Maintaining oxygenation during awake fibre-optic intubation—the role of high flow nasal oxygen therapy: a narrative review

Introduction

Awake fibre-optic intubation (AFOI) remains a crucial tool for the airway manager in cases where other approaches to the airway are likely to fail or be complicated by airway obstruction due to anaesthetic drugs. While the approach is currently used in a minority of patients, its use is greater in centres specialising in patients with head and neck pathology (1,2). It is generally used in patients with the most challenging anatomy. Since its first use in 1967, the technique has undergone progressive refinement, particularly in the area of sedation, which is almost ubiquitous when performing this procedure, as it improves patient tolerance of awake intubation and increases the chances of success (3). Among the most common and dangerous aspects of AFOI is the development of hypoxemia as a direct consequence of the procedure or as an adverse effect of sedation (4,5). The development of hypoxemia can be reduced by administering supplemental oxygen (1). However, there is no standardised approach to oxygen supplementation, and consequently, the techniques and equipment used by airway managers are highly varied. This narrative review aims to summarise existing knowledge in this area regarding the incidence of hypoxemia with various oxygenation techniques and to compare the effectiveness of available technologies, with a special focus on high-flow nasal cannula (HFNC). There have been several systematic reviews for oxygenation techniques during procedural sedation and gastrointestinal endoscopy which demonstrate reductions in hypoxemia but none specific to AFOI (6,7). Oxygenation during AFOI is of particular importance as patients undergoing the procedure typically have anatomically challenging airways which may be partially obstructed. The article pertains to adult patients only undergoing AFOI and not to those undergoing airway management under general anaesthesia. We present this article in accordance with the Narrative Review reporting checklist (available at https://joma.amegroups.com/article/view/10.21037/joma-2025-26/rc).

Methods

We conducted a literature search to identify studies reporting on oxygenation and complications, particularly hypoxemia during awake fibreoptic intubation (AFOI) (Table 1). The search was carried out across four major databases: PubMed, Scopus, Web of Science, and Google Scholar. Both Medical Subject Headings (MeSH) and free-text keywords were used. The core search strings was: (awake fiberoptic intubation OR awake fibre-optic intubation) AND (oxygenation OR oxygen) AND (complication OR hypoxia), with minor variations in quotation marks and spelling adapted to each database. No restrictions were placed on study type during the initial search.

The search was last updated on 1st June 2025, and studies published from 1950 up to this date were considered. Eligible studies were those that reported on adult patients (≥18 years) undergoing AFOI, examined oxygenation techniques or hypoxemia as an outcome, were published in English, and included observational studies, randomised controlled trials (RCTs), case series, or surveys. Exclusion criteria were studies restricted to paediatric populations, reports unrelated to AFOI, studies without intervention outcomes related to oxygenation or hypoxia respectively and animal studies.

All retrieved records were imported into a reference manager, and duplicate entries were removed. Two reviewers independently screened the titles and abstracts to assess eligibility. Full texts of potentially relevant articles were then reviewed. The initial search identified 2,128 records. After removing 567 duplicates, 1,561 unique records remained for screening. Of these, 1,442 reports were excluded for reasons including paediatric populations, irrelevance to the research question, lack of intervention, or absence of hypoxemia-related outcomes. Ultimately, 119 studies were read for the review. Additional studies were identified using reference lists and forward references using Google Scholar.

