Comparison of bronchodilator response in patients with asthma and healthy subjects using spirometry and oscillometry.

Impulse oscillometry (IOS) is an effort-independent and patient-friendly pulmonary function technique, but limited data are available that correlate the bronchodilator response using spirometry and IOS in adult asthmatic and healthy subjects. To compare spirometry and IOS in ongoing bronchodilator response. The study was a prospective evaluation of patients with asthma and healthy subjects attending screening at a research unit in a university teaching hospital. Reversibility testing was carried out using standardized American Thoracic Society/European Respiratory Society (ATS/ERS) criteria after administering 400 μg salbutamol by AccuhalerTM. Impulse oscillometry measurements (resistance at 5 Hz [R5], resistance at 20 Hz [R20], reactance at 5 Hz [X5]) and spirometry (forced expiratory volume in 1 second [FEV(1)], forced vital capacity [FVC], forced expiratory flow from 25% to 75% of vital capacity [FEF(25-75)]) were recorded pre and postbronchodilator. Ninety-five asthmatic and 61 healthy subjects underwent screening. Mean percent (standard error of the mean [SEM]) baseline prebronchodilator FEV(1) was 83.99 (2.23) for patients with asthma, and 99.25 (1.72) for healthy subjects. Baseline percent predicted IOS indices in the group with asthma were 162.22 (7.5) for R5; 154.73 (4.71) for R20; and 441.72 (173.86) for X5. In healthy volunteers, corresponding values were 111.01 (3.96), 127.75 (4.12), and -229.80 (125.75). R5 was the only IOS measure that showed correlation with spirometry (FEV(1)) in both groups. The mean percent (SEM) predicted postbronchodilator change in FEV(1) and R5 in patients with asthma was 6.35 (0.65) and -33.78 (4.43); correspondingly in healthy subjects it was 2.24 (0.32) and -14.91 (2.48). A negative correlation was demonstrated (r = -0.40, P < .001 between the 2 indices in patients with asthma. Linear regression modeling demonstrated that 1 unit change in %FEV(1) corresponds to a 2.5% change in %R5. Low-frequency IOS as R5 and spirometry as FEV(1) correlate in patients with asthma and healthy subjects, with changes that can be predicted by linear regression.

Nair A ，Ward J ，Lipworth BJ 《-》

Small airway dysfunction by impulse oscillometry in asthmatic patients with normal forced expiratory volume in the 1st second values.

Pisi R ，Tzani P ，Aiello M ，Martinelli E ，Marangio E ，Nicolini G ，Olivieri D ，Chetta A ... -  《-》

Detection of the airway obstruction stage in asthma using impulse oscillometry system.

Qi GS ，Zhou ZC ，Gu WC ，Xi F ，Wu H ，Yang WL ，Liu JM ... -  《-》

Are we overlooking persistent small airways dysfunction in community-managed asthma?

Whether small airways dysfunction persists in patients with asthma receiving standard community treatment is unknown. Impulse oscillometry (IOS) is a sensitive measure of small airways function. To assess the degree of small airways dysfunction in a cross-section of patients with community-managed asthma. We analyzed primary care referral data from patients with persistent asthma (n = 378) receiving standard community therapy, screened using spirometry and IOS. We compared patients by British Thoracic Society asthma treatment step (2-4). Step 2 patients were not different from step 3 patients receiving long-acting beta-agonist (LABA). Step 4 patients differed from step 2 by: higher inhaled corticosteroid (ICS) dose (P < .0001); lower forced expiratory volume in 1 second (FEV(1)%; P = .02) and forced mid-expiratory flow (FEF(25-75%); P = .001); higher frequency of resonance (F(res); P = .02) and peripheral airway resistance (R5-R20; P = .006); whereas for steps 3 vs 4 there were differences in F(res) (P < .05) and R5-R20 (P = .006). There were high proportions of abnormality for R5-R20 (>0.03 kPa/L/s) at steps 2, 3, and 4, respectively: 64.6%, 63.5%, and 69.9%. Step 2 patients receiving extra-fine particle ICS demonstrated lower total airway resistance at 5Hz (R5) vs patients receiving standard ICS (124.1% vs 138.3%, P < .05), with no difference in FEV(1). At step 4, R5 remained elevated at 141.3% despite concomitant LABA, with only 2.4% using extra-fine ICS. Persistent small airways dysfunction occurs despite treatment at steps 2 through 4 of current asthma guidelines. Extra-fine ICS may reduce airway resistance at step 2. Prospective studies with extra-fine ICS ± LABA at steps 2 through 4 are required to discern whether improving small airways function might result in long-term improved control.

Anderson WJ ，Zajda E ，Lipworth BJ 《-》

Impulse oscillometry in COPD: identification of measurements related to airway obstruction, airway conductance and lung volumes.

Kolsum U ，Borrill Z ，Roy K ，Starkey C ，Vestbo J ，Houghton C ，Singh D ... -  《-》