The duration of the operations can represent an important factor for a series of postoperative complications, especially in the aged. OBJECTIVE: study the repercussion in the lungs, of operations of different duration. METHODS: Twenty aged rats (18 months old) and 20 young (3 months old) were randomly separated in groups A and B respectively. The groups were divided in A1, A2, A3, A4, B1, B2, B3 and B4, with five rats each. The animals were anesthetized with pentobarbital (20mg/Kg) intraperitoneal. In the group A1 and B1 a 30 minutes operation was done, in the groups A2 and B2 60 minutes, in the A3 and B3 the operation was done in 120 minutes and in the A4 and B4 control groups the animals were not operated. The procedure consisted of laparotomy that was opened and closed so many times as necessary to reach the operative times. After the 5th postoperative day the animals were killed with anesthetic's overdosis and biopsies of both lungs were performed. The biopsies were processed and colored by HE. The histologic findings were transformed in scores for each group. RESULTS: the following results were seen: The groups of the young rats had the scores: A1= score 6, A2=11; A3=28; A4=5. Old rats had the following scores: B1=12; B2=34; B3=51 e B4=6. The statistical analysis revealed significant difference among the scores of the groups A and B. CONCLUSION: the prolonged time of surgery in rats contributes to significant histopatologic alterations in the lungs. As larger the operative time, larger and more frequent the pulmonary complications.
Pulmonary complications; Aged; Operative time; Aged rats
