Exhaled breath temperature, a new biomarker in asthma control: a pilot study

Measurement of exhaled breath temperature in patients under general anesthesia: A feasibility study

The aim of the present study was to investigate the respiratory parameters that influence the exhaled breath temperature (EBT) and the feasibility of using the latter to monitor the core temperature under general endotracheal anesthesia. A total of 20 patients undergoing abdominal surgery were included in the present study. At the first stage of the experiment, the respiratory rate was adjusted, while the other respiratory parameters [tidal volume, inspiratory and expiratory time ratio (TI:TE), and positive end expiratory pressure (PEEP)] were maintained at a constant level. At the second stage, the tidal volume was adjusted, while the other respiratory parameters were maintained at a constant level. At the third stage, the TI:TE was adjusted, while the other parameters were maintained at a constant level. At the fourth stage, PEEP was adjusted, while the other parameters were maintained at a constant level. In each experiment, the EBT, the maximum temperature of exhaled air in each min, the inhaled air temperature and the nasopharyngeal temperature (T nose) were recorded every min. During the first stage of the experiment, no significant difference was noted in the EBT at different levels of respiratory rate. During the second, third and fourth stage, no significant difference was noted in the EBT at different tidal volumes, TI:TE and PEEP, respectively. The EBT was significantly correlated with the T nose. Overall, the present study demonstrated that the EBT of patients undergoing abdominal surgery under general endotracheal anesthesia was not affected by the examined respiratory parameters and that it could be considered a feasible method of monitoring core temperature.

Review of the algorithms used in exhaled breath analysis for the detection of diabetes

Currently, intensive work is underway on the development of truly noninvasive medical diagnostic systems, including respiratory analysers based on the detection of biomarkers of several diseases including diabetes. In terms of diabetes, acetone is considered as a one of the potential biomarker, although is not the single one. Therefore, the selective detection is crucial. Most often, the analysers of exhaled breath are based on the utilization of several commercially available gas sensors or on specially designed and manufactured gas sensors to obtain the highest selectivity and sensitivity to diabetes biomarkers present in the exhaled air. An important part of each system are the algorithms that are trained to detect diabetes based on data obtained from sensor matrices. The prepared review of the literature showed that there are many limitations in the development of the versatile breath analyser, such as high metabolic variability between patients, but the results obtained by researchers using the algorithms described in this paper are very promising and most of them achieve over 90% accuracy in the detection of diabetes in exhaled air. This paper summarizes the results using various measurement systems, feature extraction and feature selection methods as well as algorithms such as Support Vector Machines, k-Nearest Neighbours and various variations of Neural Networks for the detection of diabetes in patient samples and simulated artificial breath samples.

Artificial Breath Classification Using XGBoost Algorithm for Diabetes Detection

Exhaled breath analysis has become more and more popular as a supplementary tool for medical diagnosis. However, the number of variables that have to be taken into account forces researchers to develop novel algorithms for proper data interpretation. This paper presents a system for analyzing exhaled air with the use of various sensors. Breath simulations with acetone as a diabetes biomarker were performed using the proposed e-nose system. The XGBoost algorithm for diabetes detection based on artificial breath analysis is presented. The results have shown that the designed system based on the XGBoost algorithm is highly selective for acetone, even at low concentrations. Moreover, in comparison with other commonly used algorithms, it was shown that XGBoost exhibits the highest performance and recall.

Requirements for Supporting Diagnostic Equipment of Respiration Process in Humans

There is abundant worldwide research conducted on the subject of the methods of human respiration process examination. However, many of these studies describe methods and present the results while often lacking insight into the hardware and software aspects of the devices used during the research. This paper’s goal is to present new equipment for assessing the parameters of human respiration, which can be easily adopted for daily diagnosis. This work deals with the issue of developing the correct method of obtaining measurement data. The requirements of the acquisition parameters are clearly pointed out and examples of the medical applications of the described device are shown. Statistical analysis of acquired signals proving its usability is also presented. In the examples of selected diseases of the Upper Respiratory Tract (URT), the advantages of the developed apparatus for supporting the diagnosis of URT patency have been proven.

Community Use of Face Masks against the Spread of COVID-19

The role of face masks to prevent and control COVID-19 is critical, especially since asymptomatic or pre-symptomatic infected individuals can shed high loads of SARS-CoV-2 in the surrounding environment. In addition to being a two-way barrier to protect against virions droplets both in terms of "source control" (for the benefits of the community) and "physical protection" (for wearer), face masks also allow maintaining physiological temperatures and humidity of the nasal cavity and mouth, independently from the external environmental conditions. Beyond compromising the viral transmission speed, exposure to cold environments could have a detrimental effect on the host's susceptibility to SARS-CoV-2. The innate human immune system becomes in fact weaker with cooler nose temperatures and thus more vulnerable to viral replication. Furthermore, there is evidence that warm, humid climates are associated with reduced spread of SARS-CoV-2, while cold dry conditions favor its stability and transmissibility. In the early stage of a viral infection, a physiological body temperature in the upper airways supports the innate immune system, endorsing the muco-ciliary clearance, inhibiting, or deactivating any first settlement of viruses. Face masks are therefore strongly recommended also outdoors, especially under cold weather conditions, not only as a physical barrier against the transmission of SARS-CoV-2, but also to prevent the rapid cooling of the nasal mucosa and the inhibition of the human innate defense of the upper airways.

