| 1. |
- Högman, Marieann, et al.
(author)
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Effects of growth and aging on the reference values of pulmonary nitric oxide dynamics in healthy subjects
- 2017
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In: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 11:4
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Journal article (peer-reviewed)abstract
- The lung just like all other organs is affected by age. The lung matures by the age of 20 and age-related changes start around middle age, at 40-50 years. Exhaled nitric oxide (FENO) has been shown to be age, height and gender dependent. We hypothesize that the nitric oxide (NO) parameters alveolar NO (CANO), airway flux (JawNO), airway diffusing capacity (DawNO) and airway wall content (CawNO) will also demonstrate this dependence. Data from healthy subjects were gathered by the current authors from their earlier publications in which healthy individuals were included as control subjects. Healthy subjects (n = 433) ranged in age from 7 to 78 years. Age-stratified reference values of the NO parameters were significantly different. Gender differences were only observed in the 20-49 age group. The results from the multiple regression models in subjects older than 20 years revealed that age, height and gender interaction together explained 6% of variation in FENO at 50 ml s-1 (FENO50), 4% in JawNO, 16% in CawNO, 8% in DawNO and 12% in CANO. In conclusion, in this study we have generated reference values for NO parameters from an extended NO analysis of healthy subjects. This is important in order to be able to use these parameters in clinical practice.
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| 2. |
- Lindberg, Lars, et al.
(author)
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The advantages of standardizing exhaled breath-alcohol concentration to a reference respiratory gas—water vapor
- 2023
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In: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 17:1
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Research review (peer-reviewed)abstract
- Measuring the concentration of alcohol (ethanol) in exhaled breath (BrAC) provides a rapid and non-invasive way to determine the co-existing concentration in arterial blood (A-BAC). The results of breath-alcohol testing are used worldwide as evidence of excessive drinking, such as when traffic offenders are prosecuted. Two types of breath-alcohol analyzer are in common use; hand-held instruments used as preliminary screening tests of sobriety and more sophisticated evidential instruments, the results of which are accepted as evidence for prosecution of drunken drivers. Most evidential breath-alcohol analyzers are designed to capture the last portion of a prolonged exhalation, which is thought to reflect the alcohol concentration in substantially alveolar air. The basic premise of breath-alcohol analysis is that there is a physiological relationship between A-BAC and BrAC and close agreement between the two analytical methods. This article reviews the principles and practice of breath-alcohol analysis and introduces the concept of standardizing the results to a secondary physiological gas (water vapor), which therefore serves as an internal standard. The measured BrAC is thus adjusted to an alveolar air water content of 43.95 mg l−1 at 37 °C. This has several advantages, and means that a sample of breath can be captured without the person having to blow directly into the instrument. Adjusting the breath-alcohol concentration to water vapor concentration also compensates for variations in temperature of the expired air. The contact-free method of sampling breath means that a mouthpiece is unnecessary and the test subject does not need to make a continuous end exhalation.
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| 3. |
- Bondesson, Eva, et al.
(author)
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Exhaled breath condensate-site and mechanisms of formation
- 2009
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In: Journal of Breath Research. - : IOP Publishing. - 1752-7163 .- 1752-7155. ; 3:1
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Journal article (peer-reviewed)abstract
- Exhaled breath condensate (EBC) analysis is a promising tool for diagnosis and management of pulmonary diseases. Its clinical usefulness is still limited however due to unresolved issues around e. g. reproducibility, anatomical site of origin of EBC solutes and mechanisms of EBC formation. To gain some knowledge on these issues, three different airway deposition patterns of an aqueous aerosol containing technetium-99m were studied in eight healthy non-smoking subjects. EBC was collected 20 min after each radioaerosol administration and analyzed for gamma radiation and electrolytes. Radioaerosol deposition in preferentially central lung compared with preferentially peripheral lung resulted in 3.8 times higher EBC radioactivity. EBC concentrations of Na+ and K+ correlated significantly indicating dilution by water vapor to be a major source of variability. Since Na+/K+- and Na+/S2--concentration ratios, but not Na+/Cl--or Na+/Ca2+-, were comparable to those previously reported for alveolar lining fluid (ALF), some mechanisms other than dilution are likely also to be involved. In conclusion, our findings indicate that EBC derives mainly from the central airways, that the electrolyte composition of EBC does not consistently reflect that of ALF, and that EBC concentrations of electrolytes are determined not only by ALF dilution with water vapor but also by other mechanisms.
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| 4. |
- Lindberg, Lars, et al.
