Nitrogen Dioxide-Induced Acute Lung Injury in Sheep
Abstract
Lung mechanics, hemodynamics and blood chemistries were assessed in sheep before, and up to 24 h after, a 15-20 min exposure to either air (control) or 500 ppm nitrogen dioxide (NO2). Nose-only (NO) and lung-only (LO) routes of exposure were compared for effects on NO2 pathogenesis. Bronchoalveolar lavage fluids (BALF) from exposed sheep were analyzed for biochemical/cellular signs of NO2 insult. The influence of breathing pattern on NO2 dose was also assessed. NO2 exposure of intubated sheep (LO exposure) was marked by a statistically significant blood methemoglobin increase. The exposure induced an immediate tidal volume decrease, and an increase in both breathing rate and inspired minute ventilation. Pulmonary function, indexed by lung resistance (RL) and dynamic lung compliance (Cdyn), progressively deteriorated after exposure. Maximal RL and Cdyn, changes occurred at 24 h post exposure, concomitant with arterial hypoxemia. BALF epithelial cell number and total protein significantly increased while macrophage number significantly decreased within the 24-h post- exposure period. Examination of lung tissue 24 after NO2 revealed patchy edema, mild hemorrhage and polymorphonuclear and mononuclear leukocyte infiltration. The NO2 toxicologic profile was significantly attenuated when sheep were exposed to the gas through a face mask (No exposure). Sheep, Nitrogen dioxide, Lung mechanics, Hemodynamics, Bronchoalveolar lavage
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1994
- Accession Number
- ADA283970
Entities
People
- A. J. Januszkiewicz
- M. A. Mayorga
Organizations
- Walter Reed Army Institute of Research