The incidence of hypoxemia during AFOI

The incidence of hypoxemia during AFOI varies considerably depending on the patient’s comorbidities, depth of sedation and oxygenation technique (8-10). It is among the most frequent complications of AFOI. In a recent survey of members of the Difficult Airway Society, 6.4% of respondents reported experiencing a oxygen saturation (SpO₂) of less than 80% during the procedure (2). In a recent meta-analysis of clinical studies of sedation techniques, El Bogdadly, identified a total of 48 studies which included 2,837 patients and 33 different regimens (11). In the RCTs which reported the incidence of arterial desaturation, a zero incidence was reported in 12 of these studies with all but one of the protocols involving some form of oxygen supplementation (12-23). In the studies in which oxygenation supplementation was not used prophylactically, the incidences of desaturation were 0% (17), 30% (24), 35% (25), 48% (26) and 80% (9). In the latter publication, the authors chose a threshold of hypoxemia of 95%, which is more conservative than the thresholds used in other studies and does not constitute a critical pathophysiological state. In studies where oxygen supplementation was used and hypoxemia still occurred, the incidence varied, ranging from 5% to 30%, indicating that supplemental oxygen does not guarantee adequate oxygenation (27-30). Notably, none of these studies utilised oxygen flows exceeding 4 L/min. The techniques included oxygen administration through the fibre-optic side port (19,28), bilateral nasal cannula (13,18,20,27,29-32), unilateral nasal cannula (15,33,34), nasopharyngeal airway (NPA) (14,22,35) and anaesthetic circuit pre-oxygenation (32,36). In an observational study of 327 neurosurgical patients with lesions of the cervical spine, 38/329 had SpO₂ of less than 90% (8). In this study, a variety of masks were used, and bolus sedation with midazolam and fentanyl was the sedation technique. Gueret, in a small study, reported that 6/46 patients desaturated to less than 90% in propofol-sedated patients receiving 10 L/min of pharyngeal oxygen (37). More recently, a 1.5% incidence was reported in a UK study of 600 patients, which was notable for the frequent (49%) use of HFNC (1).

Mechanisms of hypoxemia

Hypoxemia if sufficiently severe and prolonged, results in profound hypotension and rapid onset of cardiac systolic and diastolic dysfunction and neuronal injury (38). If severe hypoxemia occurs, the only effective treatment is restoration of oxygenation (39). AFOI carries significant risks of hypoxemia through multiple mechanisms. These include the effects of sedation, airway obstruction due to passage of the bronchoscope through areas of airway narrowing and less commonly airway reactivity. Sedatives can depress respiratory drive, and excessive sedation may result in reductions in respiratory rate and tidal volume and apnoeic episodes (40). Most sedatives also reduce the upper airway muscle tone, which can precipitate dynamic airflow obstruction (41). Direct mechanical obstruction also constitutes one of the causes of hypoxemia during this awake fiberoptic intubation, as the bronchoscope itself can significantly reduce the effective cross-sectional area of the airway. This is particularly problematic in patients with pre-existing airway narrowing, such as anatomical abnormalities, tumours, or inflammatory processes (42).

Routinely used topical application of local anaesthetic can also lead to dynamic airflow obstruction and complete upper airway collapse due to decreased tone of laryngeal muscles. This mechanism has been documented even in non-sedated patients, with lignocaine nebulisation or topical application, causing stridor and upper airway obstruction (43,44). Conversely, inadequate topical anaesthesia combined with airway instrumentation can trigger protective reflexes, such as laryngospasm (45). Laryngospasm can then cause complete airway obstruction and precipitate negative pressure pulmonary oedema as a secondary complication (46). The mechanism involves extreme negative pressure generated by respiratory muscles in an attempt to overcome airway obstruction. This causes increased venous return, elevated left ventricular afterload, and ultimately pulmonary capillary disruption.

Suctioning during AFOI can also contribute to hypoxemia and traditional suctioning techniques for secretion clearance have been associated with higher rates of desaturation (9). Suctioning through the bronchoscope can lead to lung decruitment and atelectasis formation.

Predictors of hypoxemia

Prediction of peri-procedural hypoxemia would help select patients who would benefit most from the most effective oxygenation techniques. The available evidence is heterogeneous, as many studies address bronchoscopy rather than intubation specifically, often involving diverse pharmacological agents and patient populations (47-49). Nonetheless, common contributory factors can be identified across these studies, offering insights applicable to clinical practice. Although many of the reviewed studies did not identify desaturation as a primary outcome, they consistently reported both patient-related and procedural factors associated with its occurrence.

Demographic factors such as age over 50 years, obesity, sleep apnea, and baseline hypoxemia have been consistently associated with an increased risk of desaturation (Table 2). Underlying pulmonary pathology requiring pre-operative oxygen supplementation, particularly pleural effusion and restrictive or obstructive lung disease, increases risk (47). Additional risk factors include increased age, male gender, smoking, and increasing severity of sleep apnoea (48-51). Excessive sedation is a modifiable risk factor for hypoxemia and is addressed later in this review.

