Background

High-flow, heated, and humidified nasal oxygen therapy (HFNO) is frequently used in critical care and perioperative settings for a range of clinical applications. Much of the benefit of HFNO is attributed to generation of modest levels of positive airway pressure. Concern has been raised that this positive airway pressure may cause gastric insufflation, potentially increasing the risk of regurgitation and aspiration in an unprotected airway.

Methods

A prospective, interventional, assessor-blinded study was undertaken to evaluate the effects of HFNO on gastric content and gastric distension in healthy fasted adult volunteers assessed by ultrasonography. The primary outcome was the volume of gastric secretions. The secondary outcomes were the incidence of gastric air insufflation and the distribution of gastric antral grades.

Results

Sixty subjects were enrolled. No subject was found to have air gastric distension either at baseline or after treatment with HFNO. All subjects had either a Grade 0 or Grade 1 antrum, with similar distribution of antral grades and similar volume of gastric secretions before and after treatment with HFNO.

Conclusions

There was no evidence that treatment with HFNO at flow rates of up to 70 L min⁻¹ for 30 min resulted in gastric distension or an increase in gastric secretions in healthy individuals breathing spontaneously. The generalisability of these findings to subjects under anaesthesia and patients with incompetence of the lower oesophageal sphincter or impaired gastric emptying requires further investigation.

Clinical trial registration

NCT03134937.

中文翻译：

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自发通气期间，高流量的鼻氧不会增加胃分泌物的量。

背景

高流量，加热和加湿的鼻氧疗法（HFNO）经常用于重症监护和围手术期环境中，用于一系列临床应用。HFNO的大部分优点归因于适度水平的气道正压的产生。有人担心，这种气道正压会引起胃吹气，从而可能增加无保护气道中反流和误吸的风险。

方法

进行了一项前瞻性，干预性，评估者盲目的研究，以评估HFNO对健康的禁食成年志愿者的超声检查中胃内容物和胃胀的影响。主要结局是胃分泌物的量。次要结果是胃气吹的发生率和胃窦等级的分布。

结果

招募了60名受试者。在基线期或HFNO治疗后均未发现气腹胀。所有受试者均具有0级或1级胃窦，在用HFNO治疗前后，窦房间隔分布相似，胃液分泌量相似。

结论

没有证据表明，健康人自发呼吸时，HFNO的流量高达70 L min ^-1持续30 min会导致胃胀或胃分泌物增加。这些发现对麻醉下的患者和食管下括约肌功能不全或胃排空障碍的患者的普遍性需要进一步研究。

临床试验注册

NCT03134937。