title: Heated humidification improves clinical outcomes, compared to a heat and moisture exchanger in children with tracheostomies.
abstract: BACKGROUND
  The upper airway humidifies and warms inspired gases before they reach the trachea, a process bypassed by the insertion of a tracheostomy, necessitating humidification of inspired gases. The optimal method of humidification is not known.
  
  
  METHODS
  We conducted a short-term 20-hour study and a long-term 10-week randomized crossover study comparing a heated humidifier (HH) to a heat and moisture exchanger (HME) in children with established tracheostomies. Subjects were assessed for clinical events, clinical examination findings, airway cytokine levels, and airway secretion viscoelasticity.
  
  
  RESULTS
  For the short-term study, 15 children were recruited; for the long-term study, 14 children were recruited. Children using the HH had decreased respiratory examination score (P < .001) but no change in clinical events over the short term. There was a decrease in acute clinical events (P = .008) in the long-term study. No differences were found in airway secretion viscoelasticity results or cytokine levels in either study, but these sample numbers were limited.
  
  
  CONCLUSIONS
  Over 20 hours use, HH, compared to HME, improved work of breathing. Over a longer 10 week treatment period HH resulted in decreased adverse clinical events.
authors.affiliation: Department of Paediatrics, Child and Youth Health, University of Auckland, and with Starship Children's Hospital, Grafton, Auckland, New Zealand.
authors.forename: David G
authors.initials: DG
authors.lastname: McNamara
authors.forename: M Innes
authors.initials: MI
authors.lastname: Asher
authors.forename: Bruce K
authors.initials: BK
authors.lastname: Rubin
authors.forename: Alistair
authors.initials: A
authors.lastname: Stewart
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Byrnes
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D018592:Cross-Over Studies; D016207:Cytokines / Q000378:metabolism; D055119:Elastic Modulus; D005260:Female; D005740:Gases; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D007223:Infant; D007231:Infant, Newborn; D001239:Inhalation; D008297:Male; D009079:Mucociliary Clearance; D020545:Respiratory Mucosa / Q000378:metabolism; D056152:Respiratory Rate; D013997:Time Factors; D014139:Tracheostomy / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D014783:Viscosity; D014939:Work of Breathing
chemical_list: D016207:Cytokines; D005740:Gases
keywords: child; humidity; inflammation; mucociliary clearance; randomized controlled trial; rheology; tracheostomy