Establishing Functional Residual Capacity at Birth: The Effect of Sustained Inflation and Positive End-Expiratory Pressure in a Preterm Rabbit Model

Pediatr Res. 2009 May;65(5):537-41. doi: 10.1203/PDR.0b013e31819da21b.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Functional Residual Capacity*
  • Gestational Age
  • Lung / diagnostic imaging
  • Lung / physiopathology*
  • Models, Animal
  • Plethysmography
  • Positive-Pressure Respiration*
  • Premature Birth / diagnostic imaging
  • Premature Birth / physiopathology
  • Premature Birth / therapy*
  • Pulmonary Ventilation*
  • Rabbits
  • Radiography
  • Respiration, Artificial / methods*
  • Tidal Volume
  • Time Factors