Slower rise of exhaled breath temperature in chronic obstructive pulmonary disease

Paredi, Paolo; Caramori, Gaetano; Cramer, Derek; Ward, Simon; Ciaccia, A.; Papi, Alberto; Kharitonov, Sergei A.; Barnes, Peter J.

doi:10.1183/09031936.03.00061902

Cited by 30 publications

(15 citation statements)

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“…Other studies found no association between exhaled breath temperature and age in children (age range: 9–11 years, n = 60) [30] and the exhaled air temperature was not statistically different in a relatively underpowered study of younger (20 ± 6 years, n = 8) compared to older (55 ± 9 years, n = 6) adults [31]. …”

Section: Discussionmentioning

confidence: 99%

Host and environmental predictors of exhaled breath temperature in the elderly

et al. 2013

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BackgroundExhaled breath temperature has been suggested as a new method to detect and monitor pathological processes in the respiratory system. The putative mechanism of this approach is based upon changes in the blood flow. So far potential factors that influence breath temperature have not been studied in the general population.MethodsThe exhaled breath temperature was measured in 151 healthy non-smoking elderly (aged: 60–80 years) at room temperature with the X-halo device with an accuracy of 0.03°C. We related exhaled breath temperature by use of regression models with potential predictors including: host factors (sex, age) and environmental factors (BMI, physical activity, and traffic indicators).ResultsExhaled breath temperature was lower in women than in men and was inversely associated with age, physical activity. BMI and daily average ambient temperature were positively associated with exhaled breath temperature. Independent of the aforementioned covariates, exhaled breath temperature was significantly associated with several traffic indicators. Residential proximity to major road was inversely associated with exhaled breath temperature: doubling the distance to the nearest major intense road was observed a decrease of 0.17°C (95% CI: -0.33 to -0.01; p = 0.036).ConclusionsExhaled breath temperature has been suggested as a noninvasive method for the evaluation of airway inflammation. We provide evidence that several factors known to be involved in proinflammatory conditions including BMI, physical activity and residential proximity to traffic affect exhaled breath temperature. In addition, we identified potential confounders that should be taken into account in clinical and epidemiological studies on exhaled breath temperature including sex, age, and ambient temperature.

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Section: Discussionmentioning

confidence: 99%

Host and environmental predictors of exhaled breath temperature in the elderly

et al. 2013

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“…There is a report that EBT is shifting downwards in patients with chronic obstructive pulmonary disease, in whom airways and pertaining vasculature are reduced [12]. We have preliminary yet unpublished data of increased EBT (but not axillary temperature) in cases with viral infections, tuberculosis and bronchopneumonia.…”

Section: Applicability Of the Ebt Device In Medicinementioning

confidence: 69%

Development of an Individual Device for Exhaled Breath Temperature Measurement

Popov¹,

Kralimarkova²,

Tzachev³

et al. 2010

IEEE Sensors J.

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Different thermometers have been constructed over the decades to measure the temperature of the body to help detect and monitor morbid states. They yield slightly different estimates of the core body temperature depending on the proximity of the measurement site to the internal milieu of the organism, the principle of temperature assessment, and the specific characteristics of the gauging devices. Evaluation of the exhaled breath temperature (EBT) has been recently suggested as a new method to detect inflammatory processes in the conducting airways due to changes in the blood flow perfusion of their walls and adjacent structures. While the first reported EBT experiments required sealed laboratory environment and sophisticated equipment, we designed a simple handheld instrument for EBT measurement and proven its precision, reproducibility and validity in subjects with asthma. We now describe the construction principles of our instrument, the procedure to test the fitness for purpose of the separate units and the novel features of the newest prototypes outfitted with microprocessor and memory. We also outline the potential clinical applications of an individual device for EBT measurement.Index Terms-Airway inflammation, clinical applications, core body temperature, exhaled breath temperature, thermometry.