(author)
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Simultaneously recorded single-exhalation profiles of ethanol, water vapour and CO2 in humans: impact of pharmacokinetic phases on ethanol airway exchange
- 2012
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In: Journal of Breath Research. - : IOP Publishing. - 1752-7163 .- 1752-7155. ; 6:3
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Journal article (peer-reviewed)abstract
- The breath alcohol concentration (BrAC) standardized to the alveolar water vapour concentration has been shown to closely predict the arterial blood alcohol (ethanol) concentration (ABAC). However, a transient increase in the ABAC/BrAC ratio has been noted, when alcohol is absorbed from the gastrointestinal tract (absorption phase) and the ABAC rapidly rises. We analysed the plot of simultaneously recorded alcohol, water vapour and CO2 against exhaled volume (volumetric expirogram) for respiratory dead space volume (VD), cumulative gas output and phase III slope within one breath to evaluate whether changes in the BrAC profile could explain this variability. Eight healthy subjects performed exhalations through pre-heated non-restrictive mouthpieces and the concentrations were measured by infrared absorption. In the absorption phase, the respiratory VD of alcohol was transiently increased and the exhaled alcohol was displaced to the latter part of the expirogram. In the post-absorption phase, the respiratory VD for alcohol and water vapour was stable and always less than the respiratory VD for CO2, indicating that the first part of the exhaled alcohol and water originated from the conducting airway. The position of the BrAC profile between water vapour and CO2 in the post-absorptive phase indicates an interaction within the conducting airway, probably including a deposition of alcohol onto the mucosa during exhalation. We conclude that the increase in the ABAC/BrAC ratio during the absorption phase of alcohol coincides with a transient increase in respiratory VD of alcohol and a delay in the appearance of alcohol in the exhaled air as the exhalation proceeds compared with the post-absorption phase.
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| 5. |
- Ghorbani, Ramin, 1981-, et al.
(author)
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Fitting of single-exhalation profiles using a pulmonary gas exchange model : application to carbon monoxide
- 2019
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In: Journal of Breath Research. - : Institute of Physics Publishing (IOPP). - 1752-7155 .- 1752-7163. ; 13:2
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Journal article (peer-reviewed)abstract
- Real-time breath gas analysis coupled to gas exchange modeling is emerging as promising strategy to enhance the information gained from breath tests. It is shown for exhaled breath carbon monoxide (eCO), a potential biomarker for oxidative stress and respiratory diseases, that a weighted, nonlinear least-squares fit of simulated to measured expirograms can be used to extract physiological parameters, such as airway and alveolar concentrations and diffusing capacities. Experimental CO exhalation profiles are acquired with high time-resolution and precision using mid-infrared tunable diode laser absorption spectroscopy and online breath sampling. A trumpet model with axial diffusion is employed to generate eCO profiles based on measured exhalation flow rates and volumes. The concept is demonstrated on two healthy non-smokers exhaling at a flow rate of 250 ml s−1 during normal breathing and at 120 ml s−1 after 10 s of breath-holding. The obtained gas exchange parameters of the two subjects are in a similar range, but clearly distinguishable. Over a series of twenty consecutive expirograms, the intra-individual variation in the alveolar parameters is less than 6%. After a 2 h exposure to 10 ± 2 ppm CO, end-tidal and alveolar CO concentrations are significantly increased (by factors of 2.7 and 4.9 for the two subjects) and the airway CO concentration is slightly higher, while the alveolar diffusing capacity is unchanged compared to before exposure. Using model simulations, it is found that a three-fold increase in maximum airway CO flux and a reduction in alveolar diffusing capacity by 60% lead to clearly distinguishable changes in the exhalation profile shape. This suggests that extended breath CO analysis has clinical relevance in assessing airway inflammation and chronic obstructive pulmonary disease. Moreover, the novel methodology contributes to the standardization of real-time breath gas analysis.
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| 6. |
- Ghorbani, Ramin, 1981-, et al.
(author)
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Impact of breath sampling on exhaled carbon monoxide
- 2020
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In: Journal of Breath Research. - : Institute of Physics Publishing (IOPP). - 1752-7155 .- 1752-7163. ; 14:4
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Journal article (peer-reviewed)abstract
- The influence of breath sampling on exhaled carbon monoxide (eCO) and related pulmonary gas exchange parameters is investigated in a study with 32 healthy non-smokers. Mid-infrared tunable diode laser absorption spectroscopy and well-controlled online sampling is used to precisely measure mouth- and nose-exhaled CO expirograms at exhalation flow rates (EFRs) of 250, 120 and 60 ml s−1, and for 10 s of breath-holding followed by exhalation at 120 ml s−1. A trumpet model with axial diffusion is employed to fit simulated exhalation profiles to the experimental expirograms, which provides equilibrium airway and alveolar CO concentrations and the average lung diffusing capacity in addition to end-tidal concentrations. For all breathing maneuvers, excellent agreement is found between mouth- and nose-exhaled end-tidal CO (ETCO), and the individual values for ETCO and alveolar diffusing capacity are consistent across maneuvers. The eCO parameters clearly show a dependence on EFR, where the lung diffusing capacity increases with EFR, while ETCO slightly decreases. End-tidal CO is largely independent of ambient air CO and alveolar diffusing capacity. While airway CO is slightly higher than, and correlates strongly with, ambient air CO, and there is a weak correlation with ETCO, the results point to negligible endogenous airway CO production in healthy subjects. An EFR of around 120 ml s−1 can be recommended for clinical eCO measurements. The employed method provides means to measure variations in endogenous CO, which can improve the interpretation of exhaled CO concentrations and the diagnostic value of eCO tests in clinical studies.Clinical trial registration number: 2017/306-31
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| 7. |
- Högman, Marieann
(author)
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Innovative exhaled breath analysis with old breathing manoeuvres-is there a problem or an advantage?
