的关系无关。需要进一步研究来确定 ΔCO 是否可用于指导患者管理并改善患者结局。
