术后肺部并发症的原因

摘要译文（供参考）

ENIGMA II试验中的术后肺部并发症：

事后分析

背景：

高吸入浓度的氧化亚氮增加通气不良肺段的吸收性肺不张的发生。

麻醉气体混合物中氧化亚氮的评估（ENIGMA）试验发现，与不含氧化亚氮时吸入80%氧气相比，在大手术中使用氧化亚氮麻醉时，术后肺部并发症和伤口脓毒症的发生率更高。

更大的ENIGMA II试验将患者随机分配到吸入30%氧气的氧化亚氮组或空气组中，但发现对伤口感染或败血症发生率没有影响。

然而，未测量术后肺部并发症。

在目前的研究中，收集了事后数据，以确定在澳大利亚ENIGMA II队列中招募的患者中，氧化亚氮是否会导致肺不张和肺炎发病率升高。

方法：

对在澳大利亚10家医院参加试验的患者的数字健康记录进行了检查，并对试验治疗分配进行了盲查。

主要终点是肺不张的发生率，在胸部放射学中被确诊为肺不张或塌陷。

肺炎作为次要终点，需要有发热、白细胞增多或痰培养阳性，及胸部放射学诊断报告。

使用卡方检验，根据治疗措施对氧化亚氮组和无氧化亚氮组进行比较。

结果：

最终数据集中包括2328名随机患者的数据。

两个治疗组在ENIGMA II的手术类型和持续时间、危险因素和围手术期管理方面相似。

氧化亚氮导致肺不张的发生率降低19.3%（1169例中171例[14.6%]，1159例中210例[118.1%]；比值比0.77；95%可信区间0.62至0.97；P=0.023）。

肺炎发生率无差异（1169年中60例[5.1%]，而1159年中52例[4.5%]，比值比1.15；95%CI 0.77至1.72；P=0.067）

或合并肺部并发症（比值比0.84；95%CI 0.69至1.03；P=0.093）

结论：

与早期的ENIGMA试验相比，ENIGMA II试验中的一氧化二氮麻醉与大手术后肺不张的发生率较低有关，但与肺炎无关。

原文摘要

Postoperative Pulmonary Complications in the ENIGMA II Trial: 

A Post Hoc Analysis

Background: 

Nitrous oxide promotes absorption atelectasis in poorly ventilated lung segments at high inspired concentrations. 

The Evaluation of Nitrous oxide In the Gas Mixture for Anesthesia (ENIGMA) trial found a higher incidence of postoperative pulmonary complications and wound sepsis with nitrous oxide anesthesia in major surgery compared to a fraction of inspired oxygen of 0.8 without nitrous oxide. 

The larger ENIGMA II trial randomized patients to nitrous oxide or air at a fraction of inspired oxygen of 0.3 but found no effect on wound infection or sepsis. 

However, postoperative pulmonary complications were not measured. In the current study, post hoc data were collected to determine whether atelectasis and pneumonia incidences were higher with nitrous oxide in patients who were recruited to the Australian cohort of ENIGMA II.

Methods: 

Digital health records of patients who participated in the trial at 10 Australian hospitals were examined blinded to trial treatment allocation. 

The primary endpoint was the incidence of atelectasis, defined as lung atelectasis or collapse reported on chest radiology. 

Pneumonia, as a secondary endpoint, required a diagnostic chest radiology report with fever, leukocytosis, or positive sputum culture. 

Comparison of the nitrous oxide and nitrous oxide-free groups was done according to intention to treat using chi-square tests.

Results: 

Data from 2,328 randomized patients were included in the final data set. 

The two treatment groups were similar in surgical type and duration, risk factors, and perioperative management recorded for ENIGMA II.

There was a 19.3% lower incidence of atelectasis with nitrous oxide (171 of 1,169 [14.6%] vs. 210 of 1,159 [18.1%]; odds ratio, 0.77; 95% CI, 0.62 to 0.97; P = 0.023). 

There was no difference in pneumonia incidence (60 of 1,169 [5.1%] vs. 52 of 1159 [4.5%]; odds ratio, 1.15; 95% CI, 0.77 to 1.72; P = 0.467) or combined pulmonary complications (odds ratio, 0.84; 95% CI, 0.69 to 1.03; P = 0.093).

Conclusions: 

In contrast to the earlier ENIGMA trial, nitrous oxide anesthesia in the ENIGMA II trial was associated with a lower incidence of lung atelectasis, but not pneumonia, after major surgery.

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校对：Michel.米萱