An animalmodel was used to study the effects of normobaric hyperoxia on pulmonary mechanics and histopathology. Thirty two rats (227(46gm) were divided into control (Group 1) in room air and 3 hyperoxic groups (n=8, each) Hyperoxic groups
breathed
F1O2
( 0.98 for 24 hr(group 2), 48 hr(group 3), and 72 hr(group 4), respectively. After hyperoxia, rats were intubated through tracheostomy, and inflation and deflation compliances of lung-thorax [CLT(I), CLT(D)] were calculated. Body weight(BW) was
measured, and lungs were removed and weighed(LW). The lung specimens were examined microscopically.
At the 3rd day of hyperoxia, 5 of 8 rats were died (63% mortality). CLT(I) of Group 4 was low (p<0.05) compared with others. And CLT(D) of all hyperoxic groups were low (p<0.05) compared with control. Mean LW/BW (lung weight divided by body
weight)
was
elevated (p<0.05) in Group 3 and Group 4. Pulmonary pathologic findings such as inflammation, congestion, alveolar andbronchial wall damgae, pulmonary edema etc. became apparent (p<0.05) at the 3rd day.
We conclude that during hyperoxia pulmonary compliance might be decreased and lung weight might be increased progressively, and pulmonary pathological appearance of normobaric hyperoxia (F1O2 ( 0.98) resemble those of adult respiratory distress
syndrome
(ARDS).
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