title: Effect of sustained inflation length on establishing functional residual capacity at birth in ventilated premature rabbits.
abstract: The effect of inflation length on lung aeration pattern, tidal volumes, and functional residual capacity (FRC) immediately after birth was investigated. Preterm rabbits (28 d), randomized into four groups, received a 1-, 5-, 10-, or 20-s inflation (SI) followed by ventilation with 5 cm H2O end-expiratory pressure. Gas volumes were measured by plethysmography and uniformity of lung aeration by phase contrast x-ray imaging for 7 min. The first inspiratory volume significantly (p < 0.001) increased with inflation duration from a median (IQR) of 0.2 (0.1-3.1) mL/kg for 1-s inflation to 23.4 (19.3-30.4) mL/kg for 20-s SI. The lung was uniformly aerated, and the FRC and tidal volume fully recruited after 20-s SI. A 10-s SI caused a higher FRC (p < 0.05) at 7 min, and a 20-s SI caused a higher FRC (p < 0.05) at 20 s and 7 min than a 1- or 5-s SI. The mean (SD) time for 90% of the lung to aerate was 14.0 (4.1) s using 35 cm H2O peak inflation pressure. In these rabbits, 10- and 20-s SI increased the inspiratory volume and produced a greater FRC, and a 20-s SI uniformly aerated the lung before ventilation started.
authors: Neonatal Services, Royal Women's Hospital, Parkville, Victoria 3053, Australia. a.b.te_pas@lumc.nl
authors: Arjan B
authors: AB
authors: te Pas
authors: Melissa
authors: M
authors: Siew
authors: Megan J
authors: MJ
authors: Wallace
authors: Marcus J
authors: MJ
authors: Kitchen
authors: Andreas
authors: A
authors: Fouras
authors: Robert A
authors: RA
authors: Lewis
authors: Naoto
authors: N
authors: Yagi
authors: Kentaro
authors: K
authors: Uesugi
authors: Susan
authors: S
authors: Donath
authors: Peter G
authors: PG
authors: Davis
authors: Colin J
authors: CJ
authors: Morley
authors: Stuart B
authors: SB
authors: Hooper
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000033:anatomy & histology / Q000502:physiology*; D005652:Functional Residual Capacity / Q000502:physiology*; D006801:Humans; D001239:Inhalation / Q000502:physiology*; D007327:Insufflation; D008168:Lung / Q000000981:diagnostic imaging / Q000502:physiology; D008176:Lung Volume Measurements; D010991:Plethysmography; D047928:Premature Birth; D011817:Rabbits; D011859:Radiography; D011897:Random Allocation; D012121:Respiration, Artificial / Q000009:adverse effects / Q000379:methods*; D015656:Respiratory Mechanics; D013990:Tidal Volume