title: Heat and moisture exchange capacity of the upper respiratory tract and the effect of tracheotomy breathing on endotracheal climate.
abstract: BACKGROUND
  The aim of this study was to assess the heat and moisture exchange (HME) capacity of the upper respiratory tract and the effect of tracheotomy breathing on endotracheal climate in patients with head and neck cancer.
  
  
  METHODS
  We plotted the subglottic temperature and humidity measurements in 10 patients with head and neck cancer with a temporary precautionary tracheotomy during successive 10-minute periods of nose, mouth, and tracheotomy breathing in a randomized sequence.
  
  
  RESULTS
  End-inspiratory temperatures of nose, mouth, and tracheotomy breathing were 31.1, 31.3, and 28.3°C, respectively. End-inspiratory humidity measurements of nose, mouth, and tracheotomy breathing were 29.3, 28.6, and 21.1 mgH₂O/L, respectively. There was a trend toward lower end-inspiratory humidity in patients with radiotherapy or with large surgery-induced oropharyngeal mucosal defects, whereas temperatures were similar.
  
  
  CONCLUSIONS
  This study gives objective information about the HME capacity of the upper respiratory tract in patients with head and neck cancer with precautionary tracheotomy, and thus provides target values for HMEs for laryngectomized and tracheotomized patients.
authors.affiliation: Department of Head and Neck Oncology and Surgery, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
authors.forename: Renske J
authors.initials: RJ
authors.lastname: Scheenstra
authors.forename: Sara H
authors.initials: SH
authors.lastname: Muller
authors.forename: Andrew
authors.initials: A
authors.lastname: Vincent
authors.forename: Frans J M
authors.initials: FJ
authors.lastname: Hilgers
mesh_terms: D000328:Adult; D000368:Aged; D001784:Blood Gas Analysis; D001833:Body Temperature Regulation; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000473:pathology / Q000601:surgery*; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D007442:Intubation, Intratracheal; D016014:Linear Models; D008297:Male; D008451:Maximal Voluntary Ventilation; D008875:Middle Aged; D009055:Mouth / Q000503:physiopathology; D009058:Mouth Breathing / Q000503:physiopathology; D037981:Neck Dissection / Q000379:methods; D009666:Nose / Q000503:physiopathology; D010101:Oxygen Consumption / Q000502:physiology*; D011182:Postoperative Care / Q000379:methods*; D012131:Respiratory Insufficiency / Q000517:prevention & control; D018570:Risk Assessment; D014132:Trachea / Q000503:physiopathology*; D014140:Tracheotomy / Q000379:methods*; D055815:Young Adult