Computational fluid dynamics can detect changes in airway resistance in asthmatics after acute bronchodilation

• Published in: Journal of biomechanics 2008-01, Vol.41 (1), p.106-113
• Main Authors: De Backer, J.W, Vos, W.G, Devolder, A, Verhulst, S.L, Germonpré, P, Wuyts, F.L, Parizel, P.M, De Backer, W
• Format: Article
• Language: English
• Subjects: Adrenergic beta-Agonists - pharmacology; Adrenergic beta-Agonists - therapeutic use; Adult; Airway Resistance - drug effects; Airway Resistance - physiology; Amphetamines - pharmacology; Amphetamines - therapeutic use; Asthma; Asthma - drug therapy; Asthma - physiopathology; Bronchi - drug effects; Bronchi - pathology; Bronchi - physiopathology; Bronchodilation; Bronchodilator Agents - pharmacology; Bronchodilator Agents - therapeutic use; Computational Biology - methods; Computational fluid dynamics (CFD); Computer Simulation; Female; Forced Expiratory Volume - drug effects; Functional imaging; Geometry; Humans; Hydroxyquinolines - pharmacology; Hydroxyquinolines - therapeutic use; Lungs; Male; Measurement techniques; Medical imaging; Middle Aged; Models, Biological; Physical Medicine and Rehabilitation; Quinolones - pharmacology; Quinolones - therapeutic use; Respiratory Function Tests - methods; Respiratory system; Rheology; Spirometry; Tomography, X-Ray Computed - methods; Total Lung Capacity - drug effects; Vital Capacity - drug effects
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/j.jbiomech.2007.07.009

Abstract The effect of a bronchodilator in asthmatics is only partially described by changes in spirometric values since no information on regional differences can be obtained. Imaging techniques like high-resolution computed tomography (HRCT) provide further information but lack detailed information on specific airway responses. The aim of the present study was to improve the actual imaging techniques by subsequent analysis of the imaging data using computational fluid dynamics (CFD). We studied 14 mild to moderately severe asthmatics. Ten patients underwent HRCT before and 4 h after inhalation of a novel long acting β2 agonist (LABA) that acts shortly after inhalation. Four patients were studied for chronic effects and underwent CT scans twice after adequate wash-out of bronchodilators. In the active group, a significant bronchodilator response was seen with a forced expiratory volume in 1 s (FEV1) increase of 8.78±−6.27%pred vs −3.38±6.87%pred in the control group. The changes in FEV1 correlated significantly with the changes in distal airway volume ( r =0.69, p =0.007), total airway resistance ( r =−0.73, p =0.003) and distal airway resistance ( r =−0.76, p =0.002) as calculated with the CFD method. The changes in distal Raw were not fully homogeneous. In some patients with normal FEV1 at baseline, CFD-based changes in Raw were still detectable. We conclude that CFD calculations, based on airway geometries of asthmatic patients, provide additional information about changes in regional Raw . All changes in the CFD-based calculated Raw significantly correlate with the observed changes in spirometric values therefore validating the CFD method for the studied application.