title: Feasibility and short-term effects of biphasic positive airway pressure versus assist-control ventilation in preterm lambs.
abstract: Biphasic positive airway pressure (BiLevel) ventilation allows utilization of two alternating positive end-expiratory pressures (PEEP) while permitting unrestricted spontaneous breathing with superimposed synchronized pressure support. We aimed to compare whether BiLevel versus assist-control (A-C) ventilation provides effective gas exchange and reduces severity of early lung injury in preterm lambs. Preterm lambs delivered at 134 d (term = 150 d) were quasirandomized to BiLevel (PEEP low/high 5/20 cm H2O) or A-C5 (PEEP 5 cm H2O) ventilation. Ventilation parameters and arterial blood gases were recorded at regular intervals. Postmortem measurements included pressure-volume relationship, lung inflammatory score, wet/dry body weight ratio, and messenger RNA (mRNA) expression of early markers of lung injury. There were no significant differences between groups in baseline characteristics, oxygenation index (p = 0.49), or partial pressure of carbon dioxide (Paco2) (p = 0.08). BiLevel group lambs showed improved pressure-volume relationship (p = 0.006), lower lung inflammatory score (p = 0.013), and trend toward lower messenger RNA expression of markers of lung injury compared with A-C5 group lambs. In unsedated preterm lambs, BiLevel ventilation provides gas exchange equivalent to A-C ventilation and potentially results in reduced lung injury.
authors.affiliation: School of Women's and Infant's Health, University of Western Australia, Crawley, Western Australia 6009, Australia. sven.schulzke@health.wa.gov.au
authors.forename: Sven M
authors.initials: SM
authors.lastname: Schulzke
authors.forename: Graeme R
authors.initials: GR
authors.lastname: Polglase
authors.forename: Foula
authors.initials: F
authors.lastname: Sozo
authors.forename: J Jane
authors.initials: JJ
authors.lastname: Pillow
mesh_terms: D000818:Animals; D045422:Continuous Positive Airway Pressure / Q000379:methods*; D055370:Lung Injury / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D016133:Polymerase Chain Reaction; D047928:Premature Birth; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D012756:Sheep
chemical_list: D012333:RNA, Messenger