A new tidal breathing measurement device detects bronchial obstruction during methacholine challenge test.

PURPOSE: Bronchial hyperresponsiveness (BHR), a hallmark of bronchial asthma, is typically diagnosed through a methacholine inhalation test followed by spirometry, known as the methacholine challenge test (MCT). While spirometry relies on proper patients' cooperation and precise execution of forced breathing maneuvers, we conducted a comparative analysis with the portable nanomaterial-based sensing device, SenseGuard™, to non-intrusively assess tidal breathing parameters. MATERIALS AND METHODS: In this prospective study, 37 adult participants with suspected asthma underwent sequential spirometry and SenseGuard™ measurements after inhaling increasing methacholine doses. RESULTS: Among the 37 participants, 18 were MCT responders, 17 were non-responders and 2 were excluded due to uninterpretable data. The MCT responders exhibited a significant lung function difference when comparing the change from baseline to maximum response. This was evident through a notable decrease in forced expiratory volume in 1 â€‹s (FEV1) levels in spirometry, as well as in prominent changes in tidal breathing parameters as assessed by SenseGuard™, including the expiratory pause time (Trest) to total breath time (Ttot) ratio, and the expiratory time (Tex) to Ttot ratio. Notably, the ratios Trest/Ttot (∗p â€‹= â€‹0.02), Tex/Ttot (∗p â€‹= â€‹0.002), and inspiratory time (Tin) to Tex (∗p â€‹= â€‹0.04) identified MCT responders distinctly, corresponding to spirometry (∗p â€‹< â€‹0.0001). CONCLUSIONS: This study demonstrates that tidal breathing assessment using SenseGuard™ device reliably detects clinically relevant changes of respiratory parameter during the MCT. It effectively distinguishes between responders and non-responders, with strong agreement to conventional spirometry-measured FEV1. This technology holds promise for monitoring clinical respiratory changes in bronchial asthma patients pending further studies.

Changes in tidal breathing biomarkers as indicators of treatment response in AECOPD patients in an acute care setting.

PURPOSE: Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is a complication of COPD that typically necessitates intensified treatment and hospitalization. It is linked to higher morbidity, mortality and healthcare spending. Assessment of therapy response for AECOPD is difficult due to the variability of symptoms and limitations in current measures. Hence, there is a need for new biomarkers to aid in the management of AECOPD in acute care settings. MATERIALS AND METHODS: Fifteen hospitalized AECOPD patients (GOLD 3-4) were enrolled in this study. Treatment response was assessed daily through clinical evaluations and by monitoring tidal breathing biomarkers (respiratory rate [RR], expiratory time [Tex], inspiratory time [Tin], expiratory pause [Trst], total breath time [Ttot]), using a novel, wearable nanosensor-based device (SenseGuard™). RESULTS: Patients who showed significant clinical improvement had substantial changes in ΔTex/Ttot (+14%), ΔTrst/Ttot (-18%), and ΔTin/Tex (+0.09), whereas patients who showed mild or no clinical improvement had smaller changes (+5%, +3%, and -0.03, respectively). Linear regression between change in physician's assessment score and the median change in tidal breathing parameters was significant for Tin/Tex (R2 â€‹= â€‹0.449, ∗p â€‹= â€‹0.017), Tex/Ttot (R2 â€‹= â€‹0.556, ∗p â€‹= â€‹0.005) and Trst/Ttot (R2 â€‹= â€‹0.446, ∗p â€‹= â€‹0.018), while no significant regression was observed for RR, Tin/(Trst â€‹+ â€‹Tex) and Tin/Ttot. CONCLUSIONS: Our study demonstrates the potential of the SenseGuard™ to monitor treatment response in AECOPD patients by measuring changes in tidal breathing biomarkers, which were shown to be associated with significant changes in the patients' respiratory condition as evaluated by physicians. However, further large-scale clinical studies are needed to confirm these findings.

Sensor Arrays Based on Polycyclic Aromatic Hydrocarbons: Chemiresistors versus Quartz-Crystal Microbalance.

Arrays of broadly cross-reactive sensors are key elements of smart, self-training sensing systems. Chemically sensitive resistors and quartz-crystal microbalance (QCM) sensors are attractive for sensing applications that involve detection and classification of volatile organic compounds (VOCs) in the gas phase. Polycyclic aromatic hydrocarbon (PAH) derivatives as sensing materials can provide good sensitivity and robust selectivity towards different polar and nonpolar VOCs, while being quite tolerant to large humidity variations. Here, we present a comparative study of chemiresistor and QCM arrays based on a set of custom-designed PAH derivatives having either purely nonpolar coronas or alternating nonpolar and strongly polar side chain termination. The arrays were exposed to various concentrations of representative polar and nonpolar VOCs under extremely varying humidity conditions (5-80% RH). The sensor arrays' classification ability of VOC polarity, chemical class and compound separation was explained in terms of the sensing characteristics of the constituent sensors and their interaction with the VOCs. The results presented here contribute to the development of novel versatile and cost-effective real-world VOC sensing platforms.

Polycyclic aromatic hydrocarbon for the detection of nonpolar analytes under counteracting humidity conditions.

Real-world samples contain reducing and oxidizing chemical agents as well as large and small (bio)molecules, which are polar or nonpolar in nature. Sensing nonpolar analytes, which is of paramount importance for a wide variety of applications, is generally more difficult to achieve than sensing polar analytes. Here, we report on empirical observations of a unique polycyclic aromatic hydrocarbon derivative, referred as PAH-A, whose structure has a triangular-shaped aromatic core (with a carbon number of 60) and contains hydrophobic mesogens terminated with hydrophobic alkyl chains. We show that films made of PAH-A enable excellent sensitivity to nonpolar analytes, compared to polar analytes, in a setting of 5-40% counteracting relative humidity. This finding is based on monitoring the changes in the physical/optical properties of thin PAH-A films upon exposure to nonpolar and polar analytes, by means of quartz crystal microbalance and spectroscopic ellipsometry measurements. A comparison with other polycyclic aromatic hydrocarbon derivatives with different cores or organic functionalities is provided and discussed.