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.

[Predictive significance of exhaled breath temperature for airway inflammation changes in children with asthma]

OBJECTIVE

To explore the predictive significance of exhaled breath temperature (EBT) for airway inflammation changes in children with asthma.

METHODS

A total of 60 children with asthma who met the inclusion criteria at the first visit were chosen as the asthma group, and 60 healthy children were selected as the control group. The EBT level was measured by the latest third-generation product (X-halo). The Childhood Asthma Control Test (C-ACT) score was recorded. EBT level and C-ACT score were compared between the asthma and control groups. At the subsequent visit one month later, the children were divided into well-controlled, partially-controlled, and uncontrolled groups according to their C-ACT scores. The EBT level and the FeNO level of the three groups were measured. EBT level and C-ACT score were compared among the three groups. The correlation between EBT and FeNO was analyzed. The data of initial diagnosis were reviewed, the EBT level and C-ACT score at the first visit were compared among the three groups, and the differences in EBT level and C-ACT score among the three groups at the second and first visits were evaluated.

RESULTS

At the first visit, the asthma group had a significantly higher EBT and a significantly lower C-ACT score compared with the control group (P<0.05). At the time of the subsequent visit, there was a significant difference in EBT level between the three groups, i.e., uncontrolled group > partially-controlled group > well-controlled group (P<0.05), and there was also a significant difference in C-ACT score between the three groups, i.e., well-controlled group > partially-controlled group > uncontrolled group (P<0.05). There were no significant differences in EBT level and C-ACT score at the first visit between the three groups. From the first visit to the subsequent visit, EBT level was significantly decreased in the well-controlled group (P<0.05), but significantly increased in both partially-controlled group uncontrolled groups (P<0.05); C-ACT score was significantly increased in the well-controlled and partially-controlled groups (P<0.05), but significantly decreased in the uncontrolled group (P<0.05). EBT and FeNO levels at the subsequent visit were positively correlated with each other in the uncontrolled group (P<0.05).

CONCLUSIONS

EBT has predictive significance for the changes in airway inflammation in children with asthma.

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.

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.

Athletes Do Not Condition Inspired Air More Effectively than Nonathletes during Hyperpnea

Endurance athletes have a high prevalence of airway diseases, some possibly representing adaptive mechanisms to the need of conditioning large volumes of inspired air during high ventilation in specific environments. The aim of this study is to assess the ability to condition (warm and humidify) inspired air in athletes by measuring the difference between inhaled and exhaled air temperature (ΔT) during and after eucapnic voluntary hyperpnea (EVH) test.

METHODS

Twenty-three endurance athletes from various sports, 12 with airway hyperresponsiveness (AHR) and/or exercise-induced bronchoconstriction (EIB) (A+), 11 without AHR and/or EIB (A-), 12 nonathletes with AHR and/or EIB (C+), and 11 nonathletes without AHR and/or EIB (C-) were recruited. All subjects attended the laboratory on three occasions, twice for baseline characterization, including questionnaires, pulmonary function, methacholine bronchoprovocation, allergy skin prick tests, exhaled nitric oxide measurement, and a standard EVH, and once to perform a modified EVH to assess ΔT. Inspired and expired air temperatures were measured with a high-precision probe during EVH and at regular intervals until 30 min after the end of the test.

RESULTS

The global ΔT during the EVH was +5.8°C ± 1.5°C and +4.7°C ± 1.5°C during the 30 min after the EVH. No difference was found between groups for either the ΔT or the slope of ΔT, during and after the EVH.

CONCLUSION

This study shows no evidence of improved capacity to condition inspired air in endurance athletes, which could have suggested an increased bronchial blood flow or another adaptive mechanism. The absence of an adaptive mechanism could therefore contribute to airway damage observed in athletes in allowing colder but mainly dryer air to penetrate deeper in the lung.

