title: Noninvasive positive pressure ventilation delivered by helmet vs. standard face mask.
abstract: OBJECTIVE
  This bench and human study compared large and small helmets with face mask (FM) for delivery of noninvasive positive pressure ventilation.
  
  
  METHODS
  A lung simulator was employed, and the human study involved six healthy subjects. We evaluated a continuous high-flow (CPAPHF), low flow (CPAPLF), ventilator (CPAPVENT) CPAP, and pressure support ventilation (PSV 10 and 20 cmH2O). In the human study we used CPAPHF, CPAPVENT, and PSV 5 cmH2O. PEEP was 5 cmH2O.
  
  
  METHODS
  In the bench study during CPAP we measured the negative airway pressure time product (areaCPAP), i.e., the area of airway pressure (Paw) under PEEP and during PSV the pressure airway time product (areaPSV), i.e., the area of Paw from onset to end of inspiratory flow. In the human study we measured the breathing pattern and work of breathing (WOB).
  
  
  RESULTS
  In the bench study during CPAPLF the helmets had a lower areaCPAP than the FM, while during CPAPHF the three interfaces had similar areaCPAP. Using CPAPVENT and PSV the FM reduced areaCPAP and increased areaPSV compared to helmets. At 20 cmH2O of PSV using helmets areaPSV was similar to that obtained at 10 cmH2O of PSV using the FM. In human study using CPAPHF and CPAPVENT the tree interfaces had similar effects on breathing pattern and WOB, while using PSV the FM reduced WOB more than helmets.
  
  
  CONCLUSIONS
  During CPAPLF helmets were more efficient than FM, while during CPAPHF the three interfaces were comparable. Using CPAPVENT and PSV, FM was more efficient than helmets
authors.affiliation: Istituto di Anestesia e Rianimazione, Ospedale Maggiore Policlinico-IRCCS, Universita' degli Studi di Milano, via Francesco Sforza 35, 20122 Milan, Italy. chiumello@libero.it
authors.forename: Davide
authors.initials: D
authors.lastname: Chiumello
authors.forename: Paolo
authors.initials: P
authors.lastname: Pelosi
authors.forename: Eleonora
authors.initials: E
authors.lastname: Carlesso
authors.forename: Paolo
authors.initials: P
authors.lastname: Severgnini
authors.forename: Michele
authors.initials: M
authors.lastname: Aspesi
authors.forename: Chiara
authors.initials: C
authors.lastname: Gamberoni
authors.forename: Massimo
authors.initials: M
authors.lastname: Antonelli
authors.forename: Giorgio
authors.initials: G
authors.lastname: Conti
authors.forename: Maurizio
authors.initials: M
authors.lastname: Chiaranda
authors.forename: Luciano
authors.initials: L
authors.lastname: Gattinoni
mesh_terms: D004867:Equipment Design; D006801:Humans; D008397:Masks; D008953:Models, Anatomic; D011175:Positive-Pressure Respiration / Q000295:instrumentation*; D012131:Respiratory Insufficiency / Q000628:therapy*