tailieunhanh - Báo cáo y học: "Airway resistance at maximum inhalation as a marker of asthma and airway hyperresponsiveness"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học 'Respiratory Research cung cấp cho các bạn kiến thức về ngành y đề tài: "Airway resistance at maximum inhalation as a marker of asthma and airway hyperresponsiveness. | Mendonga et al. Respiratory Research 2011 12 96 http content 12 1 96 RESPIRATORY RESEARCH RESEARCH Open Access Airway resistance at maximum inhalation as a marker of asthma and airway hyperresponsiveness Nancy T Mendonga1 Jennifer Kenyon1 Adam S LaPrad1 Sohera N Syeda2 George T O Connor2 and Kenneth R Lutchen1 Abstract Background Asthmatics exhibit reduced airway dilation at maximal inspiration likely due to structural differences in airway walls and or functional differences in airway smooth muscle factors that may also increase airway responsiveness to bronchoconstricting stimuli. The goal of this study was to test the hypothesis that the minimal airway resistance achievable during a maximal inspiration Rmin is abnormally elevated in subjects with airway hyperresponsiveness. Methods The Rmin was measured in 34 nonasthmatic and 35 asthmatic subjects using forced oscillations at 8 Hz. Rmin and spirometric indices were measured before and after bronchodilation albuterol and bronchoconstriction methacholine . A preliminary study of 84 healthy subjects first established height dependence of baseline Rmin values. Results Asthmatics had a higher baseline Rmin predicted than nonasthmatic subjects 134 33 vs. 109 19 predicted p . Sensitivity-specificity analysis using receiver operating characteristic curves indicated that baseline Rmin was able to identify subjects with airway hyperresponsiveness PC20 16 mg mL better than most spirometric indices Area under curve and for Rmin predicted FEV1 predicted and FEF25-75 predicted respectively . Also 80 of the subjects with baseline Rmin 100 predicted did not have airway hyperresponsiveness while 100 of subjects with Rmin 145 predicted had hyperresponsive airways regardless of clinical classification as asthmatic or nonasthmatic. Conclusions These findings suggest that baseline Rmin a measurement that is easier to perform than spirometry performs as well as or better than standard .