title: Aerosol Therapy in Adults Receiving High Flow Nasal Cannula Oxygen Therapy.
abstract: BACKGROUND
  High flow nasal cannula oxygen therapy (HFT) is increasingly used in intensive and emergency care departments. Patients suffering from respiratory failure, who are likely to benefit from HFT, may require aerosolized bronchodilators; therefore, combining nebulization with HFT may be relevant. This study aimed to identify the optimal settings for the implementation of nebulization within an adult HFT circuit.
  
  
  METHODS
  We assessed the mass and the particle size distribution of the aerosol emitted from the nasal cannula (inhalable mass) using mesh- and jet-nebulizers placed at various positions in the HFT circuit. Thereafter, the most relevant combination was used to evaluate the mass of salbutamol delivered downstream of an anatomical model reproducing aerosol deposition and leakage at the nasal and pharyngeal levels (respirable mass). The influence of HFT flow rate (30, 45, and 60 L/min), of breathing pattern (quiet and respiratory distress pattern) as well as of opened and closed mouth breathing was assessed.
  
  
  RESULTS
  The most efficient position was that of a nebulizer placed upstream from the humidification chamber (inhalable mass ranging from 26% to 32% of the nebulizer charge). Using a mesh nebulizer, we observed a respirable mass ranging from 2% to 10% of the nebulizer charge. Higher HFT flow rates and open mouth breathing were associated with a lower efficiency. Simulating respiratory distress (i.e., increasing the simulated patient inspiratory flow) did not hamper drug delivery as compared to a quiet breathing pattern.
  
  
  CONCLUSIONS
  Placing nebulizers within a HFT circuit upstream from the humidification chamber may enable to deliver clinically relevant masses of aerosol at the cannula outlet, but more importantly downstream of the nose and pharynx, even in case of high patients' inspiratory flow. This method of aerosol therapy is expected to produce a bronchodilatatory effect to be evaluated in the clinical settings.
authors.affiliation: 1 Université François Rabelais , Tours, France .|2 INSERM , Centre d'Étude des Pathologies Respiratoires, Tours, France .|3 Pôle d'anesthésie-réanimation, CHRU de Tours , Tours, France .|4 Réanimation polyvalente, CHRU de Tours , Tours, France .
authors.forename: François
authors.initials: F
authors.lastname: Réminiac
authors.affiliation: 1 Université François Rabelais , Tours, France .|2 INSERM , Centre d'Étude des Pathologies Respiratoires, Tours, France .|5 Aerodrug, DTF Medical , Faculté de médecine, Tours, France .
authors.forename: Laurent
authors.initials: L
authors.lastname: Vecellio
authors.affiliation: 1 Université François Rabelais , Tours, France .|2 INSERM , Centre d'Étude des Pathologies Respiratoires, Tours, France .
authors.forename: Nathalie
authors.initials: N
authors.lastname: Heuzé-Vourc'h
authors.affiliation: 6 Pharmacologie-toxicologie, CHRU de Tours , Tours, France .
authors.forename: Antoine
authors.initials: A
authors.lastname: Petitcollin
authors.affiliation: 7 Pharmacie, CHRU de Tours , Tours, France .
authors.forename: Renaud
authors.initials: R
authors.lastname: Respaud
authors.affiliation: 1 Université François Rabelais , Tours, France .|2 INSERM , Centre d'Étude des Pathologies Respiratoires, Tours, France .
authors.forename: Maria
authors.initials: M
authors.lastname: Cabrera
authors.affiliation: 1 Université François Rabelais , Tours, France .|2 INSERM , Centre d'Étude des Pathologies Respiratoires, Tours, France .
authors.forename: Deborah Le
authors.initials: DL
authors.lastname: Pennec
authors.affiliation: 1 Université François Rabelais , Tours, France .|2 INSERM , Centre d'Étude des Pathologies Respiratoires, Tours, France .|8 Pneumologie, CHRU de Tours , Tours, France .
authors.forename: Patrice
authors.initials: P
authors.lastname: Diot
authors.affiliation: 1 Université François Rabelais , Tours, France .|2 INSERM , Centre d'Étude des Pathologies Respiratoires, Tours, France .|4 Réanimation polyvalente, CHRU de Tours , Tours, France .
authors.forename: Stephan
authors.initials: S
authors.lastname: Ehrmann
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols; D000420:Albuterol / Q000008:administration & dosage*; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D000072601:Cannula; D004867:Equipment Design; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008953:Models, Anatomic; D009330:Nebulizers and Vaporizers; D010102:Oxygen Inhalation Therapy / Q000295:instrumentation*; D010316:Particle Size; D012131:Respiratory Insufficiency / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D015656:Respiratory Mechanics
chemical_list: D000336:Aerosols; D001993:Bronchodilator Agents; D000420:Albuterol
keywords: albuterol; inhalation; nebulizers and vaporizers; oxygen inhalation therapy