The Evaluation of the Fractal Variability of Breathing Pattern in Asthmatic Patients

There is no study about fractal variability of breathing pattern in patients with respiratory diseases, such as asthma. The aim of this study was evaluating fractal variability of breathing pattern in healthy and asthmatic cases. Forty men, including 10 healthy volunteers, 10 patients with controlled atopic asthma (CAA), 10 patients with uncontrolled atopic asthma (UAA), and 10 patients with uncontrolled non-atopic asthma (UNAA) referred to the outpatient clinic of Dr. Masih Daneshvari Hospital (Tehran, Iran) were enrolled in this study. The thoraco-abdominal movements were collected using two respiratory belts and then signals were calibrated to respiratory volume. We analyzed the fractal variability of inter breath interval (IBI) and volume fluctuation using detrended fluctuation analysis (DFA). The α index values in healthy, CAA, UAA, and UNAA cases with respect to IBI were 0.82±0.03, 0.73±0.06, 0.68±0.04, and 0.57±0.04, respectively, and with respect to volume fluctuation were 0.83±0.10, 0.75±0.06, 0.70±0.05, and 0.59±0.04, respectively. There were significant differences between all groups in α index values of both IBI and volume fluctuation (p<0.05). We concluded that the fractal correlation of breathing pattern in asthmatic patients is lower than healthy cases. This difference increased in uncontrolled asthma.