Rationale: Respiratory resistance (Rrs) and reactance (Xrs) as measured by oscillometry and their intrabreath changes have emerged as sensitive parameters for detecting early pathological impairments during tidal breathing. Objectives: This study evaluates the prevalence and association of abnormal oscillometry parameters with respiratory symptoms and respiratory diseases in a general adult population. Methods: A total of 7,560 subjects in the Austrian LEAD (Lung, hEart, sociAl, boDy) Study with oscillometry measurements (computed with the Resmon Pro FULL; Restech Srl) were included in this study. The presence of respiratory symptoms and doctor-diagnosed respiratory diseases was assessed using an interview-based questionnaire. Rrs and Xrs at 5 Hz, their inspiratory and expiratory components, the area above the Xrs curve, and the presence of tidal expiratory flow limitation were analyzed. Normality ranges for oscillometry parameters were defined. Measurements and Main Results: The overall prevalence of abnormal oscillometry parameters was 20%. The incidence of abnormal oscillometry increased in the presence of symptoms or diagnoses: 17% (16–18%) versus 27% (25–29%), P < 0.0001. All abnormal oscillometry parameters except Rrs at 5 Hz were significantly associated with respiratory symptoms/diseases. Significant associations were found, even in subjects with normal spirometry, with abnormal oscillometry incidence rates increasing by 6% (4–8%; P < 0.0001) in subjects with symptoms or diagnoses. Conclusions: Abnormal oscillometry parameters are present in one-fifth of this adult population and are significantly associated with respiratory symptoms and disease. Our findings underscore the potential of oscillometry as a tool for detecting and evaluating respiratory impairments, even in individuals with normal spirometry.

Background: Telemonitoring trials for early detection of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) have provided mixed results. Day-to-day variations in lung function measured by the forced oscillation technique (FOT) may yield greater insight. We evaluated the clinical utility of home telemonitoring of variability in FOT measures in terms of 1) the relationship with symptoms and quality of life (QoL); and 2) the timing of variability of FOT measures and symptom changes prior to AECOPD.Methods: Daily FOT parameters at 5 Hz (resistance (R) and reactance (X); Resmon Pro Diary, Restech Srl, Milan, Italy), daily symptoms (COPD Assessment Test (CAT)) and 4-weekly QoL data (St George's Respiratory Questionnaire (SGRQ)) were recorded over 8–9 months from chronic obstructive pulmonary disease (COPD) patients. Variability of R and X was calculated as the standard deviation (sd) over 7-day running windows and we also examined the effect of varying window size. The relationship of FOTversusCAT and SGRQ was assessed using linear mixed modelling, daily changes in FOT variability and CAT prior to AECOPD using one-way repeated measures ANOVA.Results: Fifteen participants with a mean±sdage of 69±10 years and a % predicted forced expiratory volume in 1 s (FEV₁) of 39±10% had a median (interquartile range (IQR)) adherence of 95.4% (79.0–98.8%). Variability of the inspiratory component of X (indicated by the standard deviation of inspiratory reactance (SDX_insp)) related to CAT and weakly to SGRQ (fixed effect estimates 1.57, 95% CI 0.65–2.49 (p=0.001) and 4.41, 95% CI −0.06 to 8.89 (p=0.05), respectively). SDX_inspchanged significantly on the same day as CAT (1 day before AECOPD, both p=0.02) and earlier when using shorter running windows (3 days before AECOPD, p=0.01; accuracy=0.72 for 5-day windows).Conclusions: SDX_inspfrom FOT telemonitoring reflects COPD symptoms and may be a sensitive biomarker for early detection of AECOPD.

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 home-monitoring 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 web-based 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.

Recent documents from leading international pediatric respiratory societies have strongly encouraged the use of lung function tests in clinical practice and research. These tests can explore ventilatory function across its volumetric and temporal domains, providing information on the intrapulmonary location and extent of damage caused by respiratory diseases. The choice of which test to use in each case to investigate presenting respiratory symptoms depends on the patient’s symptoms and the diagnostic–therapeutic phase being addresse d. In the most common and representative chronic pediatric condition—bronchial asthma—lung function tests play an especially important role due to the disease’s complexity and the fluctuating nature of airway obstruction. This review aims to examine the potential of various lung function tests in asthma, helping clinicians and researchers to optimize diagnosis and follow-up with the most appropriate methodology. While spirometry and flow resistance measurements using the interrupter technique have historically been the cornerstones of diagnosis and clinical monitoring in childhood asthma, the advent of new technologies—such as multiple breath nitrogen washout (MBNW) and the forced oscillation technique (FOT)—is opening up the door to a more nuanced view of the disease. These tools allow for an evaluation of asthma as a structurally complex and topographically and temporally disorganized condition. FOT, in particular, facilitates measurement acceptability in less cooperative subjects, both in respiratory physiology labs and even at the patient’s home.