Purpose To find out a simple, chief, standard & easily available agent for bronchoprovocation & also to determine the provocating dose of hypertonic saline, which will reduce at least 20% of FEV1 in bronchial asthma patient.
Methods A prospective case control study was carried out among 50 patients with bronchial asthma and 50 normal healthy control at Asthma centre in NIDCH, Bangladesh. Hypertonic saline of different concentration in doubling doses (1.8%, 3.6%, 7.2%), sequentially from lower to higher concentration was inhaled to both group by nebuliser and the test was terminated when drop of at least 20% FEV1 had occurred. Patients were selected according to prefixed inclusion & exclusion criteria. Structured questionnaire was filled-up by each patient. Written consent was taken from every patient & control after proper explanation about the procedure & its outcome.
Results In the control group M/F ratio was 1.27:1, age ranged from 11 years to 50 years and of 5 different occupations (student, service holder, businessman, housewife and worker). In patient group M:F was 1.38:1, age range from 11 to 50 years and five different occupation was same as control. There were no statistically significant differences between the two groups regarding age, sex and occupation. In control, graded amount of hypertonic saline (1.8%, 3.6%, 7.2%) was given by nebuliser inhalation. None of them showed fall of FEV1 significantly (20%). But in patient group, with similar concentration of hypertonic saline inhalation, there was highly significant fall in FEV1, χ2 test showed highly significant value, χ2=75.42 and p<0.001.
Conclusion Hypertonic saline induced broncho provocation is actually very safe, simple & cheap. So the people of third world countries can afford this test in minimum cost. Provocative dose of Hypertonic saline is 7.2% (20% fall of FEV1).
Clinical implications For the diagnosis of cough variant asthma & also in the suspected cases of bronchial asthma, we can performed this test confidently.