title: Can bronchodilator response predict bronchial response to methacholine in preschool coughers?
abstract: The aim of the present study was to determine the relationship between bronchodilator response, assessed by interrupter resistance (Rint), and bronchial reactivity in preschool children with chronic cough. Thirty-eight children coughers (median age 5.0 years, range 2.8-6.4) were tested. Bronchodilator response was recorded within 4 months before methacholine challenge. Response to the latter was assessed using transcutaneous partial pressure of oxygen and Rint. Children were considered responders if a 20% fall in transcutaneous partial pressure of oxygen occurred during the bronchial challenge. Bronchodilator response was not different between responders (n = 24) and nonresponders (n = 14) [median (range) -0.11 (-0.44-0.09) vs. -0.08 (-0.21-0.10) kPa L(-1) sec; respectively]. However, none of the nonresponders had a bronchodilator response larger than -0.21 kPa L(-1) sec, this cutoff had a 100% positive and a 44% negative predictive value to predict a positive methacholine challenge. The relationship between bronchodilator response and bronchial methacholine responsiveness reached the limit of significance (P = 0.048). Furthermore, the magnitude of the bronchodilator response was correlated to the level of methacholine-induced level of bronchoconstriction (P = 0.01), and to the postchallenge bronchodilation (P = 0.04), all values expressed as % predicted. Moreover, the postbronchodilator Rint value obtained with preceding methacholine challenge was lower than the postbronchodilator value without preceding methacholine challenge in 71.4% (10/14) of the nonresponders and in only 33.3% (8/24) of the responders. Conclusions in preschool coughers bronchodilator response, assessed by the interrupter technique, was correlated to the bronchial responsiveness to methacholine. Non responders had a bronchodilator response not larger than -0.21 kPa L(-1) sec.
authors.affiliation: AP-HP Robert Debré Hospital, Physiology Department, Paris, France. nicole.beydon@rdb.aphp.fr
authors.forename: Nicole
authors.initials: N
authors.lastname: Beydon
authors.forename: Célestin
authors.initials: C
authors.lastname: M'Buila
authors.forename: Claudine
authors.initials: C
authors.lastname: Peiffer
authors.forename: Agnès
authors.initials: A
authors.lastname: Bernard
authors.forename: Isabelle
authors.initials: I
authors.lastname: Zaccaria
authors.forename: André
authors.initials: A
authors.lastname: Denjean
mesh_terms: D000403:Airway Resistance; D001249:Asthma / Q000175:diagnosis*; D001980:Bronchi / Q000187:drug effects*; D016084:Bronchoconstriction / Q000187:drug effects*; D001993:Bronchodilator Agents / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D003371:Cough; D005260:Female; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D012720:Severity of Illness Index; D013997:Time Factors
chemical_list: D001993:Bronchodilator Agents; D016210:Methacholine Chloride