title: Effect of surfactant on regional lung function in an experimental model of respiratory distress syndrome in rabbit.
abstract: We assessed the changes in regional lung function following instillation of surfactant in a model of respiratory distress syndrome (RDS) induced by whole lung lavage and mechanical ventilation in eight anaesthetized, paralyzed, and mechanically ventilated New Zealand White rabbits. Regional specific ventilation (sV̇) was measured by K-edge subtraction synchrotron computed tomography during xenon washin. Lung regions were classified as poorly aerated (PA), normally aerated (NA), or hyperinflated (HI) based on regional density. A functional category was defined within each class based on sV̇ distribution (High, Normal, and Low). Airway resistance (Raw), respiratory tissue damping (G), and elastance (H) were measured by forced oscillation technique at low frequencies before and after whole lung saline lavage-induced (100 ml/kg) RDS, and 5 and 45 min after intratracheal instillation of beractant (75 mg/kg). Surfactant instillation improved Raw, G, and H (P < 0.05 each), and gas exchange and decreased atelectasis (P < 0.001). It also significantly improved lung aeration and ventilation in atelectatic lung regions. However, in regions that had remained normally aerated after lavage, it decreased regional aeration and increased sV̇ (P < 0.001) and sV̇ heterogeneity. Although surfactant treatment improved both central airway and tissue mechanics and improved regional lung function of initially poorly aerated and atelectatic lung, it deteriorated regional lung function when local aeration was normal prior to administration. Local mechanical and functional heterogeneity can potentially contribute to the worsening of RDS and gas exchange. These data underscore the need for reassessing the benefits of routine prophylactic vs. continuous positive airway pressure and early "rescue" surfactant therapy in very immature infants.
authors.affiliation: Université de Picardie Jules Verne, Inserm U1105 and Pediatric Lung Function Laboratory, Amiens University Hospital, Amiens, France; bayat.sam@chu-amiens.fr.
authors.forename: Sam
authors.initials: S
authors.lastname: Bayat
authors.affiliation: Department of Physics, University of Helsinki, and Helsinki University Central Hospital, Helsinki, Finland;
authors.forename: Liisa
authors.initials: L
authors.lastname: Porra
authors.affiliation: Université de Picardie Jules Verne, Inserm U1105 and Pediatric Lung Function Laboratory, Amiens University Hospital, Amiens, France; European Synchrotron Radiation Facility, Biomedical Beamline-ID17, Grenoble, France;
authors.forename: Ludovic
authors.initials: L
authors.lastname: Broche
authors.affiliation: Anesthesiological Investigation Unit, University of Geneva, Geneva, Switzerland;
authors.forename: Gergely
authors.initials: G
authors.lastname: Albu
authors.affiliation: Anesthesiological Investigation Unit, University of Geneva, Geneva, Switzerland;
authors.forename: Iliona
authors.initials: I
authors.lastname: Malaspinas
authors.affiliation: Anesthesiological Investigation Unit, University of Geneva, Geneva, Switzerland;
authors.forename: Camille
authors.initials: C
authors.lastname: Doras
authors.affiliation: Department of Physics, University of Helsinki, and Helsinki University Central Hospital, Helsinki, Finland;
authors.forename: Satu
authors.initials: S
authors.lastname: Strengell
authors.affiliation: Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary; and.
authors.forename: Ferenc
authors.initials: F
authors.lastname: Peták
authors.affiliation: Anesthesiological Investigation Unit, University of Geneva, Geneva, Switzerland; Geneva Children's Hospital, University Hospitals of Geneva and Geneva University, Geneva, Switzerland.
authors.forename: Walid
authors.initials: W
authors.lastname: Habre
mesh_terms: D000403:Airway Resistance / Q000187:drug effects; D000818:Animals; D001688:Biological Products / Q000008:administration & dosage*; D004195:Disease Models, Animal; D007322:Instillation, Drug; D008168:Lung / Q000187:drug effects / Q000503:physiopathology*; D008297:Male; D011659:Pulmonary Gas Exchange / Q000187:drug effects*; D011663:Pulmonary Surfactants; D011817:Rabbits; D012128:Respiratory Distress Syndrome / Q000188:drug therapy / Q000503:physiopathology*; D015656:Respiratory Mechanics / Q000187:drug effects*; D007507:Therapeutic Irrigation; D016896:Treatment Outcome
chemical_list: D001688:Biological Products; D011663:Pulmonary Surfactants; C072197:beractant
keywords: X-ray computed; pulmonary surfactants; respiratory distress syndrome; respiratory mechanics; synchrotrons; tomography; xenon