IDIOPATHIC PULMONARY FIBROSIS AND ANESTHESIA - THE POSSIBLE RISK OF OXYGEN ADMINISTRATION

We studied the effects of a low oxygen concentration (less than 50%) d uring the induction of and the emergence from general anesthesia on th e postoperative course of patients with idiopathic pulmonary fibrosis (IPF), Fifteen of 30 patients who had open lung biopsies between May 1 990 and March 1994 were anesthetized with a low FIO2 (<0.50) (Group A) , while the other 15 patients received 100% oxygen (Group B), To evalu ate the postoperative state, we used the ratio of the postoperative to the preoperative serum level of lactate dehydrogenase (post/pre LDH) and the number of days oxygen assistance was needed after operation, I n addition, the following risk factors were also considered: age over 60 years, heavy smoking (a smoking index of more than 600), and a seru m level of preoperative LDH higher than 400 IU/l. The post/pre LDH was similar in the two groups (Group A 1.060 +/- 0.148; Group B 1.079 +/- 0.177, not significant), Group A patients needed fewer days of oxygen assistance after operation than did Group B patients (5.6 +/- 4.1 vs 12.8 +/- 12.3; P = 0.0426), The number of days using oxygen assistance after operation was: in the elderly, 5.0 +/- 1.7 in Group A, 11.8 +/- 2.0 in Group B (P = 0.0236); in heavy smokers, 5.2 +/- 1.2 in Group A , 11.5 +/- 2.2 in Group B (P = 0.0383); and in the high LDH groups, 4. 7 +/- 1.1 in Group A, 19.0 +/- 7.5 in Group B (P = 0.0483). We thus co nclude that even such a short exposure to highly concentrated oxygen m ay affect the postoperative course. Therefore, anesthesia with low oxy gen inhalation is recommended because it is simple and poses no risk t o the patients.