Prediction of Individual Dynamic Thermal Sensation in Subway Commute Using Smart Face Mask.

Wearable sensors and machine learning algorithms are widely used for predicting an individual's thermal sensation. However, most of the studies are limited to controlled laboratory experiments with inconvenient wearable sensors without considering the dynamic behavior of ambient conditions. In this study, we focused on predicting individual dynamic thermal sensation based on physiological and psychological data. We designed a smart face mask that can measure skin temperature (SKT) and exhaled breath temperature (EBT) and is powered by a rechargeable battery. Real-time human experiments were performed in a subway cabin with twenty male students under natural conditions. The data were collected using a smartphone application, and we created features using the wavelet decomposition technique. The bagged tree algorithm was selected to train the individual model, which showed an overall accuracy and f-1 score of 98.14% and 96.33%, respectively. An individual's thermal sensation was significantly correlated with SKT, EBT, and associated features.

Short- and medium-term effect of inhaled corticosteroids on exhaled breath biomarkers in severe asthma.

Inhaled corticosteroids (ICS) are the mainstay of therapy in asthma, but benefits vary due to disease heterogeneity. Steroid insensitivity is a particular problem in severe asthma, where patients may require systemic corticosteroids and/or biologics. Biomarkers sensitive to ICS over a short period of time could inform earlier and more personalised treatment choices. To investigate how exhaled breath biomarkers change over two-hours and one-week following monitored ICS dosing in severe asthma patients with evidence of uncontrolled airway inflammation. Patients with severe asthma and elevated fractional exhaled nitric oxide (FeNO) (⩾45 ppb, indicative of active airway inflammation) were recruited. Exhaled breath biomarkers were evaluated using (FeNO), exhaled breath temperature (EBT), particles in exhaled air (PExA) and volatile organic compounds (VOCs). Samples were collected over 2 h following observed inhalation of 1000 mcg fluticasone propionate, and at a second visit 1 week after taking the same dose daily via an inhaler monitoring device that recorded correct actuation and inhalation. Changes in parameters over 2 h were analysed by the Friedman test and 1 week by Wilcoxon's test (p-value for significance set at 0.05; for VOCs false discovery rateqof 0.1 by Benjamini-Hochberg method applied). 17 participants (9 male) were recruited, but three could not complete PExA and two FeNO testing, as they were unable to comply with the necessary technique; complete datasets were available from 12 (9 male) with median (interquartile range) age 45 (36-59) yrs. EBT (p< 0.05) and levels of six VOCs (q< 0.1) fell over the 2 h after high dose ICS; there were no changes in FeNO or PExA. After one week of using high dose ICS, there were falls in FeNO, EBT and two VOCs (p< 0.05), but no changes in PExA. Reduction in EBT over the short and medium term after high dose ICS may reflect airway vascular changes, and this, together with the observed changes in exhaled VOCs, merits further investigation as potential markers of ICS use and effectiveness.

Medical devices in allergy practice.

Medical devices provide people with some health benefits in terms of diagnosis, prevention, treatment, and monitoring of disease processes. Different medical specialties use varieties of medical devices more or less specific for them. Allergology is an interdisciplinary field of medical science and teaches that allergic reactions are of systemic nature but can express themselves at the level of different organs across the life cycle of an individual. Subsequently, medical devices used in allergology could be regarded as: 1) general, servicing the integral diagnostic and management principles and features of allergology, and 2) organ specific, which are shared by organ specific disciplines like pulmonology, otorhinolaryngology, dermatology, and others. The present position paper of the World Allergy Organization (WAO) is meant to be the first integral document providing structured information on medical devices in allergology used in daily routine but also needed for sophisticated diagnostic purposes and modern disease management. It is supposed to contribute to the transformation of the health care system into integrated care pathways for interrelated comorbidities.

Fractional exhaled breath temperature in patients with asthma, chronic obstructive pulmonary disease, or systemic sclerosis compared to healthy controls.

Exhaled breath temperature has been suggested to reflect airway inflammation, and it would be plausible to measure the peripheral airway temperature as a correlate to peripheral airway inflammation. This study aims to explore the relative peripheral airway temperature in patients with asthma, chronic obstructive pulmonary disease (COPD) or systemic sclerosis (SSc) compared to healthy controls, and relate to lung function and exhaled nitric oxide. Sixty-five subjects (16 asthmatics, 18 COPD patients, 17 SSc patients and 14 healthy subjects) performed fractional exhaled breath temperature measurements using a novel device, fractional exhaled NO measurements, spirometry, impulse oscillometry, body plethysmography and CO-diffusion capacity test. A significant overall difference among all the patient groups was seen in both the Tmax (= peak values of the entire exhalation) and T3max (= peak value of the last fraction of the exhaled volume). A significant difference in T3/T1 ratio (= the ratio of peripheral versus central air temperature) was found between asthmatic subjects and those with COPD or SSc. In addition, T1max (= temperature in the central), T3max (= peripheral airways) and the T3/T1ratio related to several volumetric measurements (both in absolute values and as percent predicted), such as vital capacity, total lung capacity, forced expiratory volume in 1 s, and diffusion capacity. The temperature ratio of the peripheral versus central airways was lower in patients with COPD or SSc compared to asthmatics, who in turn presented similar levels as the controls. There was also a large overlap between the groups. Overall, the airway temperatures were related to absolute lung volumes, and specifically, the peripheral temperature was related to the gas diffusion capacity (% predicted), suggesting a link to the vascular component.

