Effects of homogeneous and heterogeneous changes in the lung periphery on spirometry results

Estimation of Lung Properties From the Forced Expiration Data

“…In this study, however, the synthetic data were corrupted by realistic white noise, which allowed to assess its impact on estimate variances (random errors), as well as to compare this effect with the bias resulting from regularization (systematic errors). Nevertheless, it is planned to use spirometry data of another origin in the future, including spirometric curves generated by the computational model with heterogeneous bronchial tree [38].…”

Quantitative Assessment of the Airway Response to Bronchial Tests Based on a Spirometric Curve Shift

“…including the asymmetrical bronchial tree (Fig. 3)the AsymM [24]. All the synthetic data were finally disturbed by additive white noise (SD = 0.01 L/s).…”

“…As such, they are not suitable to properly capture distributed phenomena in flexible airways, crucial for the forced expiration process. Despite these difficulties, the computational model for forced expiration has been proposed and widely recognized [21], and then successfully further developed [22]- [24].…”

“…The novelty of this approach covers three main issues: the principle of differential measurement (suppressing the influence of uncertain model parameters) applied to assess the degree, site and width of response, as well as the relative changes in airway generation resistances and compliances, a new mathematical model for the modification of airway mechanics caused by a bronchial test, as well as using both synthetic and clinical data to evaluate the method. The synthetic data used for validating the method were generated by the inverse model [29], and, to avoid the inverse crime [31], by the computational models for forced expiration with full degrees of freedom: including the symmetrical [22] and asymmetrical bronchial tree [24]. Finally, the potential clinical application of this approach was illustrated using spirometry results from bronchodilation tests of three asthmatic patients.…”

Moving closer to clinical application of the forced oscillation technique in asthma monitoring?

“…One challenge posed by the use of physiological monitoring in asthma is the relative lack of sensitivity of spirometry (and derived peak expiratory flow) to disease causing heterogeneity of ventilation in the smaller airways of the lung, 4 which are a major site of asthmatic airway inflammation 5,6 and airway hyper‐responsiveness 7 . In addition, the relatively limited dynamic range of variation in spirometry measurements over time, particularly in the presence of incompletely reversible airflow obstruction, may preclude its use as an effective monitoring tool 8 …”