Establishing functional residual capacity at birth: the effect of sustained inflation and positive end-expiratory pressure in a preterm rabbit model.
The effect of a 20 s sustained inflation (SI) and positive end-expiratory pressure (PEEP) on functional residual capacity (FRC) formation at birth were investigated. Preterm rabbit pups (28 d) were randomized at birth into four groups (n = 6 for each): 1) SI, PEEP 5 cm H2O, 2) no SI, PEEP 5 cm H2O, 3) no SI + no PEEP, 4) SI + no PEEP. FRC and tidal volume (Vt) were measured by plethysmography and uniformity of lung aeration by phase contrast x-ray imaging. Ventilation with a SI and PEEP uniformly aerated the lung and Vt and FRC were recruited by the first tidal inflation. Ventilation without a SI, with PEEP, gradually recruited Vt and FRC with each inflation but aeration was not uniform. Ventilation without a SI or PEEP, gradually recruited Vt, but no FRC. Ventilation with a SI, without PEEP, uniformly aerated the lung and recruited Vt but no FRC. FRC was greater with SI (p = 0.006) during the first minute, but was larger with PEEP than without PEEP throughout the first 7 min (p < 0.0005). Effects of PEEP and SI were additive. In ventilated preterm rabbits at birth, combining a SI and PEEP improved FRC formation and uniformity of lung aeration, but PEEP had the greatest influence.
te Pas
Arjan B
AB
Neonatal Services, Royal Women's Hospital, Melbourne, Victoria 3052, Australia. a.b.te_pas@lumc.nl
Siew
Melissa
M
Wallace
Megan J
MJ
Kitchen
Marcus J
MJ
Fouras
Andreas
A
Lewis
Robert A
RA
Yagi
Naoto
N
Uesugi
Kentaro
K
Donath
Susan
S
Davis
Peter G
PG
Morley
Colin J
CJ
Hooper
Stuart B
SB
D000818:Animals; D000831:Animals, Newborn; D005652:Functional Residual Capacity; D005865:Gestational Age; D008168:Lung / Q000000981:diagnostic imaging / Q000503:physiopathology*; D023421:Models, Animal; D010991:Plethysmography; D011175:Positive-Pressure Respiration; D047928:Premature Birth / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D012123:Pulmonary Ventilation; D011817:Rabbits; D011859:Radiography; D012121:Respiration, Artificial / Q000379:methods*; D013990:Tidal Volume; D013997:Time Factors