Department of Anaesthesia, Pain and Perioperative Medicine, 1891Box Hill Hospital, Box Hill Hospital, Melbourne, Australia.
Department of Anaesthesiology and Perioperative Medicine, The Alfred, Melbourne, Australia.
Anaesth Intensive Care. 2021 Jul;49(4):268-274. doi: 10.1177/0310057X211024691. Epub 2021 Aug 3.
The use of high flow nasal oxygen in the care of COVID-19-positive adult patients remains an area of contention. Early guidelines have discouraged the use of high flow nasal oxygen therapy in this setting due to the risk of viral spread to healthcare workers. However, there is the need to balance the relative risks of increased aerosol generation and virus transmission to healthcare workers against the role high flow nasal oxygen has in reducing hypoxaemia when managing the airway in high-risk patients during intubation or sedation procedures. The authors of this article undertook a narrative review to present results from several recent papers. Surrogate outcome studies suggest that the risk of high flow nasal oxygen in dispersing aerosol-sized particles is probably not as great as first perceived. Smoke laser-visualisation experiments and particle counter studies suggest that the generation and dispersion of bio-aerosols via high flow nasal oxygen with flow rates up to 60 l/min is similar to standard oxygen therapies. The risk appears to be similar to oxygen supplementation via a Hudson mask at 15 l/min and significantly less than low flow nasal prong oxygen 1-5 l/min, nasal continuous positive airway pressure with ill-fitting masks, bilevel positive airway pressure, or from a coughing patient. However, given the limited safety data, we recommend a cautious approach. For intubation in the COVID-positive or suspected COVID-positive patient we support the use of high flow nasal oxygen to extend time to desaturation in the at-risk groups, which include the morbidly obese, those with predicted difficult airways and patients with significant hypoxaemia, ensuring well-fitted high flow nasal oxygen prongs with staff wearing full personal protective equipment. For sedation cases, we support the use of high flow nasal oxygen when there is an elevated risk of hypoxaemia (e.g. bariatric endoscopy or prone-positioned procedures), but recommend securing the airway with a cuffed endotracheal tube for the longer duration procedures when theatre staff remain in close proximity to the upper airway, or considering the use of a surgical mask to reduce the risk of exhaled particle dispersion.
高流量鼻氧在 COVID-19 阳性成人患者护理中的应用仍然存在争议。早期指南不鼓励在这种情况下使用高流量鼻氧疗法，因为这会增加病毒传播给医护人员的风险。然而，需要权衡增加气溶胶生成和病毒传播给医护人员的相对风险，以及高流量鼻氧在管理高危患者的气道方面的作用，以减少在插管或镇静过程中缺氧的风险。本文作者进行了叙述性综述，介绍了最近几篇论文的结果。替代结局研究表明，高流量鼻氧分散气溶胶大小颗粒的风险可能并不像最初认为的那么大。烟雾激光可视化实验和粒子计数器研究表明，高达 60 l/min 的高流量鼻氧产生和分散生物气溶胶与标准氧疗相似。风险似乎与 15 l/min 的 Hudson 面罩氧补充相似，明显低于 1-5 l/min 的低流量鼻插氧、不合规口罩的持续气道正压、双水平气道正压或咳嗽患者。然而，鉴于有限的安全数据，我们建议采取谨慎的方法。对于 COVID-19 阳性或疑似 COVID-19 阳性的患者进行插管，我们支持使用高流量鼻氧来延长高危人群的脱氧时间，包括病态肥胖、预计有困难气道的人群和严重低氧血症的患者，确保使用适配良好的高流量鼻氧插管用具，同时工作人员穿戴全套个人防护装备。对于镇静病例，我们支持在存在缺氧风险（例如肥胖症内镜检查或俯卧位手术）时使用高流量鼻氧，但建议在手术室工作人员靠近上呼吸道的时间较长的情况下，使用带套囊的气管内导管固定气道，或考虑使用外科口罩以降低呼出颗粒分散的风险。
