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A Single Breath Method to Assess the Relative Contribution of Central and Peripheral Airways to Overall Exhaled Breath Temperature

2015; Elsevier BV; Volume: 135; Issue: 2 Linguagem: Inglês

10.1016/j.jaci.2014.12.1514

1097-6825

Todor A. Popov, Diana Hristova, Tanya Kralimarkova, Dimitar Popov, Andrey Popov, Simeon Uzunov, Vasil Dimitrov, L. DuBuske,

Respiratory and Cough-Related Research

RationaleMultiple exhalations can be used to discriminate between central (Caw) and peripheral airways (Paw) and assess the contribution of each to disease states. As multiple breathing maneuvers are time consuming and induced subjective discomfort, this study assesses a method of using a single deep breath maneuver.MethodsThe equipment employed included a fast reacting inflatable balloon valve system operated by computer which steers the expired airflow through channels with sensitive temperature sensors. During initial deep inhalation, the inspired volume is measured and the sequence of valve openings is adjusted to yield volumes of air characteristic of Caw or Paw during expiration. Absolute differences of and ratios between EBT of Caw and Paw were calculated and compared in 6 partly controlled asthmatics and 6 healthy controls.ResultsThe absolute differences between EBT of Paw and Caw ranged from 1.82 ºC and 3.45 ºC, with a median of 2.19ºC in the healthy controls and from 3.22ºC and 4.56ºC, with a median of 4.03ºC in the asthmatics (P=0.019). The Paw/Caw ratios showed a trend of higher EBT in Paw of asthmatics, but the differences did not reach statistical significance due to the small number of subjects. The reproducibility of the measurements was high and the subjects did not experience any subjective discomfort.ConclusionsMeasuring differences between central and peripheral EBT by an upgraded method of short duration may allow more insight into the nature of the inflammatory processes in obstructive respiratory diseases. RationaleMultiple exhalations can be used to discriminate between central (Caw) and peripheral airways (Paw) and assess the contribution of each to disease states. As multiple breathing maneuvers are time consuming and induced subjective discomfort, this study assesses a method of using a single deep breath maneuver. Multiple exhalations can be used to discriminate between central (Caw) and peripheral airways (Paw) and assess the contribution of each to disease states. As multiple breathing maneuvers are time consuming and induced subjective discomfort, this study assesses a method of using a single deep breath maneuver. MethodsThe equipment employed included a fast reacting inflatable balloon valve system operated by computer which steers the expired airflow through channels with sensitive temperature sensors. During initial deep inhalation, the inspired volume is measured and the sequence of valve openings is adjusted to yield volumes of air characteristic of Caw or Paw during expiration. Absolute differences of and ratios between EBT of Caw and Paw were calculated and compared in 6 partly controlled asthmatics and 6 healthy controls. The equipment employed included a fast reacting inflatable balloon valve system operated by computer which steers the expired airflow through channels with sensitive temperature sensors. During initial deep inhalation, the inspired volume is measured and the sequence of valve openings is adjusted to yield volumes of air characteristic of Caw or Paw during expiration. Absolute differences of and ratios between EBT of Caw and Paw were calculated and compared in 6 partly controlled asthmatics and 6 healthy controls. ResultsThe absolute differences between EBT of Paw and Caw ranged from 1.82 ºC and 3.45 ºC, with a median of 2.19ºC in the healthy controls and from 3.22ºC and 4.56ºC, with a median of 4.03ºC in the asthmatics (P=0.019). The Paw/Caw ratios showed a trend of higher EBT in Paw of asthmatics, but the differences did not reach statistical significance due to the small number of subjects. The reproducibility of the measurements was high and the subjects did not experience any subjective discomfort. The absolute differences between EBT of Paw and Caw ranged from 1.82 ºC and 3.45 ºC, with a median of 2.19ºC in the healthy controls and from 3.22ºC and 4.56ºC, with a median of 4.03ºC in the asthmatics (P=0.019). The Paw/Caw ratios showed a trend of higher EBT in Paw of asthmatics, but the differences did not reach statistical significance due to the small number of subjects. The reproducibility of the measurements was high and the subjects did not experience any subjective discomfort. ConclusionsMeasuring differences between central and peripheral EBT by an upgraded method of short duration may allow more insight into the nature of the inflammatory processes in obstructive respiratory diseases. Measuring differences between central and peripheral EBT by an upgraded method of short duration may allow more insight into the nature of the inflammatory processes in obstructive respiratory diseases.