Lack of a late asthmatic response after hypertonic saline challenge in children

Hypertonic saline challenge has become a standardized method for measuring airway responsiveness. However, there is still uncertainty about the occurr ence of a late asthmatic response. Therefore, the present study was designe d to assess a possible late asthmatic response after hypertonic saline chal lenge in children. Twenty-one children with mild to moderate bronchial hyperresponsiveness wer e studied. On days 1 and 2, forced expiratory volume in one second (FEV1) w as measured hourly from 10:00 h to 22:00 h to assess diurnal variation of l ung function. On the third study day, a hypertonic saline challenge was per formed and FEV1 was measured as on control days. The possibility of a late asthmatic response was tested by comparing FEV1 levels up to 12 h after the challenge on the intervention day to FEV1 levels on control days. In no subjects were the FEV1 values following the challenge found to be con siderably below the individual mean of the control days. Furthermore, a non parametric approach was applied for each child and the population looked in to as a whole. Again, no late asthmatic response was detectable. The results of this study suggest that in children with mild to moderate br onchial hyperresponsiveness a late asthmatic response does not occur 4-12 h after a 4.5% saline challenge.