Bronchial hyperresponsiveness to hypertonic saline challenge in children and adolescents

To assess airway hyperresponsiveness to 4.5% hypertonic saline solution in comparison to that obtained through challenge with other bronchoconstriction agents and in relation to patient allergic sensitization.

A cross-sectional, experimental study was conducted, initially involving 85 subjects. After exclusions, the final sample consisted of 62 patients, divided into two groups: a study group of those with asthma (n = 45) and a control group of those with no asthma or allergies (n = 17). Hypertonic saline was nebulized using an ultrasonic nebulizer and administered successively for 0.5, 1, 2, 4 and 8 minutes until a drop in forced expiratory volume in one second of = 15% was achieved in relation to the baseline value. The level of specific immunoglobulin E to Dermatophagoides pteronyssinus level was determined by ImmunoCAP assay and was considered positive when > 0.35 kU/L.

In the 36 asthma group subjects presenting a response, the mean drop in forced expiratory volume in one second after hypertonic saline nebulization was 27.4%. None of control group subjects (immunoglobulin E < 0.35 kU/L) presented a positive response to hypertonic saline. The mean forced expiratory volume in one second for control group subjects was 9%. The results of a bronchial provocation test were negative in 9 of the asthma group subjects. The frequency of bronchial provocation test positivity was higher in the subjects presenting elevated levels of specific immunoglobulin E, indicating that there is a relationship between bronchial hyperresponsiveness and the level of specific immunoglobulin E. The sensitivity and specificity of the test were 80% and 92%, respectively.

Bronchial provocation with hypertonic saline presents satisfactory sensitivity and specificity. Therefore, in addition to being a low cost procedure that requires very little equipment, it is a useful means of assessing hyperresponsiveness in children and adolescents.