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

Abstract

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.

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

“…Previous studies have reported that the EBT of patients with asthma is higher than that of healthy subjects (22,23). These studies reported a correlation between EBT and the level of exhaled nitric oxide, which is an inflammatory marker present in asthmatics (24).…”

“…It has previously been hypothesized that the level of EBT is related to the degree of airway inflammation (22,23,28,29). Previous studies have shown that EBT is increased in asthmatic children (30)(31)(32)(33) and in patients with non-small cell lung cancer (34), as well as in patients exhibiting exacerbated COPD (35); therefore, patients who presented with the aforementioned diseases were excluded in the present study.…”

Pediatric pulmonology 2019 year in review: Asthma

“…A group of investigators measured exhaled breath temperature amongst children hospitalized with an asthma exacerbation as well as upon recovery. 10 They found that there was a significant decrease in exhaled breath temperature after recovery from the asthma exacerbation as well as correlation with peak expiratory flow rate. However, in individual patients, exhaled breath temperature did not correlate with FEV1, fractional excretion of nitric oxide, or sputum eosinophil count.…”

“…One such modality is exhaled breath temperature. A group of investigators measured exhaled breath temperature amongst children hospitalized with an asthma exacerbation as well as upon recovery 10 . They found that there was a significant decrease in exhaled breath temperature after recovery from the asthma exacerbation as well as correlation with peak expiratory flow rate.…”