title: Surfactant increases the uniformity of lung aeration at birth in ventilated preterm rabbits.
abstract: Surfactant deficiency is a major cause of respiratory failure in newborns. We have investigated the roles of surfactant and positive end-expiratory pressure (PEEP) in the development of a functional residual capacity (FRC) and the distribution of ventilation at birth. Preterm rabbit pups (28 d GA) were delivered and received either saline or surfactant and then ventilated with (3PEEP) or without (0PEEP) 3 cm H2O PEEP (groups: saline/0PEEP, surfactant/0PEEP, saline/3PEEP, surfactant/3PEEP). Lung gas volumes were measured using plethysmography, and the uniformity of ventilation was analyzed using phase contrast (PC) x-ray imaging. Surfactant/0PEEP pups had greater FRCs and the lungs were more uniformly ventilated than saline/0PEEP pups; FRC at inflation 19-21 was 2.46 ± 0.52 mL/kg versus 0.91 ± 0.95 mL/kg (p < 0.05). Saline/3PEEP pups developed an FRC of 7.54 ± 1.68 mL/kg at inflation 19-21 (p < 0.05), but the distribution of ventilation was initially nonuniform. Surfactant/3PEEP pups had an FRC of 8.50 ± 0.80 mL/kg (at inflation 19-21), and the distribution of ventilation was more uniform than with saline/3PEEP (p < 0.05). In ventilated preterm newborn rabbits, PEEP has a greater effect on FRC than surfactant, although the two are additive. Surfactant, administered at birth, markedly improved the uniformity of ventilation irrespective of whether PEEP was applied.
authors: Monash Institute of Medical Research, Clayton, Vic 3168, Australia.
authors: Melissa L
authors: ML
authors: Siew
authors: Arjan B
authors: AB
authors: Te Pas
authors: Megan J
authors: MJ
authors: Wallace
authors: Marcus J
authors: MJ
authors: Kitchen
authors: M Sirajul
authors: MS
authors: Islam
authors: Robert A
authors: RA
authors: Lewis
authors: Andreas
authors: A
authors: Fouras
authors: Colin J
authors: CJ
authors: Morley
authors: Peter G
authors: PG
authors: Davis
authors: Naoto
authors: N
authors: Yagi
authors: Kentaro
authors: K
authors: Uesugi
authors: Stuart B
authors: SB
authors: Hooper
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001688:Biological Products / Q000494:pharmacology*; D005652:Functional Residual Capacity / Q000187:drug effects; D005865:Gestational Age; D008168:Lung / Q000000981:diagnostic imaging / Q000187:drug effects*; D008170:Lung Compliance / Q000187:drug effects; D010743:Phospholipids / Q000494:pharmacology*; D010991:Plethysmography; D011175:Positive-Pressure Respiration; D047928:Premature Birth; D011663:Pulmonary Surfactants / Q000494:pharmacology*; D012123:Pulmonary Ventilation / Q000187:drug effects*; D011817:Rabbits; D011859:Radiography; D015656:Respiratory Mechanics / Q000187:drug effects
chemical_list: D001688:Biological Products; D010743:Phospholipids; D011663:Pulmonary Surfactants; C068291:poractant alfa