Absence of alveolar tears in rat lungs with significant alveolar instability

Lucio A. Pavone, Joseph D. DiRocco, David E. Carney, Louis A. Gatto, Nils Tomas D. McBride, Jillian A. Norton, Richard M. Hession, Francoise Boubert, Katy A. Hojnowski, Ryan L. LaFollette, David J. Dries, Gary F. Nieman

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

Background: Lung injury associated with the acute respiratory distress syndrome can be exacerbated by improper mechanical ventilation creating a secondary injury known as ventilator-induced lung injury (VILI). We hypothesized that VILI could be caused in part by alveolar recruitment/derecruitment resulting in gross tearing of the alveolus. Objectives: The exact mechanism of VILI has yet to be elucidated though multiple hypotheses have been proposed. In this study we tested the hypothesis that gross alveolar tearing plays a key role in the pathogenesis of VILI. Methods: Anesthetized rats were ventilated and instrumented for hemodynamic and blood gas measurements. Following baseline readings, rats were exposed to 90 min of either normal ventilation (control group: respiratory rate 35 min-1, positive end-expiratory pressure 3 cm H2O, peak inflation pressure 14 cm H2O) or injurious ventilation (VILI group: respiratory rate 20 min-1, positive end-expiratory pressure 0 cm H2O, peak inflation pressure 45 cm H2O). Parameters studied included hemodynamics, pulmonary variables, in vivovideo microscopy of alveolar mechanics (i.e. dynamic alveolar recruitment/derecruitment) and scanning electron microscopy to detect gross tears on the alveolar surface. Results: Injurious ventilation significantly increased alveolar instability after 45 min and alveoli remained unstable until the end of the study (electron microscopy after 90 min revealed that injurious ventilation did not cause gross tears in the alveolar surface). Conclusions: We demonstrated that alveolar instability induced by injurous ventilation does not cause gross alveolar tears, suggesting that the tissue injury in this animal VILI model is due to a mechanism other than gross rupture of the alveolus.

Original languageEnglish (US)
Pages (from-to)439-446
Number of pages8
JournalRespiration
Volume74
Issue number4
DOIs
StatePublished - Jul 1 2007
Externally publishedYes

Keywords

  • Acute respiratory distress syndrome
  • Microvascular fracture
  • Recruitment/derecruitment
  • Ventilator-induced lung injury

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine

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    Pavone, L. A., DiRocco, J. D., Carney, D. E., Gatto, L. A., McBride, N. T. D., Norton, J. A., Hession, R. M., Boubert, F., Hojnowski, K. A., LaFollette, R. L., Dries, D. J., & Nieman, G. F. (2007). Absence of alveolar tears in rat lungs with significant alveolar instability. Respiration, 74(4), 439-446. https://doi.org/10.1159/000101476