RT Journal Article
SR Electronic
T1 Predictive factors of a positive methacholine challenge response based on data from a baseline respiratory function test
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP PA609
DO 10.1183/13993003.congress-2015.PA609
VO 46
IS suppl 59
A1 Rute Morgado
A1 Cátia Oliveira
A1 Rafaela Campanha
A1 Susana Moreira
A1 Richard Staats
A1 Dina Escaleira
A1 João Valença
A1 Cristina Bárbara
YR 2015
UL http://erj.ersjournals.com/content/46/suppl_59/PA609.abstract
AB Airway hyperresponsiveness (AHR) is defined as an excessive response to an aerosolized drug provocation that elicits little or no response in a normal person. The methacholine (MCH) challenge is a method of assessing AHR, which is one of the features that contributes to the diagnosis of asthma. However, MCH challenge has some handicaps: high economic costs, a complex process of preparation, a limited availability of the drug and a long evaluation time with a qualified technician.The aim of this study was to identify the predictive factors of a positive MCH challenge based on the data from a baseline respiratory function test.Between 2011 and 2015, a total of 447 patients underwent MCH challenge test (equipment: Masterscreen VIASYS with APS) after performing a baseline respiratory function test (according to the criteria of the ATS 1999). The test was considered positive when the result of the PD20 was between < 0,1 µmol and 7.8 µmol. The statistic significance was evaluated with the T-test.A positive MCH challenge, based on ATS FEV1 criteria, was observed in 252 subjects (56,4%). A positive MCH challenge correlated statistically with age (p=0,000), FEV1% (p=0,001), FEF50% (p=0,001), RV% (p=0,049) and airway resistance Raw (p=0,005). On the other side, lung inflation and specific conductance sGaw had no correlation with the MCH challenge.The predictive factors of a positive response to a MCH challenge are extremely important, since they may be the base of future guidelines to identify the patients that will benefit from this test. This will allow a rationale use of a complex and expensive resource with an improvement in the healthcare efficiency.