Exhaled breath temperature as a tool for monitoring asthma control after an attack in children.

BACKGROUND: Exhaled breath temperature (EBT) has been suggested as a non-invasive marker of airway inflammation in asthma. There have been no studies examining longitudinal changes in EBT following asthma attacks. OBJECTIVE: To investigate changes in EBT during and after an asthma attack and to relate these changes to changes in respiratory physiological measurements. METHODS: We evaluated 38 hospitalized children aged 5-18 years diagnosed with an asthma attack. Spirometry was performed upon hospitalization. During hospitalization, EBT, peak expiratory flow rate (PEFR), and asthma score were measured daily. These tests were repeated 1 week and 1 month after discharge. The overall PEFR change, temporal changes in plateau values at the end of expiration, and time-dynamic associations were evaluated using linear mixed models. RESULTS: FEV1 was lower at admission than at discharge (63.3 ± 24 vs 99.5 ± 14 percent of predicted, P < 0.001). The EBT was higher at admission than at 1 week after discharge (34.1°C [range: 33.9-34.8°C] vs 33.6°C [range: 33.0-34.2°C], P = 0.007); overall, EBTs decreased over time (P = 0.007). Among individual subjects, decreased EBT was correlated with increased PEFR over time. Furthermore, plateau values at the end of expiration had a time-dependent, dynamic association with the PEFR during hospitalization (P = 0.005) and between asthma attack onset and asthma status stabilization (P = 0.032). CONCLUSIONS: The EBT was elevated during asthma attacks and gradually decreased until asthma was well controlled. The EBT may be a useful, non-invasive tool for monitoring asthma control in children.

In-mask temperature and humidity can validate respirator wear-time and indicate lung health status.

The effectiveness of respiratory protection is dependent on many factors, including the duration and times during the day when it is worn. To date, these factors could only be assessed by direct observation of the respirator user. We describe the novel use of a data-logging temperature and humidity sensor (iButton Hygrochron) located inside a facemask to quantify respirator wear-time through supervised experiments (Phase 1) and an unsupervised wearing trial (Phase 2). Additionally, in Phase 1 the in-mask temperature was compared with measurements of exhaled breath temperature. We found humidity responds more rapidly than temperature to donning a mask, so it was considered a more sensitive measure of wear-time, particularly for short durations. Supervised tests showed that this method can provide accurate and precise estimates of wear-time, although the approach may be unsuitable for use in situations where there is high ambient humidity. In-mask temperature is closely associated with exhaled breath temperature, which is linked to lung inflammation. This technique could provide a useful way of evaluating the effectiveness of respirators in protecting health in real-life situations.

Validation of the Exhaled Breath Temperature Measure: Reference Values in Healthy Subjects.

BACKGROUND: Exhaled breath temperature (EBT) is a new noninvasive method for the study of inflammatory respiratory diseases with a potential to reach clinical practice. However, few studies are available regarding the validation of this method, and they were mainly derived from small, pediatric populations; thus, the range of normal values is not well established. The aim of this study was to measure EBT values in an Italian population of 298 subjects (mean age, 45.2 ± 15.5 years; 143 male subjects; FEV1, 97.2% ± 5.8%; FVC, 98.4% ± 3.9%) selected from 867 adult volunteers to define reference values in healthy subjects and to analyze the influence of individual and external variables on this parameter. METHODS: EBT was measured with an X-halo PRO device to different ambient temperature ranging from 0°C to 38°C. RESULTS: We report reference values of EBT in healthy white subjects who had never smoked. EBT values were strongly influenced by the external temperature and to a lesser extent according to sex. CONCLUSIONS: In a large population of healthy subjects who never smoked, these data provide reference values for measuring EBT as a basis for future studies. Our results are contribute to the promotion of EBT from "bench" to "bedside."