Physiology of oxygen delivery

Low flow nasal cannula (LFNC) has been the most common means of oxygen supplementation to date. Oxygen leaving the tips of the cannula mixes with inhaled room air, and its oxygen content is diluted before reaching the alveolar space. The estimated fraction of inspired oxygen (FiO₂) increases with the flow rate and reaches a maximum of 44%, being strongly influenced by the patient’s peak inspiratory flow rate. At low flow rates, there is no increase in pressure in the oropharynx, and functional residual capacity is unaffected. The cannula can deliver substantially higher flows, comparable to HFNC. However, in awake subjects, this may cause discomfort, nasal dryness, and epistaxis. These side effects, however, have a low incidence in short-term use, and humidification is not a critical issue (52,53). Flows of 15 L/min were well tolerated in a 10-minute volunteer study (54). Simple face masks deliver higher FiO₂ (up to 60%) but limit access to the mouth and nose unless modified. The FiO₂ can be controlled using a Venturi mask, which delivers a maximum FiO₂ of 50% at a flow rate of 15 L/min (55). High flow nasal cannula can deliver an FiO₂ of up to 100% and generates positive airway pressure proportionate to the flow when the mouth is closed. It increases end-expiratory lung volumes and reduces the work of breathing (56). Its use in AFOI is increasing. Jet ventilation can be delivered through nasal tubes and has been used in diagnostic bronchoscopy and anaesthetised patients undergoing fibre-optic intubation (FOI) (57,58). Its mechanisms are complex and, in addition to bulk flow, are thought to involve laminar flow, Taylor-type dispersion, cardiogenic mixing, molecular diffusion and Pendelluft (56). During jet ventilation, air is entrained by the Venturi effect, oxygen is delivered to the lungs, and a positive airway pressure is generated.

Guidelines

The majority of contemporary airway guidelines do not advocate any particular method of oxygenation during AFOI (59-61). The British Thoracic Society guidelines for diagnostic or therapeutic bronchoscopy suggest supplementary oxygen for patients at high risk of hypoxemia only (62). The Difficult Airway Society guideline published in 2020 included multiple recommendations regarding patient safety during AFOI (11). The guideline recommends that supplemental oxygen always be used during AFOI. It advocates HFNO when available as the method of choice, but makes no recommendations on flow rate, humidification, or heating. This should be addressed in future guidelines.

Lessons from bronchoscopy trials

Six RCTs reported comparisons in 1,170 non-intubated patients for LFNC to HFNC during diagnostic or therapeutic bronchoscopy and were subject to meta-analysis (63). All six studies reported a reduction in desaturation events when HFNC was used, including two studies in which sedation was not used (64-69). In one study, the equipment was modified, and a single nasal cannula was used at a flow rate of 50 L/min (69). A further study compared HFNC using an FiO₂ of 50% at rates of 40 and 60 L/min with a Venturi mask. It found that HFNC was equivalent to the Venturi mask at 40 L/min and superior at 60 L/min (70). Based on the results of a dose-response study of HFNC flow at rates of between 10 and 60 L/min, Zhang recommended the use of 50–60 L/min to prevent hypoxemia (71). In contrast, Burton did not observe a difference in hypoxemia between HFNC at 40 L/min and FiO₂ 0.28 and LFNC in patients undergoing endobronchial ultrasound (EBUS) and clinicians were permitted to titrate oxygen (72).

Patient position

There are limited data on the effect of patient position on oxygenation. These data are from diagnostic and therapeutic bronchoscopy trials. In an RCT in which patients received intramuscular codeine 10 mg as a premedication but were otherwise non-sedated, patients were randomised to have the procedure in either the supine or sitting position (73). Oxygen was administered in 24% of participants by physician preference, and most underwent lung lavage. The proportion of patients whose SpO₂ dropped was greater in the sitting position, whether they were receiving supplementary oxygen or not (73). In patients receiving oxygen, the incidence of hypoxemia was 32% in the sitting position and 17% in the supine position. In an RCT of elderly patients with poor lung function, patients with mild post-sedation hypoxemia were randomised to the supine or semi-recumbent position (74). There were no differences between the groups, and it was notable that low flow oxygen supplementation at 2 L/min maintained oxygenation adequately in both positions. In an observational trial, Ling observed no difference between these positions; however, patients coughed less frequently in the sitting position (75). There are no comparable studies during AFOI, and no conclusive comments can be made on oxygen requirements in any particular position for AFOI other than recommending its universal use.