The added value of exhaled breath temperature in respiratory medicine

Recognition of the huge economic burden chronic respiratory diseases pose for society motivated fundamental and clinical research leading to insight into the role of airway inflammation in various disease entities and their phenotypes. However, no easy, cheap and patient-friendly methods to assess it have found a place in routine clinical practice. Measurement of exhaled breath temperature (EBT) has been suggested as a non-invasive method to detect inflammatory processes in the airways as a result of increased blood flow within the airway walls. As EBT values are within a narrow range, the thermometers designed for the purpose of assessing it need to be precise and very sensitive. EBT increases linearly over the pediatric age range and seems to be influenced by gender, but not by height and body weight. In non-smoking individuals with no history of respiratory disease EBT has a natural circadian peak about noon and increases with food intake and physical exercise. When interpreting EBT in subjects with alleged airway pathology, the possibilities of tissue destruction (chronic obstructive pulmonary disease, cystic fibrosis) or excessive bronchial obstruction and air trapping (severe asthma) need to be considered, as these conditions drive (force) EBT down. A prominent advantage of the method is to assess EBT when patients are in a steady state of their disease and to use this 'personal best' to monitor them and guide their treatment. Individual devices outfitted with microprocessors and memory have been created, which can be used for personalized monitoring and disease management by telemedicine.

Evaluation of exhaled breath temperature (EBT) as a marker and predictor of asthma exacerbation in children and adolescents

INTRODUCTION

Noninvasive and easy-to-use tools to monitor airway inflammation in asthma are needed to maintain disease control, particularly in pediatric population. The aim of the study was to evaluate exhaled breath temperature (EBT) in pediatric respiratory clinic setting.

METHODS

We evaluated 37 children and adolescents with asthma (5-17 years; median: 11 years). The patients were followed up in stable condition and during exacerbations (paired observations in n = 19 subjects). We evaluated medication use, EBT, fractional exhaled nitric oxide (FeNO), spirometry and atopic status of patients.

RESULTS

EBT was significantly higher in children with asthma exacerbation {entire group: median [interquartile range (IQR)]: 32.3 [1.1]°C vs. 33.8 [1.7]°C; p < 0.001 and mean ± SD: 33.1 ± 1.0°C vs. 33.6 ± 1.1°C; p = 0.038 for paired observations}. Significant correlation was observed between EBT and FeNO in the entire group (r = 0.22; p = 0.03). No difference was observed in EBT median values in atopic and non-atopic subjects in the entire group (median [IQR]: 32.6 [1.6] vs. 32.7 [2.0]; p = 0.88) and in subgroups. There was no difference in EBT values in patients receiving systemic or inhaled glucocorticosteroids (p = 0.45 and 0.83). There was no significant correlation between EBT and body or room temperature. The only significant predictor of exacerbation in logistic regression model was EBT {aOR = 2.4; 95% [confidence interval (CI)]: 1.4-4.1}. ROC analysis demonstrated applicability of EBT as a marker of asthma exacerbation in children (AUC = 0.748; p < 0.001; cut-off = 33.3°C; sensitivity: 64.3%; specificity: 82.1%).

CONCLUSIONS

We suggest that EBT may serve as marker and predictor of asthma exacerbation in children. EBT follow-up may be useful in asthma monitoring in children and adolescents.

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.

Usefulness of the Exhaled Breath Temperature Plateau in Asthma Patients

BACKGROUND

Exhaled breath temperature (EBT) has recently been proposed as a noninvasive marker of bronchial inflammation in patients with asthma. However, the usefulness of EBT in everyday clinical practice is not well established. Results to date are contradictory and are mainly derived from small, pediatric populations. A comparison of results is further complicated by the use of different equipment and measurements.

OBJECTIVE

We performed a comprehensive study to determine whether EBT is related to asthma control, disease severity, bronchial obstruction, or bronchial inflammation.

METHODS

Sixty-nine patients on maintenance treatment for asthma were included in a cross-sectional study. At the same visit, we measured the EBT plateau (EBTp) using an X-halo Breath Thermometer (Delmedica, Singapore), the fraction of exhaled nitric oxide (FeNO), spirometry, and inflammatory cell count in induced sputum, and we administered the Asthma Control Test questionnaire.

RESULTS

No significant differences were found between EBTp measurements and the level of asthma control, disease severity, bronchial obstruction, FeNO levels, or inflammatory asthma phenotypes. We found a significant difference between EBTp and gender. The EBTp was 34.07°C (SD 0.74) in women and 34.38°C (0.46) in men (p = 0.038). We also found a significant correlation between EBTp measurements and the induced sputum eosinophil count (R = -0.348, p = 0.003).

CONCLUSIONS

The results of this study do not support the usefulness of the EBTp in asthma management in routine clinical practice. Further research using standardized methods is needed to determine the potential use of the EBTp measurement in asthma management.

Tidal-breathing measurement of exhaled breath temperature (EBT) in schoolchildren

BACKGROUND

Non-invasive assessment of airway inflammation is particularly useful in children. The exhaled breath temperature (EBT) may reflect inflammatory vasodilation and serve to assess respiratory symptoms and therapy with inhaled corticosteroids (ICs).

