title: Small dead space heat and moisture exchangers do not impede gas exchange during noninvasive ventilation: a comparison with a heated humidifier.
abstract: OBJECTIVE
  Adverse respiratory and gasometrical effects have been described in patients with acute respiratory failure (ARF) undergoing noninvasive ventilation (NIV) with standard heat and moisture exchangers (HME). We decided to evaluate respiratory parameters and arterial blood gases (ABG) of patients during NIV with small dead space HME compared with heated humidifier (HH).
  
  
  METHODS
  Prospective randomized crossover study.
  
  
  METHODS
  A 16-bed medical intensive care unit (ICU).
  
  
  METHODS
  Fifty patients receiving NIV for ARF.
  
  
  METHODS
  The effects of HME and HH on respiratory rate, minute ventilation, EtCO(2), oxygen saturation, airway occlusion pressure at 0.1 s, ABG, and comfort perception were compared during two randomly determined NIV periods of 30 min. The relative impact of HME and HH on these parameters was successively compared with or without addition of a flex tube (40 and 10 patients, respectively).
  
  
  RESULTS
  No difference was observed between HME and HH regarding any of the studied parameters, whether or not a flex tube was added.
  
  
  CONCLUSIONS
  If one decides to humidify patients' airways during NIV, one may do so with small dead space HME or HH without altering respiratory parameters.
authors.affiliation: Département de Réanimation Médicale, Hôpital Pellegrin-Tripode, Place A. Raba Léon, 33076 Bordeaux Cedex, France. alexandre.boyer@chu-bordeaux.fr
authors.forename: Alexandre
authors.initials: A
authors.lastname: Boyer
authors.forename: Frederic
authors.initials: F
authors.lastname: Vargas
authors.forename: Gilles
authors.initials: G
authors.lastname: Hilbert
authors.forename: Didier
authors.initials: D
authors.lastname: Gruson
authors.forename: Maud
authors.initials: M
authors.lastname: Mousset-Hovaere
authors.forename: Yves
authors.initials: Y
authors.lastname: Castaing
authors.forename: Didier
authors.initials: D
authors.lastname: Dreyfuss
authors.forename: Jean Damien
authors.initials: JD
authors.lastname: Ricard
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018592:Cross-Over Studies; D005260:Female; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D009330:Nebulizers and Vaporizers; D011175:Positive-Pressure Respiration; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012119:Respiration; D012126:Respiratory Dead Space; D012131:Respiratory Insufficiency