【原】术中低二氧化碳=更安全？ 新研究揭示麻醉管理的潜在风险！

术中低二氧化碳=更安全？

新研究揭示麻醉管理的潜在风险！

导语：

"术中维持低呼气末二氧化碳（etCO₂）能减少并发症？"这一传统观念正被最新研究颠覆！一项覆盖29国、纳入近2500例患者的大型研究发现，术中低etCO₂患者术后严重肺部并发症风险竟高出近一倍！麻醉医生该如何看待这一指标？让我们一探究竟！

论文摘要

Background:

Patients receiving intraoperative ventilation during general anesthesia often have low end–tidal CO2 (etCO2). We examined the association of intraoperative etCO2 levels with the occurrence of postoperative pulmonary complications (PPCs) in a conveniently–sized international, prospective study named 'Local ASsessment of Ventilatory management during General Anesthesia for Surgery’ (LAS VEGAS). 

背景：在接受全身麻醉手术的患者中，术中呼气末二氧化碳（etCO₂）水平常偏低。我们旨在通过一项名为“局部评估术中通气管理（LAS VEGAS）”的国际前瞻性观察性研究，探讨术中etCO₂水平与术后肺部并发症（PPCs）发生率的关联。

Methods: 

Patients at high risk of PPCs were categorized as 'low etCO2’ or 'normal to high etCO2’ patients, using a cut–off of 35 mmHg. The primary endpoint was a composite of previously defined PPCs; the individual PPCs served as secondary endpoints. The need for unplanned oxygen was defined as mild PPCs and severe PPCs included pneumonia, respiratory failure, acute respiratory distress syndrome, barotrauma, and new invasive ventilation. We performed propensity score matching and LOESS regression to evaluate the relationship between the lowest etCO2 and PPCs. 

方法：将高风险PPCs患者分为“低etCO₂组”（<35 mmHg）和“正常/高etCO₂组”（≥35 mmHg）。主要终点为复合PPCs发生率，次要终点为单个PPCs事件。通过倾向性评分匹配和局部估计散点平滑回归（LOESS）分析etCO₂水平与结局的关系。

Results: 

The analysis included 1843 (74 %) 'low etCO2’ patients and 648 (26 %) 'normal to high etCO2’ patients. There was no difference in the occurrence of PPCs between 'low etCO2’ and 'normal to high etCO2’ patients (20 % vs. 19 %; RR 1.00 [95 %–confidence interval 0.94 to 1.06]; P = 0.84). The proportion of severe PPCs among total occurring PPCs, were higher in 'low etCO2’ patients compared to 'normal to high etCO2’ patients (35 % vs. 18 %; RR 1.16 [1.08 to 1.25]; P < 0.001). Propensity score matching did not change these findings. LOESS plot showed an inverse relationship of intraoperative etCO2 levels with the occurrence of PPCs. 

结果：分析纳入1843例低etCO₂患者和648例正常/高etCO₂患者。两组PPC总体发生率无显著差异（20% vs. 19%，RR 1.00，95%CI 0.94-1.06，P=0.84），但低etCO₂组严重PPCs发生率更高（35% vs. 18%，RR 1.16，95%CI 1.08-1.25，P<0.001）。倾向性评分匹配后结果一致，LOESS回归显示etCO₂水平与PPCs呈负相关。

Conclusions: 

In this cohort of patients at high risk of PPCs, the overall occurrence of PPCs was not different between 'low etCO2’ patients and 'normal to high etCO2’ patients, but severe PPCs occurred more often in 'low etCO2’, with an inverse dose–dependent relationship between intraoperative etCO2 levels and PPCs. 

结论：在本研究中，低etCO₂与正常/高etCO₂患者的PPC总体发生率相似，但低etCO₂患者更易发生严重PPCs，且存在剂量-反应关系。未来需进一步研究低etCO₂与严重PPCs的因果关系。

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关键术语说明

 etCO₂：呼气末二氧化碳（End-tidal Carbon Dioxide）

· PPCs：术后肺部并发症（Postoperative Pulmonary Complications）

· 倾向性评分匹配：Propensity Score Matching（用于控制混杂变量）

· LOESS回归：局部估计散点平滑回归（一种非参数平滑方法）

结果展示

关键术语说明

 etCO₂：呼气末二氧化碳（End-tidal Carbon Dioxide）

· PPCs：术后肺部并发症（Postoperative Pulmonary Complications）

· 倾向性评分匹配：Propensity Score Matching（用于控制混杂变量）

· LOESS回归：局部估计散点平滑回归（一种非参数平滑方法）

表1 病人特征

表2 非匹配队列中的通气特征

表3 非匹配队列中的结局

图1 两组肺部并发症对比

图 2 非匹配队列中总体PPCs发生率与最低etCO₂的相关性

图4轻度/严重PPCs与etCO₂的相关性

1-s2.0-S0952818024003581-main.pdf

文章：苗苗

排版：肉肉