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“…Innes point out that we did not report the method of flow targeting. However, after describing the exhalation manoeuvre as flow and pressure controlled, we refer the reader to a previous publication by our group in which all the details related to the pressure (4 cmH 2 O) and flow control (visual feedback) are fully described (see reference [14] in the text of [1]). …”

Section: From the Authorsmentioning

confidence: 99%

“…Innes for their interest and constructive criticism relating to our paper which reported low exhaled breath temperature gradients in chronic obstructive pulmonary disease patients compared to normal subjects [1].…”

Section: From the Authorsmentioning

confidence: 99%

“…Innes make further comments regarding our manuscript stating that because we did not control the exhalation flow rate our measurements actually reflect expiratory pattern rather than heat exchange. However, we did control exhalation flow rate (see above and see the Methods section in the manuscript [1]). Furthermore, a more thorough reading of the literature would have shown that expiratory air at the mouth is little influenced by ventilation rate [6] and pattern (tidal volume and respiratory rate changes with the same minute ventilation) [7].…”

Section: From the Authorsmentioning

confidence: 99%

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From the Authors

Paredi¹,

Kharitonov²,

Barnes³

2003

Eur Respir J

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References 1.Paredi P, Caramori G, Cramer D, et al. From the authors:We would like to thank J.B. McCafferty and J.A. Innes for their interest and constructive criticism relating to our paper which reported low exhaled breath temperature gradients in chronic obstructive pulmonary disease patients compared to normal subjects [1].J.B. McCafferty and J.A. Innes suggest that it is controversial that bronchial blood flow has a role in airway heat exchange. We disagree and would like to draw their attention to numerous papers that demonstrated the opposite effect. First, it has been shown that changes in airway blood volume are reflected in fluctuations in intra-thoracic heat exchange, whereas even large increases in blood flow through the pulmonary circulation do not influence airstream temperature [2]. This proves that bronchial and not pulmonary blood flow plays a major role in airway heat exchange. Secondly, changes in bronchial blood flow can alter airway responsiveness and temperature [3], confirming that the bronchial circulation may control airstream temperature and contribute to airway narrowing. Thirdly, temperature changes induce bronchoconstriction, which can be prevented by reducing mucosal blood supply using inhaled vasoconstrictors [3], indicating that airway temperature and bronchial blood flow are correlated. Furthermore, preliminary data presented as an oral presentation at the American Thoracic Society meeting in Atlanta last year by our group showed a correlation between bronchial blood flow, measured noninvasively by an inhaled soluble gas technique, and exhaled breath temperature gradients [4]. Therefore, there is substantial evidence that airway blood flow is the major determinant of airway heat exchange.In their letter, J.B. McCafferty and J.A. Innes also state that heat transfer occurs in the upper airways (above the glottis) when breathing normally at room temperature. They quote a manuscript published in 1953 by COLE [5], but they have not interpreted the manuscript correctly and have ignored more recent publications by the same author. Even though we agree that inspired air is mostly conditioned in the upper airways, in our study we concentrated on exhaled air. The work of COLE [6] has demonstrated that "during expiration heat and water are returned to the exhaled air along the whole of the respiratory tract", including the bronchial tree. We would also like to stress that the patients included in our study, as described in the method session, were not "respiring at low flow rates" as indicated by J.B. McCafferty and J.A. Innes. Rather, they were breathing normally at tidal volume before being asked to exhale at a constant exhalation flow rate (10 L?min -1 ) after a deep inhalation to total lung capacity.Regarding the methodology for the measurement of exhaled breath temperature gradients, J.B. McCafferty and J.A. Innes point out that we did not report the method of flow targeting. However, after describing the exhalation manoeuvre as flow and pressure controlled, we refer the reader to a ...

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Slower rise of exhaled breath temperature in chronic obstructive pulmonary disease

Cited by 30 publications

References 32 publications

Host and environmental predictors of exhaled breath temperature in the elderly

Host and environmental predictors of exhaled breath temperature in the elderly

Development of an Individual Device for Exhaled Breath Temperature Measurement

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