Objectives/background: Sleep laboratory polysomnography (PSG) is the gold standard for obstructive sleep apnea (OSA) diagnosis in infants, but its access remains limited. Another simple and widely used tool, oximetry-capnography can provide information on the presence of desaturations and alveolar hypoventilation. However, its reliability is debated. This study aimed at examining its use in determining OSA severity in infants. Patients/methods: This retrospective study was conducted in a sleep unit in a tertiary hospital, in infants < 4 months old with clinical signs of OSA or Pierre Robin Sequence (PRS) who underwent a one-night PSG coupled with oximetry-capnography. Results: Among the 78 infants included (median [IQR] age: 61 [45-89] days at PSG), 44 presented with PRS, and 34 presented with isolated airway obstruction. The clinical, sleep and respiratory characteristics were not significantly different between the two subgroups. In the entire cohort, 63.5% had severe OSA. Median OAHI was 14.5/h [7.4-5.9], Spo2 was 97.4% [96.5-98.1], and PtCO2 was 41.1 mmHg [38.3-44.9]. The optimal threshold to predict OAHI > 10/h was 6/h for OD3% (sensitivity 95.7%, specificity 51.9%) and 2/h for OD4% (sensitivity 95.7%, specificity 48.1%). Conclusion: Whereas transcutaneous capnography does not appear to be sufficient in predicting severe OSA in infants < 4 months old with PRS or clinical signs of OSA, oximetry may be a useful alternative for the screening of severe OSA in infants in the absence of PSG.

Introduction: Periodic breathing (PB) is considered physiological in the neonatal period but must disappear in the first months of life. Few data regarding PB after the neonatal period are available. The objective of this study was to describe the clinical and polysomnographic characteristics of infants presenting with PB after the age of 1 month. Methods: This French multicenter retrospective case series included infants born at term between 2012 and 2021, without underlying disease, and who presented during a polysomnography (PSG) recording more than 1% of PB after 1 month of life. Results: Overall, 10 infants were included, they underwent a PSG for brief resolved unexplained event, desaturation, pauses in breathing, cyanosis, and/or signs of respiratory distress. The percentage of total sleep time spent with PB was 18.1% before 3 months (n=7), 4.7% between 3 and 6 months (n=10), 7.1% between 7 and 12 months (n=2), and 0% after 12 months (n=2). During the first PSG, ≥ 3% desaturations were observed in 77% to 100% of the PB episodes. At the first PSG, 9/10 infants had an obstructive apnea hypopnea index > 10/h and 5/10 had a central apnea index > 5/h. Gastro-esophageal reflux (GER) was suspected in 8/10 infants. All infants showed improvement in initial symptoms during the first year of life. Conclusion: Although PB is rare after 1 month of age, the present study shows that when present, PB is most frequently associated with obstructive and/or central apnea syndrome in term infants without comorbidities other than GER.