Regional Expansion of Oleic Acid-Injured Lungs

Am J Respir Crit Care Med. 1999 Jul;160(1):250-8. doi: 10.1164/ajrccm.160.1.9808101.

Abstract

It has been suggested that dependent regions of an injured lung are collapsed and subject to cyclic reopening and collapse during mechanical ventilation. To test this hypothesis, we measured both temporal and spatial heterogeneity of lobar expansion in oleic acid (OA)-injured dogs. Regional volumes were measured in nine dogs (seven supine and two prone) during closed loop sinusoidal oscillations of the lungs before and after OA injury using the parenchymal marker technique. In contrast to computer tomography, the parenchymal marker technique provides absolute measures of regional tissue dimensions as opposed to relative measures of regional air to liquid content. The experiments generated three major findings: (1) OA injury did not lead to the collapse of dependent lung units at FRC, (2) OA injury did not steepen the vertical gradient in regional lung volumes at FRC, and (3) during sinusoidal oscillation of the OA-injured lungs from FRC, dependent regions did not undergo cyclic reopening and collapse. On the basis of these results, we propose an alternative mechanism for the topographic variability in regional impedances and lung expansion after injury, namely liquid and foam in conducting airways.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Disease Models, Animal
  • Dogs
  • Functional Residual Capacity / drug effects
  • Functional Residual Capacity / physiology
  • Lung / drug effects*
  • Lung / physiopathology
  • Lung Volume Measurements
  • Oleic Acid / toxicity*
  • Positive-Pressure Respiration
  • Pulmonary Alveoli / drug effects
  • Pulmonary Alveoli / physiopathology
  • Pulmonary Atelectasis / chemically induced*
  • Pulmonary Atelectasis / physiopathology
  • Pulmonary Gas Exchange / drug effects
  • Pulmonary Gas Exchange / physiology
  • Respiration, Artificial*
  • Respiratory Mechanics / drug effects
  • Respiratory Mechanics / physiology

Substances

  • Oleic Acid