Airway Responsiveness to Exercise and Ultrasonically Nebulized Distilled Water in Children: Relationship to Clinical and Functional Characteristics

Abstract

We studied the bronchial response to exercise and ultrasonically nebulized distilled water (UNDW) challenge in 19 normal controls (3 females and 16 males; age 6–13 years) and in 44 asthmatic children (12 females and 32 males; age 6–13 years) in order (1) to determine the sensitivity and specificity of the two challenges and (2) to evaluate the relationship between bronchial responses and clinical and functional characteristics. A 20% fall in FEV₁ was regarded as a significant bronchial response. The specificity of both challenges was high (100%), whereas the sensitivity of exercise (77.3%) was twice that of UNDW (38.6%). The combination of the two challenges increased the sensitivity to 81.8%. There was no correlation between the magnitude of bronchial response to exercise and UNDW (r_s = -0.03; p > 0.05). Exercise responders were not different from nonresponders in regard to gender, age, resting lung function, length of asthmatic history and treatment requirement to control symptoms. However, the UNDW responders were different from nonresponders in regard to age (p < 0.05) and length of asthmatic history (p < 0.001). Children younger than 9 years old are unlikely to show a bronchial response to UNDW inhalation, since only 9.5% of them developed a significant bronchoconstriction. We suggest that the two stimuli recognize some different pathways or subjects have basic biological differences.

Bronchial Responsiveness to Inhaled Nonisotonic Solutions in Children with Asthma with Exercise-Induced Broncho-Obstruction

“…5,8,[25][26][27][28][29] Investigators have come to different conclusions regarding the relation between exercise and hypotonic stimulus in patients with asthma. The bronchial responsiveness to exercise was significantly positively correlated with UNDW in studies in 25 adult subjects with atopic asthma 15 and 54 children with asthma, 16 while no correlation was found in four other studies in adults, 17 mixed age group, 13 and children, 18,19 and in present research. Moreover, a significant, but negative correlation (r 5 20.66) between these two stimuli was established in another trial in 25 adults with atopic asthma.…”

“…It is probably that these differences may be related to methodologic differences such as different types of UNDW challenges, the intermittent inhalations in the two last studies. 16,18 and continuous inhalations in the trial by Frisher et al 41 The results of our research indicated that only 14.6% of children with asthma with EIB have the increased bronchial responsiveness to UNDW. We consider that the cause of detection of the lower prevalence of BHR in the present study is combination of use continuously method of UNDW inhalation, as in the trial by Frisher et al, 41 with high criterion for positive response (decrease in FEV 1 grater than or equal to 20%), as in the studies by Foresi et al 18 and Obata and Iikura.…”

“…16,18 and continuous inhalations in the trial by Frisher et al 41 The results of our research indicated that only 14.6% of children with asthma with EIB have the increased bronchial responsiveness to UNDW. We consider that the cause of detection of the lower prevalence of BHR in the present study is combination of use continuously method of UNDW inhalation, as in the trial by Frisher et al, 41 with high criterion for positive response (decrease in FEV 1 grater than or equal to 20%), as in the studies by Foresi et al 18 and Obata and Iikura. 16 In addition, the results of previous study have reported that children younger than 9 years old having history of asthma duration less than 5 years are unlikely to show a bronchial response to inhalation (only in 9.5% of cases).…”

“…[11][12][13][14][15][16][17][18][19][20] Moreover, no research contained results of bronchial responsiveness to all three stimuli in the same patients with asthma. Based on the above data it is not possible to make an implicit conclusion as to the relation between bronchial responsiveness to exercise and nonisotonic solutions.…”

“…In their large group (446 schoolchildren) study, Frisher et al 41 reported a 36% incidence of BHR to inhaled hypotonic solution when a positive bronchial response was defined as a decrease in FEV 1 greater than or equal to 10%. 41 It is surprising that the greater (38.6% and 42.6%) prevalence of increased bronchial response to UNDW was recognized by Foresi et al 18 and Obata and Iikura 16 in trials with lower number (44 and 54, respectively) of children with asthma when a 20% decrease in FEV 1 was suggested as positive response. It is probably that these differences may be related to methodologic differences such as different types of UNDW challenges, the intermittent inhalations in the two last studies.…”