[Characteristics of pulmonary function changes in cough variant asthma and chronic asthmatic bronchitis]

To understand with greater clearness the characteristics of pulmonary function changes in patients with cough variant asthma (CVA) and patients with chronic asthmatic bronchitis(CAB), 30 cases of CVA and 25 cases of CAB were examined by pulmonary function test and were compared clinically. The results showed the differences in medical history and some clinical manifestations between the two groups were significant (P < 0.05). The expiratory flow parameters (PEF, MMEF, FEV1) of pulmonary function test in CVA were generally normal; these parameters in CAB group, however, were obviously decreased. The airway challenge test uncovered a 100% positive reaction in CVA patients, but only less than 1/4 of the patients with CAB showed positive reaction. Furthermore, the positive concentration of challenge agents (Mch) required for CVA group was 1/4.7 of the ones for CAB group, and the positive Mch concentrations of the two groups seldom crossed each other. It is concluded that some clinical manifestations of CVA and CAB were significantly different, although many similarities between them do exist; the MEFV curve in pulmonary function test and the airway challenge test can be used to differentiate them well.