The Pathophysiologic Effects of Hyperoxia on the Lung in Rats. |
Jae Hyon Bahk, Seong Deok Kim |
1Department of Anesthesiology, Samsung Medical Center, Seoul, Korea. 2Department of Anesthesiology, College of Medicine, Seoul National University, Seoul, Korea. |
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Abstract |
An animal model 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 and bronchial wall damage, 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). |
Key Words:
Hyperoxia; Lung; Rat; Compliance; Pathology |
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