- 2017
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In: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 11:3
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Journal article (peer-reviewed)abstract
- As the field of exhaled breath research is expanding, the question that arises is can the old usual method of spirometry be used in all cases? The answer is yes for some analysation methods and definitely not for others: it all depends on the result you are looking for. Exhaled breath condensate collection can be accomplished with silent tidal breathing, but not in the analysation of the amount of exhaled particles, as they become very low during tidal breathing. There are gases that are exhalation flow dependent, e.g. nitric oxide, acetone and ethanol, that require a special breathing manoeuvre with flow control. Physiological changes of the lung, i.e. inhalation to total lung capacity or forced exhalation such as during spirometry, will affect the result of exhaled biomarkers. The standardisation of exhaled breath requires further development, and there are many aspects to consider.
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| 8. |
- Högman, Marieann
(author)
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Reference equations for exhaled nitric oxide-what is needed?
- 2024
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In: Journal of Breath Research. - : Institute of Physics (IOP). - 1752-7155 .- 1752-7163. ; 18:3
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Journal article (peer-reviewed)abstract
- Standardisation is the road to improvement! If we all measure exhaled nitric oxide (NO) the same way, we will be successful in having data to make reference questions. Many research groups have published their reference equation, but most differ considerably. About 25 years ago, using the flow of 50 ml s(-1) was recommended and not using a nose clip. When collecting data worldwide, we still see publications that do not indicate what flow was used and that nose clip was utilised. Three things are needed: the analysing method, a flow recording and a filled-in nitric oxide questionnaire. The analysing method is because the techniques have different sensitivity, response times and calibration. The flow of 50 ml s(-1) is on the steep part of the NO output curve; therefore, we need to record the flow to analyse repeated measurements or compare results. The NO questionnaire controls individual factors that may influence the NO measurements, i.e. food intake, smoking and upper airway infection. An important tool in following old and new disease treatments, at home or in health care, is exhaled biomarkers. If we follow the standardisation we have agreed upon, we will be able to have data to say what a high or a low exhaled NO value is.
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| 9. |
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| 10. |
- Jacinto, Tiago, et al.
(author)
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Differential effect of cigarette smoke exposure on exhaled nitric oxide and blood eosinophils in healthy and asthmatic individuals
- 2017
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In: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 11:3
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Journal article (peer-reviewed)abstract
- Background:Tobacco smoking affects both the fraction of exhaled nitric oxide (FeNO) and blood eosinophil (B-Eos) count, two clinically useful biomarkers in respiratory disease that represent local and systemic type-2 inflammation, respectively.Objective:We aimed to study the influence of objectively measured smoke exposure on FeNO and B-Eos in a large population of subjects with and without asthma.Methods:We utilized the US National Health and Nutrition Examination Surveys 2007-2012 and included 10 669 subjects aged 6-80 years: 9869 controls and 800 asthmatics. Controls were defined as having no respiratory disease, no hay fever in the past year, and B-Eos count ≤0.3 × 109 l−1. Asthma was defined as self-reported current asthma and at least one episode of wheezing or an asthma attack in the past year, but no emphysema or chronic bronchitis. Tobacco use was collected via questionnaires and serum cotinine was measured with mass spectrometry.Results:Increasing cotinine levels were associated with a progressive reduction in FeNO in both controls and asthmatics. FeNO remained significantly higher in asthmatics than controls except in the highest cotinine decile, equivalent to an average reported consumption of 13 cigarettes/day. B-Eos count increased with cotinine in controls, but was unchanging in asthmatics. Interestingly, B-Eos count was significantly higher in presently non-exposed (cotinine below detection limit) former smokers than never smokers.Conclusion:Smoke exposure decreases FeNO and increases B-Eos count. These effects should be considered in the development of normalized values and their interpretation in clinical practice. The persistence of elevated B-Eos in former smokers warrants further studies.
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