[Assessment of exercise test and bronchial reversibility test as tools for asthma diagnosis in patients with normal spirometry].

Unlabelled: The bronchial obturation reversibility test is the corner stone in asthma diagnosis. Patients with signs and symptoms suggestive of asthma but normal spirometry need additional tests like non-specific bronchoprovocations. Exercise-induced bronchi spasm is a feature of asthma and is the basis for exercise-test bronchi provocation in asthma diagnosis. The aim of this study was the comparison of clinical utility of obturation reversibility test and exercise provocation test in asthma diagnosis in patients with normal spirometry values.
Methods and Material: The study was comprised of 77 subjects: 47 suspected to have asthma on history and 30 healthy volunteers. The inclusion criterion was: normal spirometry values. The obturation reversibility test was carried out in the study group. All participants had exercise test based on bicycle ergometer. The burden was adjusted so that the heart rate was at the submaximal level throughout the whole procedure. Spirometry values and peak expiratory flow (mini-Wright meter) were measured right after completion of the test and 5, 10, 15 and 20 minutes after completion of the test. The exercise test was considered positive when FEV1 declined by 15% or PEF declined by 20% in comparison to the initial value, respectively.
Results: The obturation reversibility test was positive in 15 (31.9%) and negative in 32 (68.1%) patients from the study group. In the study group exercise test was positive according to FEV1 decline in 35 (74.5%) subjects, and only in 18 (38.3%) if PEF decline was a criterion. In the control group just 1 (3.3%) test turned out positive by FEV1 change and 3 (10%) were positive if PEF decline was measured. On the basis of positive exercise test and patient history the diagnosis of bronchial asthma was established in 35 (74.4%) patients. Among them--24 had sporadic asthma, 8 mild chronic asthma and 3 moderate chronic asthma.
Conclusions: 1. Exercise test is a valuable diagnostic tool in patients with history suggestive of asthma and normal spirometry results and negative obturation reversibility test. 2. The parameter for the exercise test that best separate asthma and control group was FEV1.