title: In vitro surfactant and perfluorocarbon aerosol deposition in a neonatal physical model of the upper conducting airways.
abstract: OBJECTIVE
  Aerosol delivery holds potential to release surfactant or perfluorocarbon (PFC) to the lungs of neonates with respiratory distress syndrome with minimal airway manipulation. Nevertheless, lung deposition in neonates tends to be very low due to extremely low lung volumes, narrow airways and high respiratory rates. In the present study, the feasibility of enhancing lung deposition by intracorporeal delivery of aerosols was investigated using a physical model of neonatal conducting airways.
  
  
  METHODS
  The main characteristics of the surfactant and PFC aerosols produced by a nebulization system, including the distal air pressure and air flow rate, liquid flow rate and mass median aerodynamic diameter (MMAD), were measured at different driving pressures (4-7 bar). Then, a three-dimensional model of the upper conducting airways of a neonate was manufactured by rapid prototyping and a deposition study was conducted.
  
  
  RESULTS
  The nebulization system produced relatively large amounts of aerosol ranging between 0.3±0.0 ml/min for surfactant at a driving pressure of 4 bar, and 2.0±0.1 ml/min for distilled water (H2Od) at 6 bar, with MMADs between 2.61±0.1 µm for PFD at 7 bar and 10.18±0.4 µm for FC-75 at 6 bar. The deposition study showed that for surfactant and H2Od aerosols, the highest percentage of the aerosolized mass (∼65%) was collected beyond the third generation of branching in the airway model. The use of this delivery system in combination with continuous positive airway pressure set at 5 cmH2O only increased total airway pressure by 1.59 cmH2O at the highest driving pressure (7 bar).
  
  
  CONCLUSIONS
  This aerosol generating system has the potential to deliver relatively large amounts of surfactant and PFC beyond the third generation of branching in a neonatal airway model with minimal alteration of pre-set respiratory support.
authors.affiliation: Research Unit for Experimental Neonatal Respiratory Physiology, Cruces University Hospital, Barakaldo, Bizkaia, Spain; Thermal and Fluids Engineering Division, Mechanical Engineering Department, TECNUN, University of Navarra, San Sebastian, Gipuzkoa, Spain.
authors.forename: Estibalitz
authors.initials: E
authors.lastname: Goikoetxea
authors.affiliation: Research Unit for Experimental Neonatal Respiratory Physiology, Cruces University Hospital, Barakaldo, Bizkaia, Spain.
authors.forename: Xabier
authors.initials: X
authors.lastname: Murgia
authors.affiliation: Research Unit for Experimental Neonatal Respiratory Physiology, Cruces University Hospital, Barakaldo, Bizkaia, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Serna-Grande
authors.affiliation: Neonatal Intensive Care Unit, Cruces University Hospital, Barakaldo, Bizkaia, Spain.
authors.forename: Adolf
authors.initials: A
authors.lastname: Valls-i-Soler
authors.affiliation: Research Unit for Experimental Neonatal Respiratory Physiology, Cruces University Hospital, Barakaldo, Bizkaia, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Rey-Santano
authors.affiliation: Thermal and Fluids Engineering Division, Mechanical Engineering Department, TECNUN, University of Navarra, San Sebastian, Gipuzkoa, Spain.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Rivas
authors.affiliation: Thermal and Fluids Engineering Division, Mechanical Engineering Department, TECNUN, University of Navarra, San Sebastian, Gipuzkoa, Spain.
authors.forename: Raúl
authors.initials: R
authors.lastname: Antón
authors.affiliation: Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country, Leioa, Bizkaia, Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Basterretxea
authors.affiliation: Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country, Leioa, Bizkaia, Spain.
authors.forename: Lorena
authors.initials: L
authors.lastname: Miñambres
authors.affiliation: Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country, Leioa, Bizkaia, Spain.
authors.forename: Estíbaliz
authors.initials: E
authors.lastname: Méndez
authors.affiliation: Department of Electronics and Electrotechnics, High Technical School of Maritime Studies, University of the Basque Country, Bilbao, Bizkaia, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Lopez-Arraiza
authors.affiliation: Department of Electronics and Electrotechnics, High Technical School of Maritime Studies, University of the Basque Country, Bilbao, Bizkaia, Spain.
authors.forename: Juan Luis
authors.initials: JL
authors.lastname: Larrabe-Barrena
authors.affiliation: Department of Electronics and Electrotechnics, High Technical School of Maritime Studies, University of the Basque Country, Bilbao, Bizkaia, Spain.
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Gomez-Solaetxe
mesh_terms: D000336:Aerosols / Q000008:administration & dosage*; D045422:Continuous Positive Airway Pressure; D016503:Drug Delivery Systems; D005466:Fluorocarbons / Q000008:administration & dosage; D006801:Humans; D008168:Lung / Q000187:drug effects / Q000473:pathology*; D008176:Lung Volume Measurements; D008962:Models, Theoretical; D009330:Nebulizers and Vaporizers; D011663:Pulmonary Surfactants / Q000008:administration & dosage*; D012127:Respiratory Distress Syndrome, Newborn / Q000188:drug therapy* / Q000473:pathology; D012137:Respiratory System / Q000187:drug effects / Q000473:pathology
chemical_list: D000336:Aerosols; D005466:Fluorocarbons; D011663:Pulmonary Surfactants