Physiological Modeling for Analysis of Exhaled Breath

King, Julian; Koc, Helin; Unterkofler, Karl; Teschl, Susanne; Mochalski, Paweł; Hinterhuber, Hartmann; Amann, Anton

doi:10.1016/b978-0-44-462613-4.00003-9

Cited by 17 publications

(18 citation statements)

References 50 publications

(55 reference statements)

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“…It is important to keep in mind that exhaled breath concentrations of substances only represent a proxy of the plasma concentration. Furthermore, there is evidence that the end-tidal breath concentration of substances and the underlying alveolar levels may be not identical, a factor which may have been revoked by data from our training set (39 ). In the light of these unknowns, our results were surprisingly accurate and allowed longitudinal measurements of high quality.…”

Section: Physiological Considerationsmentioning

confidence: 78%

Real-Time Quantification of Amino Acids in the Exhalome by Secondary Electrospray Ionization–Mass Spectrometry: A Proof-of-Principle Study

et al. 2016

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BACKGROUND:Amino acids are frequently determined in clinical chemistry. However, current analysis methods are time-consuming, invasive, and suffer from artifacts during sampling, sample handling, and sample preparation. We hypothesized in this proof-of-principle study that plasma concentrations of amino acids can be estimated by measuring their concentrations in exhaled breath. A novel breath analysis technique described here allows such measurements to be carried out in real-time and noninvasively, which should facilitate efficient diagnostics and give insights into human physiology.

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Section: Physiological Considerationsmentioning

confidence: 78%

Real-Time Quantification of Amino Acids in the Exhalome by Secondary Electrospray Ionization–Mass Spectrometry: A Proof-of-Principle Study

et al. 2016

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“…Nevertheless, the normal chemical ionization scheme of PTR-MS with H + is selective to VOCs with proton affinities higher than water (166.5 kcal mol −1 ). Methane (with a proton affinity of 129.9 kcal mol −1 ) is detectable by PTR-MS only with O 2 + as precursor as presented in a preliminary, non-quantitative measurement of methane during exercise on an ergometer [18].…”

Section: Introductionmentioning

confidence: 99%

Exhaled methane concentration profiles during exercise on an ergometer

et al. 2015

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Exhaled methane concentration measurements are extensively used in medical investigation of certain gastrointestinal conditions. However, the dynamics of endogenous methane release is largely unknown. Breath methane profiles during ergometer tests were measured by means of a photoacoustic spectroscopy based sensor. Five methane-producing volunteers (with exhaled methane level being at least 1 ppm higher than room air) were measured. The experimental protocol consisted of 5 min rest--15 min pedalling (at a workload of 75 W)--5 min rest. In addition, hemodynamic and respiratory parameters were determined and compared to the estimated alveolar methane concentration. The alveolar breath methane level decreased considerably, by a factor of 3-4 within 1.5 min, while the estimated ventilation-perfusion ratio increased by a factor of 2-3. Mean pre-exercise and exercise methane concentrations were 11.4 ppm (SD:7.3) and 2.8 ppm (SD:1.9), respectively. The changes can be described by the high sensitivity of exhaled methane to ventilation-perfusion ratio and are in line with the Farhi equation.

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“…Chemical ionization mass spectrometers, such as proton transfer reaction mass spectrometry (PTR-MS) and selected ion flow mass spectrometry (SIFT-MS) enable the online tracking of compounds and determination of concentration changes in single ppb levels, even with breath-to-breath resolution. King et al examined the changes of acetone and isoprene levels in different physiological processes (exercise, sleep) and developed models under consideration of the affecting ventilator, cardiovascular, and endocrine factors [81][82][83].…”

Section: Techniques For Detecting Breath Acetonementioning

confidence: 99%

Breath acetone as a potential marker in clinical practice

Ruzsányi

Kalapos²

2017

J. Breath Res.

141

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In recent decades, two facts have changed the opinion of researchers about the function of acetone in humans. Firstly, it has turned out that acetone cannot be regarded as simply a waste product of metabolism, because there are several pathways in which acetone is produced or broken down. Secondly, methods have emerged making possible its detection in exhaled breath, thereby offering an attractive alternative to investigation of blood and urine samples. From a clinical point of view the measurement of breath acetone levels is important, but there are limitations to its wide application. These limitations can be divided into two classes, technical and biological limits. The technical limits include the storage of samples, detection threshold, standardization of clinical settings, and the price of instruments. When considering the biological ranges of acetone, personal factors such as race, age, gender, weight, food consumption, medication, illicit drugs, and even profession/class have to be taken into account to use concentration information for disorders. In some diseases such as diabetes mellitus and lung cancer, as well as in nutrition-related behavior such as starvation and ketogenic diet, breath acetone has been extensively examined. At the same time, there is a lack of investigations in other cases in which ketosis is also evident, such as in alcoholism or an inborn error of metabolism. In summary, the detection of acetone in exhaled breath is a useful and promising tool for diagnosis and it can be used as a marker to follow the effectiveness of treatments in some disorders. However, further endeavors are needed for clarification of the exact distribution of acetone in different body compartments and evaluation of its complex role in humans, especially in those cases in which a ketotic state also occurs. RECEIVED

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Physiological Modeling for Analysis of Exhaled Breath

Cited by 17 publications

References 50 publications

Real-Time Quantification of Amino Acids in the Exhalome by Secondary Electrospray Ionization–Mass Spectrometry: A Proof-of-Principle Study

Real-Time Quantification of Amino Acids in the Exhalome by Secondary Electrospray Ionization–Mass Spectrometry: A Proof-of-Principle Study

Exhaled methane concentration profiles during exercise on an ergometer

Breath acetone as a potential marker in clinical practice

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