High-flow nasal cannula (HFNC) provides conditioned high-flow oxygen through an open system with high pressure and high velocity. HFNC has been widely used in neonatal patients with comparable benefit to CPAP; however, the use in pediatric patients has not been well evaluated. In pediatric patients, a regular nasal cannula is widely used as oxygen therapy, but the flow provided is limited because the humidity is not optimal. While HFNC as noninvasive oxygen therapy can deliver heated, humidified gas, via nasal cannula. High-velocity HFNC makes oxygen-rich gases occupy the dead space of the nasopharynx, increasing FiO₂, and improving alveolar ventilation. The use of HFNC in children begins with bronchiolitis patients, also considered effective in various respiratory disorders including cases of hypoxemic respiratory failure. HFNC has been shown to have a better patient tolerance, less nose damage, and less work for the staff than CPAP and noninvasive ventilators (NIV). HFNC can be used in the emergency department and even the patient ward, while CPAP and NIV require intensive care unit facility as it needs close monitoring. HFNC is considered safe with mild side effects such as epistaxis and skin irritation that have been reported. While serious side effects such as pneumothorax are rarely reported because open system HFNC can prevent a sudden increase in airway pressure.

The pathophysiology of obstructive sleep apnoea (OSA) is well studied in the adult population, but not in the paediatric population, although it can be generally classified into anatomical, functional, and pathological factors, with the most common aetiology being adenotonsillar hypertrophy and a reduced neuromuscular tone of the upper airway (UA) muscles. It is vital to understand the pathophysiology behind paediatric OSA, so that treatment can be optimized. Although the first-line treatment remains to be adenotonsillectomy (AT), this is not always effective, as indicated by the complex pathophysiology of OSA, leading to residual OSA post-AT. Myofunctional therapy (MFT), a newer non-invasive method focusing on re-educating, strengthening, and stimulating UA muscles, improves neuromuscular tone and prevents airway collapse, as supported by multiple randomized controlled trials (RCTs). Outcomes after 2 months to 2 years of therapy have also been positive, with children experiencing improved sleep quality, reduced emotional distress and mood swings, and reduced daytime problems, whereas polysomnogram (PSG) results revealed a clinically significant reduced apnoea–hypopnoea index post-therapy. Major limitations include poor compliance for active MFT and the short duration of the studies with small sample sizes. Given the high prevalence rates of childhood OSA, it is essential that more high-quality studies and RCTs are performed to assess the effectiveness of this treatment method, with a specific emphasis on its long-term impacts, risks, and optimal treatment duration.

Background: Drug-induced sleep endoscopy (DISE) is an objective assessment and diagnostic procedure of the upper airway obstruction (UAO) under sedation. Findings of DISE in Hong Kong pediatric group patients with obstructive sleep apnea (OSA) are limited. Materials and Methods: This is a single-center retrospective chart review study on DISE findings in pediatric patients with OSA documented by polysomnography (PSG). We used the DISE scoring system proposed by Chan 2014, Fishman 2013 together as our internal practice. A standard sedation protocol was conducted. Endoscopic findings were recorded and evaluated the level of obstruction, severity, and correlation with PSG parameters. Results: A total of 124 patients who underwent DISE were reviewed in our study. Multiple levels of obstruction had been observed in all patients. Forty-five (36.6%) patients suffered from severe obstruction in more than one level. Tongue base was the most common level being severely obstructed. DISE total score is positively correlated with obstructive apnea-hypopnea index (oAHI, r = 0.35, P = <0.001), negatively correlated with oxygen nadir (SpO2 nadir, r = –0.32, P = <0.001), and positively correlated with desaturation index (DI, r = 0.34, P < 0.001). In the subgroup analysis of the post-adenotonsillectomy (AT) group, scores in nostrils, tongue base, and supraglottic showed significantly increased. None of the subjects had complications from sedation or the endoscopy procedure. Conclusion: In our study, DISE was shown to be a safe, feasible, and informative assessment tool for pediatric OSA patients. In particular, multiple levels of obstruction were common in children and we observed a significant correlation between the severity of UAO measured by DISE in children with OSA and PSG parameters. Changes in UAO sites were observed when preoperative patients underwent surgical treatment.