|
Simultaneous measurement of airway resistance and maximal expiratory flow-volume loop was performed in 20 asthmatics, 20 emphysema-chronic bronchitis patients and 10 normal control subjects. The airway resistance was both increased in asthma and in emphysema-chronic bronchitis. While the degree of decrease in the parameters of expiratory flow rate was not different in both conditions, airway resistance was significantly higher in asthma than in emphysema-chronic bronchitis. The mean age of asthmatics was younger than that of emphysema-chronic bronchitis. (47.5 vs 59.9) But there was no relationship between age and airway resistance in control group, which, excludes age as a contributing factor(r=-0.18). There was significant co-relation between Raw and FEVl/FVC, MEF 50% in asthmatics (r=-0.60, -0.67) than in emphysema-chronic bronchitis patients (r=-0.03, -0.20). In control group, the corelation between Raw and FEVl/FVC was fairly good (r=-0.57), whereas corelation with MEF 50% was much poorer(r=-0.13), reflecting that the airway resistance is determined mainly by large airways, not by small airways. The Gaw, reciprocal of Raw, showed slightly poorer corelation with parameters of expiratory flow limitation than Raw except in control group, reminding the previous finding that there can to more error in measurement of Gaw than Raw. The two cases of emphysema-chronic bronchitis patients with positive bronchodilator responce displayed higher Raw, suggesting that the measurement of Raw could to used as a predictor of bronchodilator responce.
|