Background

High ventilatory frequencies increase static lung strain and possibly lung stress by shortening expiratory time, increasing intrathoracic pressure, and causing dynamic hyperinflation. We hypothesised that high intraoperative ventilatory frequencies were associated with postoperative respiratory complications.

Methods

In this retrospective hospital registry study, we analysed data from adult non-cardiothoracic surgical cases performed under general anaesthesia with mechanical ventilation at a single centre between 2005 and 2017. We assessed the association between intraoperative ventilatory frequency (categorised into four groups) and postoperative respiratory complications, defined as composite of invasive mechanical ventilation within 7 days after surgery or peripheral oxygen desaturation after extubation, using multivariable logistic regression. In a subgroup, we adjusted analyses for arterial blood gas parameters.

Results

A total of 102 632 cases were analysed. Intraoperative ventilatory frequencies ranged from a median (inter-quartile range [IQR]) of 8 (8–9) breaths min⁻¹ (Group 1) to 15 (14–18) breaths min⁻¹ (Group 4). High ventilatory frequencies were associated with higher odds of postoperative respiratory complications (adjusted odds ratio=1.26; 95% confidence interval, 1.14–1.38; P<0.001), which was confirmed in a subgroup after adjusting for arterial partial pressure of carbon dioxide and the ratio of arterial oxygen partial pressure to fractional inspired oxygen. We identified considerable variability in the use of high ventilatory frequencies attributable to individual provider preference (ranging from 22% to 88%) and temporal change; however, the association with postoperative respiratory complications remained unaffected.

Conclusions

High intraoperative ventilatory frequency was associated with increased risk of postoperative respiratory complications, and increased postoperative healthcare utilisation.

中文翻译：

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术中机械通气和术后肺部并发症的通气频率：一项医院登记研究。

背景

高通气频率会缩短呼吸时间，增加胸腔内压力并引起动态过度充气，从而增加静态肺劳损，并可能增加肺部压力。我们假设术中高通气频率与术后呼吸系统并发症有关。

方法

在这项回顾性的医院注册研究中，我们分析了2005年至2017年间在单个中心采用机械通气进行全身麻醉的成人非心动胸外科手术病例的数据。我们评估了术中通气频率（分为四组）与术后呼吸道之间的关系。并发症，定义为手术后7天内进行有创机械通气或拔管后外周血氧饱和度降低的复合物，采用多变量logistic回归分析。在一个亚组中，我们调整了对动脉血气参数的分析。

结果

共分析102 632例。术中通气频率从分8（8-9）次呼吸的中值（间四分位范围[IQR]）介于^-1（组1）到15（14-18）次呼吸分钟^-1（组4）。较高的通气频率与术后呼吸系统并发症发生几率较高相关（调整后的优势比= 1.26； 95％置信区间为1.14-1.38；P<0.001），这是在调整二氧化碳的动脉分压和动脉血氧分压与吸入氧分压之比后在一个子组中确认的。我们发现使用高通气频率存在很大差异，这可归因于个人提供者的偏爱（从22％到88％）和时间变化；然而，与术后呼吸系统并发症的关联仍然不受影响。

结论

术中高通气频率与术后呼吸系统并发症的风险增加以及术后医疗保健利用增加有关。