title: Mechanical ventilation drives inflammation in severe viral bronchiolitis.
abstract: BACKGROUND
  Respiratory insufficiency due to severe respiratory syncytial virus (RSV) infection is the most frequent cause of paediatric intensive care unit admission in infants during the winter season. Previous studies have shown increased levels of inflammatory mediators in airways of mechanically ventilated children compared to spontaneous breathing children with viral bronchiolitis. In this prospective observational multi-center study we aimed to investigate whether this increase was related to disease severity or caused by mechanical ventilation.
  
  
  METHODS
  Nasopharyngeal aspirates were collected <1 hour before intubation and 24 hours later in RSV bronchiolitis patients with respiratory failure (n = 18) and non-ventilated RSV bronchiolitis controls (n = 18). Concentrations of the following cytokines were measured: interleukin (IL)-1α, IL-1β, IL-6, monocyte chemotactic protein (MCP)-1 and macrophage inflammatory protein (MIP)-1α.
  
  
  RESULTS
  Baseline cytokine levels were comparable between ventilated and non-ventilated infants. After 24 hours of mechanical ventilation mean cytokine levels, except for MIP-1α, were elevated compared to non-ventilated infected controls: IL-1α (159 versus 4 pg/ml, p<0.01), IL-1β (1068 versus 99 pg/ml, p<0.01), IL-6 (2343 versus 958 pg/ml, p<0.05) and MCP-1 (174 versus 26 pg/ml, p<0.05).
  
  
  CONCLUSIONS
  Using pre- and post-intubation observations, this study suggests that endotracheal intubation and subsequent mechanical ventilation cause a robust pulmonary inflammation in infants with RSV bronchiolitis.
authors.affiliation: Department of Paediatric Intensive Care, Wilhelmina Children's Hospital / University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Marije P
authors.initials: MP
authors.lastname: Hennus
authors.affiliation: Department of Paediatric Intensive Care, Wilhelmina Children's Hospital / University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Adrianus J
authors.initials: AJ
authors.lastname: van Vught
authors.affiliation: Department of Paediatric Intensive Care, Wilhelmina Children's Hospital / University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Mark
authors.initials: M
authors.lastname: Brabander
authors.affiliation: Department of Paediatrics, Haga Hospital/Location Juliana Children's Hospital, The Hague, The Netherlands.
authors.forename: Frank
authors.initials: F
authors.lastname: Brus
authors.affiliation: Department of Paediatric Intensive Care, Wilhelmina Children's Hospital / University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Nicolaas J
authors.initials: NJ
authors.lastname: Jansen
authors.affiliation: Department of Paediatric Infectious Diseases, Wilhelmina Children's Hospital/University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Bont
mesh_terms: D001990:Bronchiolitis, Viral / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D016207:Cytokines / Q000378:metabolism*; D005260:Female; D006801:Humans; D007223:Infant; D007249:Inflammation / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D008297:Male; D012121:Respiration, Artificial / Q000009:adverse effects*; D018357:Respiratory Syncytial Virus Infections / Q000378:metabolism* / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D012136:Respiratory Syncytial Viruses; D012621:Seasons
chemical_list: D016207:Cytokines