Analysis of Forced Wheezes in Asthma Patients

Abstract

Background: Spirometric parameters can be normal in many stable asthma patients, making a diagnosis difficult at certain times in the course of disease. Objectives: The present study aims to find differences and similarities in the acoustic characteristics of forced wheezes among asthma patients with and without normal spirometric values. Methods: Eleven chronic asthma patients (8 men/3 women) with moderate-to-severe airway obstruction (FEV₁ 48.4%), 9 stable asthma patients (6 males/3females) with normal spirometry (FEV₁ 84.0%) and a positive methacholine test and 14 healthy subjects (8/6) were enrolled in the study. A contact sensor was placed on the trachea, and wheezes were detected by a modified Shabtai-Musih algorithm in a time-frequency representation. Results: More wheezes were recorded in obstructive asthma patients than in stable asthma and control subjects: nonstable asthma 13.6 (13.3), stable asthma 3.5 (3.0) and control subjects 2.5 (2.1). The mean frequency of all wheezes detected was higher in control subjects than in either stable or non-stable asthma patients. The change in the total number of wheezes after terbutaline inhalation was more pronounced in nonstable asthma patients than in stable asthmatics and control subjects. Conclusions: This study confirms that wheeze recording during forced expiratory maneuvers can be a complementary measure to spirometry to identify asthma patients.

Computerized Adventitious Respiratory Sounds as Outcome Measures for Respiratory Therapy: A Systematic Review

“…The majority of the included studies were quasi-experimental, 5,[20][21][22][23][24][25] 3 studies were observational, [26][27][28] and 2 studies were randomized controlled trials (Table 2). 29,30 Ten studies recruited patients receiving specialized care, and 2 studies recruited patients during hospital admission.…”

“…Eight studies were conducted with adults (n ϭ 167; 60.7%; age range 21-73 years) 5,21,24-29 and 4 with children (n ϭ 108 [39.3%]; age range 4 months-18 y). 20,22,23,30 The interventions in most studies consisted of pharmacotherapy [20][21][22][23][24][25][26][27][28][29][30] ; only 2 studies combined pharmacotherapy with respiratory physical therapy. 5,29 The respiratory physical therapy consisted mainly of an active cycle of breathing techniques, 5,29 but also breathing retraining techniques (incentive spirometry, thoracic mobility, expansion and flexibility exercises, and aerobic training).…”

“…29 In almost all studies, the respiratory sounds were recorded in more than one chest location; however, in 3 studies recordings were performed exclusively in the trachea. 21,25,26 Only the 3…”

“…The recording devices used varied among studies, as follows: microphones 21,24,25,27,29 ; piezoelectric sensors 20,22,23,26,30 ; and electronic stethoscopes. 5,28 Algorithms based on fast Fourier transformation were the most used to automatically detect ARSs.…”

“…5,28 Algorithms based on fast Fourier transformation were the most used to automatically detect ARSs. Two studies 28,29 used an algorithm based on short-time Fourier transformation, and one study 25 used a modification of the algorithm proposed by Shabtai-Musih et al 31 and HomsCorbera et al 32 A total of 9 studies analyzed WHs (3 studies were conducted in children), 2 studies analyzed CRs, 5,27 and one study analyzed both WHs and CRs in children. 30 Two studies detected breathing cycles automatically; one study 5 used an analogous method reported by Qiu et al, 33 and the other study 30 used the algorithm of Huq and Moussavi.…”