Sedation

Sedation is almost universal during AFOI. Sedation improves patient tolerance of the procedure and reduces discomfort. There are numerous methods and medication combinations used in sedation practice—these range from single injections to multidrug infusions. However, a balance is required between the benefits and the risks of sedation; with hypoventilation, oxygen desaturation, airway obstruction and cardiovascular compromise, all significant complications requiring management during the procedure. Correct sedation selection and management are therefore important considerations for a successful abrupt treatment interruption (ATI). The body of research concerning sedation during AFOI is difficult to compare directly, due to the wide variety of medications/techniques/qualitative vs. quantitative scoring of outcomes. To quantitatively synthesize the current studies, El-Boghdadly et al. recently published a systematic review and network meta-analysis of sedation used during AFOI, time to intubate, and the absence of adverse outcomes (10). They reported an intubation success rate of 99.3% using sedation. They analysed 32 trials with 1,813 patients. Sedation practices included dexmedetomidine, magnesium, remifentanil, fentanyl, sufentanil, propofol, ketamine, midazolam and nalbuphine. However, the lowest incidence of hypoxemia was observed when dexmedetomidine and magnesium were used (Table 3). The current DAS guideline recommends the use of remifentanil or dexmedetomidine as single-agent strategies for non-experts (11). A meta-analysis taht examined six studies comparing hypoxemia during AFOI when dexmedetomidine was directly compared to remifentanil found the incidence of hypoxemia to be lower in patients who received dexmedetomidine (7.6% vs. 20.3%) (76). Importantly, sedation should be used in combination with adequate topicalization and oxygenation. It is recommended that sedation be managed by someone other than the airway manager. Remimazolam is emerging as a promising option in this area. The optimal approach has not been determined, and the airway manager’s familiarity with the chosen sedation technique is more important than the selection of a particular agent.

LFNC

LFNCs are commonly used during AFOI. They are cheap and widely available. They have prongs that insert a short distance into both nostrils (Figure 1A). They are used in spontaneously breathing patients at flow rates not usually exceeding 6 L/min. As they entrain room air, they deliver no more than 44% O₂ and do not generate positive pressure in the airway. They have been modified for single nostril oxygen administration to allow AFOI through the contralateral nostril (15,33,34). Their use has been reported in studies investigating sedation techniques and AFOI equipment (13,18,20,27,29-32). The incidence of hypoxemia in these studies is summarised in the accompanying table and is generally low. The incidence in patients receiving dexmedetomidine is notably and consistently low, with a maximum incidence of 3%. In older studies using non-contemporary sedation techniques (midazolam/fentanyl), the incidence of hypoxemia with nasal cannula was 14.3% and 11.6% (8,77).

Figure 1 Devices used to administer oxygen during AFOI. (A) Low flow nasal cannula; (B) high flow nasal cannula; (C) nasopharyngeal airway; (D) Wei nasal jet tube; (E) intravenous cannula used for cricothyroid membrane or tracheal oxygenation. AFOI, awake fibre-optic laryngoscopy.

HFNC

High-flow nasal oxygen (HFNO) delivered through a specifically designed cannula has been utilised to provide non-invasive respiratory support to patients with respiratory failure (Figure 1B). Flow rates of 60 L/min or higher can be used, and the oxygen concentration can be adjusted. Heating and humidification of the inspired gas improve the system’s tolerability for patients. It is advocated as the technique of choice in the current Difficult Airway Society Awake Tracheal Intubation guideline (11). In addition to delivering high concentrations of oxygen, higher flows generate positive airway pressure, which in turn increases oxygenation. The technique may also improve laryngeal visualisation. The required equipment is specialised and requires electrical power, large quantities of oxygen, a heater, and a humidification source. In our literature search, we were unable to find any randomised trials comparing HFNO to other oxygenation techniques during AFOI. Neither were we able to find any dose control studies for flow or FiO₂. In a study of 600 patients in which it was used during AFOI, an incidence of 1.5% was reported (1). Badiger reported a zero incidence of hypoxemia in an observational study of 50 patients with anticipated difficult airways who were sedated with propofol and remifentanil infusions (78). In a retrospective study of 199 patients in which sedation was not standardised, no difference in desaturation was seen between LFNC and HFNC (79).

The optimal flow rate of HFNC is crucial for several reasons. Higher flow may improve oxygenation and visualisation of laryngeal structures, but also disperses exhaled gases, which may contain infected material and are a possible hazard to healthcare workers. Crowley et al. demonstrated that HFNO increases exhalation velocity by 2–3.9 times and cough velocity by 2.3–3 times compared with unassisted breathing and coughing, respectively (80). Using a computational fluid dynamics analysis, the model showed that droplets of 10–40 µm were most greatly affected. They estimated that a 1 m/s increase in velocity and a 1 s increase in duration caused an 80% increase in axial travel distance. Particles greater than 5 µm have been measured up to 3 meters away from the mouth and nose when HFNO is used (81).

