Feasibility of high-flow nasal oxygen therapy and two-stage sedation during endoscopic hypopharyngeal therapy

High-Flow Nasal Cannula Therapy as an Adjuvant Therapy for Respiratory Support during Endoscopic Techniques: A Narrative Review

High-flow nasal cannula (HFNC) is a respiratory support technique that delivers a controlled concentration of oxygen with high flow, heat, and humidity via the nasal pathway. As it has many physiological effects, its use has increased for a variety of clinical indications; however, there is limited guidance on using HFNC as a respiratory support tool during endoscopic procedures. We conducted a narrative review to evaluate the effect of HFNC as an adjuvant tool during fiberoptic bronchoscopy (FOB), upper gastrointestinal tract endoscopy, and surgical procedures in adults. A search of the PubMed and Cochrane databases were performed. Approximately 384 publications were retrieved, and 99 were selected (93 original works and 6 case reports with a literature review). In patients who underwent FOB, HFNC appears to be superior to conventional oxygen therapy (COT) in preventing hypoxaemia. In contrast, for gastrointestinal endoscopy, the current evidence is insufficient to recommend HFNC over COT in a cost-effective manner. Finally, in surgical procedures such as laryngeal microsurgery or thoracic surgery, HFNC has been shown to be a safe and effective alternative to orotracheal intubation. As the results are heterogeneous, we advocate for the need for more quality studies to understand the effectiveness of HFNC during endoscopic procedures.

High flow nasal oxygen, procedural sedation, and clinical governance

Procedural sedation for therapeutic and diagnostic procedures can now be achieved through deep sedation techniques that guarantee procedural success. Deep sedation techniques are delivered in a variety of non-theatre environments where the usual levels of anaesthetic equipment are not practical or economical. Hypoxic events are particularly frequent, and challenge sedation providers. Traditional low flow nasal or facial oxygen therapy techniques are often insufficient to maintain acceptable oxygen levels and prevent peri-procedural hypoxia. High flow nasal oxygen delivers warm humidified oxygen up to 70l/min, at oxygen concentrations between 21 - 100%, and reduces the incidence of hypoxic events. The provision of deep sedation is a complex process, fraught with risk, which can challenge even the skilled anaesthetist. Therefore, regulatory authorities previously stipulated that anaesthesia personnel be present during deep sedation. Changing attitudes by regulatory authorities and practical challenges providing anaesthesia specialists have led to the acknowledgement that appropriately trained non-anaesthetic staff can safely provide deep sedation. Deep sedation services are increasingly applied to subjects with complex comorbidities, sometimes excluded for safety reasons from surgery under general anaesthesia. The development of deep sedation services, delivered by non-anaesthesia personnel, to patients with complex co-morbidities requires that services implement appropriate clinical governance tools to prevent deep sedation being the wild west of anaesthesia services. Therefore, whilst high flow nasal oxygen may reduce the incidence of peri-procedural hypoxia, the introduction of clinical governance tools and the systematic introduction of initiatives to improve quality, will maintain the safety of deep sedation services.