The conventional pulmonary function tests are based on spirometry, which unfortunately doesn't produce accurate and reproducible results if performed without the supervision of specially trained staff. We recently showed that forced oscillation technique is best suited for the homemonitoring of respiratory patients. The aim of this study was to develop a real-time data processing algorithm for the automatic unsupervised assessment of the lung obstruction, a network architecture for the data transmission and a webbased application for the storage and management of the data. The results demonstrated a high reliability of the algorithm, the robustness of the data communication protocols and the effectiveness of the data management web portal. In conclusion, our system allows a reliable automatic home monitoring of lung obstruction and it may improve the efficacy and efficiency of the management of respiratory patients through an improved tailoring of the clinical treatments and an early detection of exacerbations.

SummaryIntroduction: This article is part of the Focus Theme of Methods of Information in Medicine on “Biosignal Interpretation: Advanced Methods for Neural Signals and Images”.Objectives: This paper presents the main concepts of a decision making approach for the remote management of COPD patients based on the early detection of disease exacerbation episodes.Methods: An e-diary card is defined to evaluate a number of physiological variables and clinical parameters acquired remotely by means of wearable and environmental sensors deployed in patients’ long-stay settings. The automatic evaluation of the card results in a so-called Chronic Status Index (CSI) whose computation is tailored to patients’ specific manifestation of the disease (i.e., patient’s phenotype). The decision support method relies on a parameterized analysis of CSI variations so as to early detect worsening changes, identify exacerbation severity and track the patterns of recovery.Results: A preliminary study, carried out in real settings with 30 COPD patients monitored at home, has shown the validity and sensitivity of the method proposed, which was effectively able to timely and correctly identify patients’ critical situation.Conclusion: The preliminary results showed that the proposed e-diary card, which presents several novel features with respect to other solutions presented in the literature, can be practically used to remotely monitor COPD patients.

The effects of full lung inflation on respiratory conductance (Grs) and reactance (Xrs) were measured in 15 subjects with moderate to severe chronic obstructive pulmonary disease (COPD) and 11 matched healthy control subjects. Airway distensibility was estimated from the ratio of the difference of Grs between functional residual capacity and total lung capacity to the relevant changes in lung volume (ΔGrs/ΔVl) or transpulmonary pressure (ΔGrs/ΔPtp). Similar analysis was applied to Xrs to estimate lung volume recruitment (ΔXrs/ΔVl or ΔXrs/ΔPtp). The extent of emphysema in COPD subjects was estimated from the percentage of low attenuation area (LAA) at high-resolution computed tomography. At baseline, ΔGrs/ΔVl and ΔXrs/ΔVl were significantly less in COPD than control subjects, indicating less distensibility and volume recruitment in the former. In COPD, ΔGrs/ΔPtp and ΔXrs/ΔPtp were uncorrelated with LAA but correlated with 1-s forced expiratory volume and with each other. After albuterol, both ΔGrs/ΔPtp and ΔGrs/ΔVl became significantly and negatively correlated with LAA, while ΔXrs/ΔPtp and ΔXrs/ΔVl decreased significantly independently of LAA. Moreover, ΔGrs/ΔPtp and ΔXrs/ΔPtp with lung inflation were no longer correlated with each other, suggesting that airway distensibility and volume recruitment were affected differently by airway smooth muscle tone. Assuming that Grs mainly reflects airway caliber and Xrs the number of ventilated lung units, we conclude that airway smooth muscle contributes to airway stiffness and ventilation inhomogeneities in COPD subjects with prevailing bronchitis but only to the latter in those with more emphysema. We suggest that changes of airway distensibility and volume recruitment with a bronchodilator may be useful for disease phenotyping.

No abstract

No abstract