Anaesthetic circuit pre-oxygenation

In a study of patients undergoing nasal intubation with a fibre-optic or Shikani optical stylette under midazolam/dexmedetomidine/remifentanil sedation (82). The subjects were pre-oxygenated to an expiratory tidal fraction of oxygen (ETO₂) of 90% and the mean intubation time was 74 seconds, and the incidence of desaturation to less than 90% was 16%. In an RCT of two sedation techniques, patients had pre-oxygenation with 100% O₂ via a Bain’s circuit (36). Patients in both groups had a baseline SpO₂ of 99% and no critical desaturation was seen in either group. Based on limited data, anaesthetic circuit pre-oxygenation would appear efficacious only for short-duration procedures, which cannot be guaranteed in difficult airway management.

NPAs

NPAs have the advantage of creating airway patency while also acting as conduits for oxygen delivery (Figure 1C). NPAs have been used to supply oxygen during AFOI at flows of less than 5 L/min during AFOI (14,22,35,37). In these studies, the devices were not specified, and details of insertion depth were not provided. The reported incidences of desaturation ranged from 0% to 13%. Recent developments in this area include an oropharyngeal oxygenation device (OOD) and the Wei nasal jet (WNJ) tube (57,83). These adjuncts work through oxygenation of the deep laryngeal space to improve oxygenation, with the latter device also allowing for jet ventilation. The OOD is a split oropharyngeal tube with channels for a bronchoscope and an external oxygen insufflation lumen. This allows delivery of oxygen while providing a dedicated route for the bronchoscope to pass, and likely provides a more direct route with splinting of the upper airway. Schroeder et al. used the OOD in a test lung of the manikin, and found that SpO₂ was maintained over 95% for 20 minutes with use of the OOD or through insufflation through the working channel of the bronchoscope, in contrast to use of a nasal cannula or the control group that received room air (83). The OOD allows the bronchoscope to use its working channel for suctioning. We were unable to find any studies of its clinical use in AFOI. The Wei tube consists of a polyvinyl chloride (PVC) tube with an internal diameter up to 7 mm. It can be used for low oxygen flows and for jet ventilation (Figure 1D). When used with low-flow oxygen or jet ventilation, it was compared with standard LFNC during flexible bronchoscopy under deep propofol-sufentanil-reminfentanil sedation; the lowest incidence of hypoxemia was seen in patients receiving jet ventilation (9.1%), and the highest in the standard nasal cannula group (86%) (57). Patients receiving 4 L oxygen had an incidence of hypoxemia of 61%.

There have, however, been several cases of gastric rupture when NPAs have been used during diagnostic bronchoscopy and peri-procedural oxygenation at flow rates of 4 L/min (84-86). Speculative mechanisms include distal placement of the catheter tip below the cricopharyngeus muscle, sedation-induced cricopharyngeal relaxation and stimulation of swallowing leading to gas entering the stomach during swallowing. This has led to suggestions that alternative techniques, which do not carry the same risks, be considered in preference to NPAs. The data on the OOD and WNJ are insufficient to make any comments in relation to their use during AFOI.

Supraglottic jet ventilation (SJV)

In the context of AFOI, SJV has been delivered through various NPAs. One of these is the WNJ tube (see above), which incorporates a 2 mm channel for jet ventilation and has been used in asleep FOIs and flexible bronchoscopies without significant hypoxemia (57,58). In Boyce’s observational study of 64 patients undergoing AFOI, a 14G cannula was placed within the nasal trumpet, and a Sanders Injector was used to deliver oxygen (Figure 1E) (87). There were no reported cases of hypoxemia, barotrauma or gastric distension. Jet ventilation has also been administered via the working channel of the fibre-optic scope in 16 patients undergoing diagnostic bronchoscopy who remained hypoxemic despite supplementary oxygen (88). In each case, oxygenation was restored to physiological levels within 30 seconds. These limited data establish the efficacy of these techniques, but the small number of patients is insufficient to determine their safety, and notably, there are no direct comparisons with HFNO.