Clinical implication of exhaled breath temperature measurement in pediatric asthma

PURPOSE: Exhaled breath temperature (EBT) has been suggested as a noninvasive marker of airway inflammation in asthma. The aim of this study was to determine its clinical implication in children with asthma. METHODS: A total of 233 children were enrolled in this study. Among them, 116 were asthmatic children and 117 were healthy children. Spirometry, bronchodilator response (BDR) test, methacholine challenge test, and skin prick test were performed. EBT, fractional exhaled nitric oxide (FeNO), blood eosinophils, and total IgE levels were measured. EBT was measured by using X-halo. RESULTS: EBT was significantly higher in the asthma group than in the control group (median [interquartile range], 32.1℃ [30.0℃–33.9℃] vs. 29.7℃ [29.0℃–31.3℃], P<0.001). EBT was significantly higher in poorly or partly controlled asthmatic children than well-controlled asthmatic children (33.5℃ [31.0℃–34.4℃] vs. 30.3℃ [29.3℃–32.9℃], P<0.0001). Among total subjects, EBT was significantly higher in the atopic group than in the nonatopic group (32.4℃ [30.3℃–34.0℃] vs. 29.8℃ [29.0℃–30.3℃], P<0.001). There were neither significant associations between EBT and BDR (r=0.109, P=0.241) nor between EBT and PC20 (provocation concentration causing a 20% fall in FEV1) in total subjects (r=0.127, P=0.316). EBT did not show any association with FeNO (r=0.353, P=0.071). CONCLUSION: Our study suggests that EBT might play a role as an ancillary marker for allergic airway inflammation and the degree of control in pediatric asthma patients. Additional studies are required to explore the value of EBT in detail.

Exhaled Breath Temperature as a Novel Marker of Future Development of COPD: Results of a Follow-Up Study in Smokers.

Although only less than one-third of smokers develop COPD, early marker(s) of COPD development are lacking. The aim of this research was to assess the ability of an average equilibrium exhaled breath temperature (EBT) in identifying susceptibility to cigarette smoke so as to predict COPD development in smokers at risk. The study was a part of a multicenter prospective cohort study in current smokers (N = 140, both sexes, 40-65 years, ≥20 pack-years) with no prior diagnosis of COPD. Diagnostic workup includes history, physical, quality of life, hematology and highly sensitive CRP, EBT before and after smoking a cigarette, lung function with bronchodilator test, and 6-minute walk test. Patients without a diagnosis of COPD and in GOLD 1 stage at initial assessment were reassessed after 2 years. COPD was additionally diagnosed based on lower level of normal (LLN) lung function criteria. Utility of EBT for disease progression was analyzed using receiver operator curve (ROC) and logistic regression analyses. Change in EBT after smoking a cigarette at initial visit (ΔEBT) was significantly predictive for disease progression (newly diagnosed COPD; newly diagnosed COPD + severity progression) after 2 years (p < 0.05 for both). ΔEBT had an AUC of 0.859 (p = 0.011) with sensitivity of 66.7% and specificity of 98.1% for newly diagnosed COPD using LLN criteria. We conclude that EBT shows potential for predicting the future development of COPD in current smokers. This was best seen using LLN to diagnose COPD, adding further evidence to question the use of GOLD criteria for diagnosing COPD.

Is the Exhaled Breath Temperature Sensitive to Cigarette Smoking?

The smoking habit is accompanied by an acute inflammatory response which follows tissue injury. It would be desirable to find a non-invasive inflammatory marker that would simplify the task of studying and monitoring smokers more simply and allow us to identify populations at risk of contracting Chronic Obstructive Pulmonary Disease (COPD). Today's expectations regarding research focus on issues ranging from inflammatory markers to those of exhaled breath temperature (EBT) are considerable. That said, although the EBT has been largely studied in asthma and COPD, there have not been any studies thus far that have analysed the effect of cigarette smoking on the EBT. Bearing this in mind, in this longitudinal study we aim to analyse the EBT in current smokers, monitor the effects both of cigarette smoking on EBT and of what happens after smoking cessation. Twenty-five (25) smokers (59.5 ± 3.1 yrs, 12 M) who participated in a multi-disciplinary smoking cessation programme and 25 healthy never-smokers (58.7 ± 2.9, 13 M) underwent EBT measurement. EBT values were higher in smokers before smoking (T0) than in never-smokers [34.6 (34.2-35) vs 33.2 (32.4-33.7)°C, p < 0.001. The smokers repeated measurement 5 minutes after smoking a cigarette (T1) and 2 hours after (T2). They repeated EBC measurement after 1 week (T3) and then after 3 months (T4) from smoking cessation. EBT is higher in smokers compared to controls. EBT increases after cigarette smoking and progressively decreases with the increase of time from when the last cigarette was smoked. Thus, we can conclude that EBT is increased in smokers and also sensitive to the acute effect of cigarette smoke.

Exhaled breath temperature in elite swimmers: The effects of a training session in adolescents with or without asthma.

