| 1. |
- Lindberg, Lars, et al.
(författare)
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The advantages of standardizing exhaled breath-alcohol concentration to a reference respiratory gas—water vapor
- 2023
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Ingår i: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 17:1
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Forskningsöversikt (refereegranskat)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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| 2. |
- Ghorbani, Ramin, 1981-, et al.
(författare)
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Impact of breath sampling on exhaled carbon monoxide
- 2020
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Ingår i: Journal of Breath Research. - : Institute of Physics Publishing (IOPP). - 1752-7155 .- 1752-7163. ; 14:4
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Tidskriftsartikel (refereegranskat)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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| 3. |
- Högman, Marieann
(författare)
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Reference equations for exhaled nitric oxide-what is needed?
- 2024
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Ingår i: Journal of Breath Research. - : Institute of Physics (IOP). - 1752-7155 .- 1752-7163. ; 18:3
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Tidskriftsartikel (refereegranskat)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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| 4. |
- Jõgi, Nils Oskar, et al.
(författare)
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Device comparison study to measure nasal nitric oxide in relation to primary ciliary dyskinesia
- 2024
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Ingår i: Journal of Breath Research. - : Institute of Physics Publishing (IOPP). - 1752-7155 .- 1752-7163. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Primary ciliary dyskinesia (PCD) is a genetic respiratory disease characterized by chronic cough, recurrent respiratory infections, and rhinosinusitis. The measurement of nasal nitric oxide (nNO) against resistance has been suggested as a sensitive screening method. However, current recommendations argue for the use of expensive, chemiluminescence devices to measure nNO. This study aimed to compare nNO measurement using three different devices in distinguishing PCD patients from healthy controls and cystic fibrosis (CF) patients and to evaluate their diagnostic precision. The study included 16 controls, 16 PCD patients, and 12 CF patients matched for age and sex. nNO measurements were performed using a chemiluminescence device (Eco Medics CLD 88sp), and two devices based on electrochemical sensors (Medisoft FeNO+ and NIOX Vero) following standardized guidelines. Correlation estimation, Bland-Altman, ROC curve, and one-way ANOVA were used to assess device differences and diagnostic performance. Significantly lower nNO output values were observed in PCD and CF patients compared to controls during exhalation against resistance. The correlation analysis showed high agreement among the three devices. ROC curve analysis demonstrated 100% sensitivity and specificity at different cut-off values for all devices in distinguishing PCD patients from controls (optimal cut-offs: EcoMedics 73, Medisoft 92 and NIOX 87 (nl min-1)). Higher nNO output values were obtained with the Medisoft and NIOX devices as compared to the EcoMedics device, with a bias of-19 nl min-1(95% CI: -73-35) and -21 nl min-1(-73-31) accordingly. These findings indicate that all three tested devices can potentially serve as diagnostic tools for PCD if device specific cut-off values are used. This last-mentioned aspect warrants further studies and consideration in defining optimal cut-offs for individual device.
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| 5. |
- Ricciardolo, Fabio Luigi Massimo, et al.
(författare)
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Nitric oxide's physiologic effects and potential as a therapeutic agent against COVID-19
- 2021
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Ingår i: Journal of Breath Research. - : Institute of Physics Publishing (IOPP). - 1752-7155 .- 1752-7163. ; 15:1
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Forskningsöversikt (refereegranskat)abstract
- The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for COVID-19 pneumonia, a pandemic that precipitates huge pressures on the world's social and economic systems. Disease severity varies among individuals. SARS-CoV-2 infection can be associated with e.g. flu-like symptoms, dyspnoea, severe interstitial pneumonia, acute respiratory distress syndrome, multiorgan dysfunction, and generalized coagulopathy. Nitric oxide (NO), is a small signal molecule that impacts pleiotropic functions in human physiology, which can be involved in the significant effects of COVID-19 infection. NO is a neurotransmitter involved in the neural olfactory processes in the central nervous system, and some infected patients have reported anosmia as a symptom. Additionally, NO is a well-known vasodilator, important coagulation mediator, anti-microbial effector and inhibitor of SARS-CoV replication. Exhaled NO is strongly related to the type-2 inflammatory response found in asthma, which has been suggested to be protective against SARS-CoV-2 infection. Several reports indicate that the use of inhaled NO has been an effective therapy during this pandemic since the ventilation-perfusion ratio in COVID-19 patients improved afterwards and they did not require mechanical ventilation. The aim of this mini-review is to summarize relevant actions of NO that could be beneficial in the treatment of COVID-19.
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