Effect of different pressure levels on the dynamics of lung collapse and recruitment in oleic-acid-induced lung injury

Am J Respir Crit Care Med. 1998 Nov;158(5 Pt 1):1636-43. doi: 10.1164/ajrccm.158.5.9711095.


The effects of different inspiratory and expiratory airway pressures (Paw) on the dynamics of lung collapse and recruitment were studied in 14 anesthetized, mechanically ventilated, pigs with oleic-acid-induced lung injury. Repetitive CT scans of the same slice were obtained every 0.8 s during different inspiration and expiration hold procedures. The mean lung density and amount of atelectasis were measured in each scan. Inspiration to a Paw of 15 cm H2O above PEEP resulted in recruitment of collapsed lung tissue, mainly within 1.4 s. During expiration lung density increased rapidly and at an almost even rate within the first 1.4 s, whereas a rapid increase of atelectasis occurred after an initial delay period of 0.6 s with PEEP = 10 or 15 cm H2O. PEEP of 20 or 25 cm H2O almost prevented lung collapse during expiration. Thus, in order to avoid cyclic alveolar collapse during mechanical ventilation in oleic-acid-induced lung injury, a PEEP level >= 20 cm H2O or an expiration time <= 0.6 s is required. Long inspiratory time intervals, as used in inverse ratio ventilation, seem to be of minor importance for the recruitment of collapsed lung tissue in this experimental model.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Animals
  • Disease Models, Animal
  • Image Processing, Computer-Assisted
  • Inspiratory Capacity / physiology
  • Lung / diagnostic imaging
  • Lung / physiopathology*
  • Oleic Acid / adverse effects
  • Positive-Pressure Respiration / methods
  • Pressure
  • Pulmonary Atelectasis / diagnostic imaging
  • Pulmonary Atelectasis / physiopathology*
  • Pulmonary Atelectasis / prevention & control
  • Pulmonary Atelectasis / therapy
  • Pulmonary Gas Exchange / physiology
  • Pulmonary Ventilation / physiology*
  • Respiration
  • Respiratory Distress Syndrome / diagnostic imaging
  • Respiratory Distress Syndrome / physiopathology*
  • Respiratory Distress Syndrome / therapy
  • Swine
  • Tidal Volume / physiology
  • Time Factors
  • Tomography, X-Ray Computed
  • Ventilation-Perfusion Ratio / physiology


  • Oleic Acid