Extracorporeal membrane oxygenation (ECMO)

ECMO has been used in a patient with multiple co-morbidities and a large goitre and associated tracheal stenosis. In this case, veno-venous ECMO was instituted after cannulation of the femoral vessels, and following initiation of sedation, an FOI was successfully performed (89). Lin reported the use of VV ECMO and topical anaesthesia for AFOI in a patient with a goitre, which had caused the airway to be compressed to 1.4 mm (90). Pre-emptive extracorporeal oxygenation is an evolving method of difficult airway management (91). This approach is only available in specialized centers and requires invasive vascular access and specialized equipment under the care of a multidisciplinary team. Readers are referred to a recent detailed review article specific to this topic (92).

Transtracheal narrow core catheter

There have been a small number of cases reported where narrow-bore catheters (13–18G) have been placed prophylactically through the cricothyroid membrane (CTM) for oxygen administration before attempted AFOI (Figure 1E) (93-96). Such techniques require specialised equipment such as transtracheal jet ventilation or a flow-regulated insufflation device, as well as expertise for safe use. Potential complications include the inability to locate the CTM, bleeding, catheter misplacement, kinking and barotrauma (97-99). There are no comparative trials of these devices with other oxygenation devices and data supporting this approach is limited.

Oxygenation via the working channel of FOB

There are numerous reports detailing the use of oxygen administration through the working channel of the FOB (9,19,32). Besides delivering oxygen, this method has the added benefit of keeping the field of view clear by displacing secretions and minimising lens fogging. In a benchtop model, Schroeder demonstrated that this technique maintained oxygen concentration in the test lung and was superior to the nasal cannula (83). Roh et al. evaluated its use in apnoeic patients at a flow rate of 5 L/min and found that it reduced the rate of deoxygenation (100). It has been used in several RCTs that assessed different sedation techniques at a flow rate of 2 L/min (9,19,28,32). In two of these trials, the incidence of desaturation was notably high, with up to 80% of subjects becoming hypoxic. Heidegger et al. described its application at a flow rate of 4 L/min in 1,612 oral and nasal intubations without associated complications, though they did not report the incidence of hypoxemia (101). A recent review of the literature identified several serious complications related to the technique, including subcutaneous emphysema, pneumothorax, gastric rupture, and death (102-104). The authors concluded that for the technique to be considered safe, it would be necessary to limit the delivered pressure to 40 cmH₂O, something that current delivery systems do not guarantee (104). There are no studies that evaluate the effectiveness of different flow rates on either the efficacy of oxygenation or safety and no direct comparisons with other approaches. As both HFNO and low flow cannula have long-established safety profiles, they seem preferable in the absence of the ability to limit pressure through the working channel of the FOB as described above.

Strengths and limitations

There are a number of limitations to this review. First, the majority of the evidence presented is based on observational work in heterogeneous patient populations undergoing AFOI with non-standardised sedation and airway topicalization techniques. Second, some of the evidence is derived from bronchoscopy literature, which may not be directly comparable to AFOI. More definitive conclusions can only be made with direct comparison of methods in prospective randomised studies. As with other narrative reviews, it does not have the methodological rigour of a systematic review. The authors have, however, attempted to reduce any bias by completing a broad literature search based on a previously used methodology (105).

Conclusions

It is currently recommended that all patients undergoing AFOI receive supplementary oxygen during the procedure. Although HFNO is the recommended method of oxygen administration, there are limited data to support this, and simpler, cheaper technologies are adequate for many patients. Other approaches described include LFNC, anaesthetic circuit oxygenation, NPAs, supraglottic jet ventilation, ECMO, transtracheal narrow-bore catheters, and delivery of oxygen via the working channel of the fibre-optic bronchoscope. We were unable to establish a clear superiority of any particular technique in maintaining oxygenation. Owing to the low numbers of patients described in studies reporting some of these techniques, their safety cannot be determined. The authors recommend risk-stratifying patients to determine the method of oxygenation and using HFNO in those at higher risk of hypoxemia. Equally important is the adequacy of topicalization and the use of a safe sedation technique and limitation of the depth of sedation to no more than required.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the Narrative Review reporting checklist. Available at https://joma.amegroups.com/article/view/10.21037/joma-2025-26/rc

Peer Review File: Available at https://joma.amegroups.com/article/view/10.21037/joma-2025-26/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://joma.amegroups.com/article/view/10.21037/joma-2025-26/coif). C.M. serves as an unpaid editorial board member of Journal of Oral and Maxillofacial Anesthesia from January 2025 to December 2026. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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