BACKGROUND: Cooling of the airways and inflammation have been pointed as possible mechanisms for exercise-induced asthma (EIA). We aimed to investigate the effect of training and asthma on exhaled breath temperature (EBT) of elite swimmers. METHODS: Elite swimmers annually screened (skin prick tests, spirometry before and after salbutamol inhalation, induced sputum cell counts, and methacholine bronchial challenge) at our department (n = 27) were invited to this prospective study. Swimmers who agreed to participate in the present study (n = 22, 10 with asthma) had axillary temperature and EBT measured (X-halo(®) ) before and after a swimming training session (aerobic/non-aerobic). Linear regression models were used to assess the effect of asthma and other possible explanatory variables (demographics, PD20 , baseline EBT, training intensity, axillary temperature, and the number of hours trained in that week) on EBT change. RESULTS: EBT significantly increased after training independently of lung function, airway responsiveness, and inflammation in all swimmers (mean ± SD: 0.32 ± 0.57; p = 0.016). No differences were observed between asthmatic swimmers and others. A significant correlation was observed between baseline and post-exercise EBTs (r = 0.827, p < 0.001). Asthma was not a predictor of ΔEBT after adjusting for confounders; baseline EBT was the variable most strongly associated with ΔEBT, explaining by itself alone 46% of the outcome (r(2) = 0.464). CONCLUSION: Although these are preliminary data, a relationship between airway's inflammation and respiratory heat loss during exercise could not be confirmed, suggesting that the increase in exhaled breath temperature is a physiologic rather than a pathological response to exercise.

Exhaled breath temperature in children: reproducibility and influencing factors.

OBJECTIVE: This study will investigate the reproducibility and influencing factors of exhaled breath temperature measured with the tidal breathing technique in asthmatic patients and healthy children. METHODS: Exhaled breath temperature, fractional exhaled nitric oxide, and spirometry were assessed in 124 children (63 healthy and 61 asthmatic), aged 11.2 ± 2.5 year, M/F 73/51. A modified version of the American Thoracic Society questionnaire on the child's present and past respiratory history was obtained from parents. Parents were also asked to provide detailed information on their child's medication use during the previous 4 weeks. Ear temperature, ambient temperature, and relative-ambient humidity were also recorded. RESULTS: Exhaled breath temperature measurements were highly reproducible; the second measurement was higher than the first measurement, consistent with a test-retest situation. In 13 subjects, between-session within-day reproducibility of exhaled breath temperature was still high. Exhaled breath temperature increased with age and relative-ambient humidity. Exhaled breath temperature was comparable in healthy and asthmatic children; when adjusted for potential confounders (i.e. ambient conditions and subject characteristics), thermal values of asthmatic patients exceeded those of the healthy children by 1.1 °C. Normalized exhaled breath temperature, by subtracting ambient temperature, was lower in asthmatic patients treated with inhaled corticosteroids than in those who were corticosteroid-naive. CONCLUSION: Measurements of exhaled breath temperature are highly reproducible, yet influenced by several factors. Corrected values, i.e. normalized exhaled breath temperature, could help us to assess the effect of therapy with inhaled corticosteroids. More studies are needed to improve the usefulness of the exhaled breath temperature measured with the tidal breathing technique in children.

Increase of club cell (Clara) protein (CC16) in plasma and urine after exercise challenge in asthmatics and healthy controls, and correlations to exhaled breath temperature and exhaled nitric oxide.

Exercise is known to affect the airway epithelium through dehydration, followed by a release of mediators, such as club cell (Clara) protein (CC16). The aim of this study was to follow the CC16 levels at repeated time points in plasma and urine after exercise in asthmatic subjects and controls, and to relate the findings to exhaled breath temperature (EBT) and exhaled nitric oxide (NO). Twenty-two asthmatics and 18 healthy subjects performed an exercise challenge test on a treadmill. Lung function, CC16 in plasma and urine, EBT and fractional exhaled NO were investigated before and repeatedly for 60 min after the exercise. The increase in CC16 concentration in plasma was seen already one minute after exercise (p < 0.001) and increased further after 20 (p = 0.009) until 60 min (p = 0.001). An increase in urinary levels of CC16 peaked after 30 min (p < 0.001), and declined after 60 min but were still higher than baseline (p = 0.002). There were no differences in plasma or urine CC16 levels between asthmatics and controls, but males had higher plasma levels compared to females (p < 0.001) at all time points. EBT peaked at 15 min (p < 0.001) and thereafter declined, and FENO50 (p < 0.0001), alveolar NO concentration (p = 0.049) and bronchial flux of NO (p = 0.0055) decreased after exercise. In conclusion, this study shows that CC16 in plasma increased during 60 min after exercise, not synchronized with CC16 levels in urine. CC16 levels in plasma correlated to EBT and exhaled NO, reflecting an overall epithelial involvement. There was no difference between asthmatics and healthy controls, showing a physiological rather than pathophysiological response.