title: Infants with viral bronchiolitis demonstrate two distinct patterns of nocturnal oxyhaemoglobin desaturation.
abstract: OBJECTIVE
  This study aimed to demonstrate that viral bronchiolitis is associated with intermittent oxygen saturation of haemoglobin (SpO2 ) drops (≥3%) and low basal SpO2 between episodes of haemoglobin desaturation.
  
  
  METHODS
  Infants with bronchiolitis underwent pulse oximetry during the first night following hospital admission and a subgroup of them underwent repeat oximetry before hospital discharge. Oximetry was also performed in infants with partial upper airway obstruction (UAO) and without lung disease and in control participants without UAO or lung disease.
  
  
  RESULTS
  We enrolled 53 infants: 21 with bronchiolitis, 11 with UAO and 21 healthy controls. Participants with bronchiolitis had lower basal SpO2 (median 93.7% [10th-90th percentiles: 91.1-96.8]) than the subjects with UAO (96.9% [95.3-98.1]; p < 0.01) or the controls (98.7% [96.9-99.3]; p < 0.01). The bronchiolitis group was not different from the UAO group regarding the desaturation index (23.3 episodes/hour [10.3-46.6] and 15.5 episodes/hour [5.4-36.4], respectively; p = 0.08), but differed significantly from the controls (3.1 episodes/hour [0.3-5.5]; p < 0.01). The basal SpO2 and desaturation index improved in 10 subjects with bronchiolitis who had follow-up oximetry before discharge, but these indices remained abnormal when compared to values in the control group.
  
  
  CONCLUSIONS
  Bronchiolitis was characterised by low nocturnal basal SpO2 and intermittent SpO2 drops.
authors.affiliation: Paediatric Pulmonology and Allergy Units, Sleep Disorders Laboratory, First Department of Paediatrics, National and Kapodistrian University of Athens School of Medicine and Aghia Sophia Children's Hospital, Athens, Greece.
authors.forename: Athanasios G
authors.initials: AG
authors.lastname: Kaditis
authors.forename: Georgia
authors.initials: G
authors.lastname: Katsouli
authors.forename: Georgia
authors.initials: G
authors.lastname: Malakasioti
authors.forename: Katerina
authors.initials: K
authors.lastname: Kaffe
authors.forename: Vasiliki
authors.initials: V
authors.lastname: Gemou-Engesaeth
authors.forename: Emmanouel I
authors.initials: EI
authors.lastname: Alexopoulos
mesh_terms: D015415:Biomarkers / Q000097:blood; D001990:Bronchiolitis, Viral / Q000097:blood / Q000503:physiopathology*; D016022:Case-Control Studies; D002940:Circadian Rhythm; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D010092:Oximetry; D010100:Oxygen / Q000097:blood*; D010108:Oxyhemoglobins / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D010108:Oxyhemoglobins; D010100:Oxygen
keywords: bronchiolitis; infancy; nocturnal hypoxaemia; oximetry; sleep-disordered breathing