[Comparison of sensitivity and specifity of two bronchial provocation tests with methacholine and hypertonic saline in bronchial hyperreactivity evaluation in asthmatics].

UNLABELLED

Bronchial hyperreactivity, a inseparable feature of asthma in polish asthmatics is seldom evaluated. Its depends on at least two causes i.e. a lack of methacholine registration for BPT and an opinion, that challenge test can be harmful or dangerous for patients. That situation could correct wider prevalence of bronchial provocation test with hypertonic saline. To perform the test are needed: spirometer, ultrasonic nebuliser and hypertonic saline. The aim of the study was to compare sensitivity and specifity of both tests with methacholine and hypertonic saline.

MATERIAL AND METHODS

Studies were carried out on a group of 79 subjects, where was 59 asthmatics and 20 healthy subjects (control group). Sensitivity and specifity of both tests were evaluated for a few different thresholds considered as a positive result. Usually a 20% decrease of FEV1 from baseline was considered as positive test result. Three different thresholds were considered for methacholine test i.e. PC20FEV1 = 8,0 or 16,0 or 32,0 mg/ml. Relative to BPT with hypertonic saline maximal inhalation time was constant, i.e. 930s, but different decreases in FEV1 (15% or 20% from baseline) were needed.

RESULTS

The most comparable sensitivity and specifity of the both tests were following, for methacholine threshold = PC20FEV1 = 16 mg/ ml, and for 4,5% NaCl PT15FEV1 = 930s.

CONCLUSION

Although BPT with hypertonic saline is less sensitive than methacholine challenge, it seems to be a good tool to evaluate of bronchial hyperreactivity and should be more often applied.