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Examination of induced sputum and measurement of exhaled NO have been advocated as noninvasive methods of assessing the degree of airway inflammation. In this study, we performed follow-up evaluation on 71 subjects with asthma caused by exposure to Western red cedar; 50 subjects had left exposure, whereas the rest continued to work in the same job. Spirometry, methacholine challenge tests, exhaled nitric oxide, and sputum induction were carried out. Of the 50 subjects who left exposure, 12 had no respiratory impairment according to the American Throacic Society guidelines for assessing respiratory impairment in patients with asthma, 17 belonged to Class 1, 12 to Class 2, five to Class 3, and four to Class 4. The percentage of eosinophils in induced sputum showed a significant inverse relationship with FEV1 (r = -0.46, p0.001), and a significant positive correlation with levels of exhaled NO (r = 0.42, p0.001) and with the class of respiratory impairment (r = 0.52, p0.001). Mean percent eosinophils were 1.5 for impairment Class 0, 2.2 for Class 1, 1.7 for Class 2, 6.8 for Class 3, and 16.3 for Class 4. No relationship was found between the levels of exhaled NO and the functional parameters as well as the impairment class. NO levels in ppb were 21 for impairment Class 0, 30 for Class 1, 22 for Class 2, 26 for Class 3, and 49 for Class 4. This study also provides objective evidence that airway inflammation, as indicated by induced sputum, corroborates the rating of respiratory impairment in patients with asthma.

We conducted a prospective study to evaluate whether lack of an adequate increase in diffusing capacity for carbon monoxide (DL(CO)) during exercise is associated with a greater postoperative complication rate after lung resection. We used the three-equation method (3EQ-DL(CO)), a modification of the single breath DL(CO) technique to determine DL(CO) during exercise in 57 patients undergoing lung resection at Vancouver General Hospital from October 1998 to May 1999. 3EQ-DL(CO) was determined during steady-state exercise at 35% and 70% of the maximal workload reached in a progressive exercise test. Maximal oxygen uptake (VO(2)max), DL(CO) at rest, and the increase in DL(CO) during exercise were compared in relation to postoperative complications. Patients with complications had lower resting values of DL(CO) (R-DL(CO)), a smaller increase in DL(CO) from rest to 70% of maximal workload expressed as a percent of the predicted DL(CO) at rest ([70% - R]-DL(CO)%), and a lower VO(2)max than did patients without complications. Results suggested that (70% - R)-DL(CO)% was the best preoperative predictor of postoperative complications; a cutoff limit of 10% was the best index to identify complications, yielding a complication rate of 100% in patients with (70% - R)-DL(CO)%10% as compared with a complication rate of 10% in patients with (70% - R)-DL(CO)%/= 10% (sensitivity = 78%, specificity = 100%). Patients who do not increase their DL(CO) sufficiently during exercise ([70% - R]-DL(CO)%10%) have a greater complication rate after lung resection.