AIMS

To compare EBT with other non-invasive measurements in unselected schoolchildren in relation to respiratory symptoms and IC-therapy, as well as to assess reproducibility, and potentially influencing factors.

METHODS

In 298 Italian schoolchildren, we assessed tidal-EBT, FE(NO), spirometry, skin-prick tests, questionnaires on chronic respiratory symptoms, and medication. Subjects were divided as follows: reported wheeze, respiratory symptoms other than wheeze, and without symptoms.

RESULTS

Subjects with reported wheeze (n = 30) more frequently presented atopy, respiratory symptoms, higher FE(NO), lower lung function than subjects with symptoms other than wheeze (n = 141) and those without symptoms (n = 127), but had a similar EBT. IC-treated children (5 wheeze, 9 respiratory symptoms other than wheeze, 4 without chronic symptoms) had lower median (interquartile range) EBT levels than IC-untreated children (n = 280) [EBT: 31.7 (30.1-32.5) vs. 32.6 (31.4-33.4), P = 0.027]. Duplicate EBT measurements were highly reproducible (ICC = 0.94). In a multiple linear-regression model, EBT was explained by age, weight, duration of EBT measurement, FE(NO), and ambient temperature (r = 0.63, P < 0.001).

CONCLUSION

Tidal-EBT measurements are easy to perform, reproducible, though symptom misclassification may affect the results obtained regarding the effect of IC therapy. Factors influencing EBT should be addressed in further epidemiological studies.

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.

Exhaled breath temperature in asthmatics and controls after eucapnic voluntary hyperventilation and a methacholine challenge test

BACKGROUND

It has been suggested that exhaled breath temperature (EBT) is increased in asthmatic subjects.

OBJECTIVES

Our aim was to investigate EBT in asthmatics compared to healthy controls before and after eucapnic voluntary hyperventilation (EVH) and a methacholine challenge test (MCT).

METHODS

A total of 26 asthmatics and 29 healthy controls were included. Forced expiratory volume in 1 s (FEV1), EBT and oral, axillary and auricular temperatures were measured before and after EVH and MCT.

RESULTS

FEV1 % predicted (%p) was significantly lower in asthmatic subjects compared to healthy controls at all time points. EBT was significantly increased in all subjects 15-30 min after EVH and 5-45 min after MCT. Oral temperature displayed a similar pattern of increase, in contrast to axillary and auricular temperature, and correlated with EBT before and after both of the challenge tests. EBT after 5 min correlated with the largest drop in FEV1%p after EVH in asthmatic subjects. No significant differences or changes in EBT were found when comparing asthmatics to healthy controls before or after any of the tests.

CONCLUSIONS

EBT is increased after both EVH and MCT, possibly reflecting a vascular response. This is related to both the fall in FEV1 and to oral temperature, suggesting an effect on the whole respiratory tract including the oral cavity. No differences in EBT are seen between asthmatics and healthy controls, indicating that the increase in EBT is mainly physiological rather than pathophysiological.

Exhaled breath temperature increases after exercise in asthmatics and controls

BACKGROUND

Exhaled breath temperature (EBT) has been suggested as a marker of airway inflammation in asthma.

OBJECTIVES

The aim of the present study was to investigate EBT in asthmatic subjects compared to healthy controls after an exercise challenge test, and in subjects with exercise-induced bronchoconstriction compared to subjects without, and to compare with body temperatures.

METHODS

A total of 21 healthy controls and 20 asthmatics were included. Forced expiratory volume in 1 s (FEV(1)), EBT and oral, axillary and auricular temperatures were measured before and after an exercise challenge test.

RESULTS

FEV(1) % predicted (%p) was significantly lower in asthmatic subjects compared to healthy controls at all time points after exercise. The largest drop in FEV(1)%p correlated with EBT after 5 min. EBT increased markedly 5 min after exercise and remained high for at least 60 min. In asthmatics whose FEV(1) dropped by >10%, EBT was higher after 60 min compared to the remaining asthmatics. EBT correlated with oral temperature at all time points after exercise, with axillary temperature only at 15, 30 and 60 min, and not at all with auricular temperature.

CONCLUSIONS

EBT is increased after exercise, and elevated EBT correlated with a drop in FEV(1)%p. The immediate increase in EBT did not differ between asthmatics and controls but remained elevated in the asthmatics whose FEV(1) dropped by >10%, indicating a different vascular response.

A survey of recently published cardiovascular, hematological and pneumological original articles in the Brazilian scientific press

Recent original scientific contributions published in selected Brazilian periodicals and classifiable under cardiovascular and pulmonary subject categories cover a wide range of sub specialties, both clinical and experimental. Because they appear in journals with only recently enhanced visibility, we have decided to highlight a number of specific items appeared in four Brazilian journals, because we understand that this is an important subsidy to keep our readership adequately informed. These papers cover extensive sub-areas in both fields.