ObjectiveHeated humidified high flow nasal cannula (HHHFNC) has gained popularity in the treatment of children with respiratory distress and bronchiolitis in the past decade. Its efficacy as a mode of non-invasive respiratory support has been demonstrated in both adults and children. However, reports on its use in the treatment of obstructive sleep apnea (OSA) in infants are limited. We aimed to evaluate the efficacy of HHHFNC therapy as treatment in infants with OSA. MethodsA retrospective analysis of OSA infants who had undergone polysomnographic titration between 2015 and 2017 was undertaken. Data about the age, gender, AHI, co-morbid conditions and flow used for each patient were retrieved. ResultsTen infants were included in this study (median age 34 weeks; IQR 27–38 weeks). The median optimal HHHFNC flow rate was 8.0 L/min (IQR 6.7–8.0 L/min). HHHFNC significantly reduced median obstructive apnea–hypopnea index (OAHI) from 9.1 (IQR 5.1–19.3) to 0.9 (IQR 0–1.6; P = 0.005) events/h; median obstructive apnea index (OAI) from 5.8 (IQR 1.1–13.4) to 0 (IQR 0–0.9; P = 0.021) events/h; median obstructive hypopnea index (OHI) from 4.1 (IQR 0.9–6.8) to 0.1 (0–0.9; P = 0.017) events/h; and median oxygen saturation (SpO2) nadir increased from 88% (IQR 83–94%) to 94% (IQR 93–96%; P = 0.040). ConclusionHHHFNC significantly reduced respiratory events and improved oxygenation in infants with OSA.