Methacholine vs adenosine on intra and extrathoracic airway hyperresponsiveness in patients with cough variant asthma.

摘要: Background:  Airway hyperresponsiveness (AHR) can be studied by bronchoprovocation test (BPT) using direct (methacholine – MCh) or indirect (adenosine 5′-monophosphate AMP) stimuli. These two substances have not been compared in cough variant asthma (CVA). Objective:  We designed a randomized, single-blind, cross-over study to compare AMP and MCh the detection of CVA. Additionally, we examined whether assessment extrathoracic airway (EAHR) during helped evaluation CVA. Methods:  Patients with CVA previous positive BPT performed challenges MCh. The variables were: (i) provocative dose producing 20% fall forced expiratory volume 1 s (FEV1) value (PD20MCh); (ii) 25% maximal mid-inspiratory flow (FIF50) from baseline (PD25MCh) for MCh; (iii) concentration FEV1 (PC20AMP) (iv) FIF50 (PC25AMP) AMP. Results:  All 113 patients responded PD20MCh 96% 69% PC20AMP, if used PC20 ≤ 200 mg/ml PC20 ≤ 100 mg/ml, respectively, an excellent correlation between these tests (r = 0.87 0.76, respectively). Extrathoracic AHR associated was found 10% challenge 11% no had EAHR alone. Conclusion:  Adenosine correlate well A minority (c. 10%) as measured tests, while most assessed each agents.