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Gastrointestinal Disease
Published in John S. Axford, Chris A. O'Callaghan, Medicine for Finals and Beyond, 2023
Gareth Davies, Chris Black, Keeley Fairbrass
The general principles of breath tests are shown in Figure 10.17. Results need interpreting with caution as they can be affected by factors such as age, high-fibre meals and abnormal gastric emptying.
Paper 4
Published in Aalia Khan, Ramsey Jabbour, Almas Rehman, nMRCGP Applied Knowledge Test Study Guide, 2021
Aalia Khan, Ramsey Jabbour, Almas Rehman
Breath tests should not be done within 4 weeks of antibacterial treatment or 2 weeks of anti-secretory drugs. Both the breath and faecal antigen tests become negative after eradication unlike the serological test, therefore either the breath or faecal test should be used for diagnosis. Treatment with a proton pump inhibitor or ‘Test and Treat’ are two suggested interventions for un-investigated dyspepsia (NICE 2004). Also guidance suggests that breath test is the best investigation to check for eradication (SIGN).
Drug evaluation in children
Published in Evelyne Jacqz-Aigrain, Imti Choonara, Paediatric Clinical Pharmacology, 2021
Evelyne Jacqz-Aigrain, Imti Choonara
Non-invasive methods, such as the caffeine breath test, should be used if possible. The caffeine breath test has been used as a probe for CYP1A2 enzyme activity [5]. It has been used to study drug interactions (induction and inhibition) and also the effect of disease on drug metabolism [5]. It involves the use of a stable isotope of caffeine and the collection of breath samples for two hours after administration of the caffeine.
Exhaled metabolic markers and relevant dysregulated pathways of lung cancer: a pilot study
Published in Annals of Medicine, 2022
Yingchang Zou, Yanjie Hu, Zaile Jiang, Ying Chen, Yuan Zhou, Zhiyou Wang, Yu Wang, Guobao Jiang, Zhiguang Tan, Fangrong Hu
Exhaled breath test is a promising technique for large-scale screening of high-risk population of lung cancer for its convenience, low-cost and non-invasiveness. Therefore, detection of lung cancer through breath test has been thrown into a sharp focus. In 2019, Rudnicka et al. analyzed breath samples from 108 patients with lung cancer and 121 healthy volunteers with chromatography-mass spectrometry (GC-MS) [3]. Cross-validation of the obtained model has shown the sensitivity of 80% and specificity of 91.23%. In addition, Huang and Li used selected ion flow tube-mass spectrometry (SIFT-MS) technique to quantitatively analyze 116 volatile organic compounds (VOCs) in breath samples from 148 patients with histologically confirmed lung cancers and 168 healthy volunteers. A diagnostic model based on eXtreme Gradient Boosting (XGBoost) method was built, showing accuracy of 92% [4]. Although a series of research reported diagnostic models with highly sensitive and specific prediction, far exceeding the performance of currently available low-dose computed tomography (LDCT) detection, the clinical application of this technique is still challenging due to disease heterogeneity and lack of predictive molecular markers in exhaled breath.
Washout kinetics of ethanol from the airways following inhalation of ethanol vapors and use of mouthwash
Published in Clinical Toxicology, 2020
Lena Ernstgård, A. Pexaras, G. Johanson
This study shows that, in practice, inhalation of ethanol, even if carried out immediately before the breath alcohol test, does not result in an overestimate of the true BrAC value. In contrast, use of mouthwash might overestimate BrAC. People suspected of drunken driving, sometimes use mouthwash as an excuse when found positive in a breath alcohol test. However, in our study the BrAC fell below the Swedish statutory limit (0.10 mg/L) in less than 16 min in all 11 subjects. This suggests that the use of mouthwash does not explain a positive alcohol breath test as, in practice, it takes longer to get the car started, driving, be stopped by the police and carry out the breath test. In any case, a positive alcohol breath tests can easily be verified by repeating the test after 15 min or using a 15-min period of observation before testing, as already applied in many countries (e.g., California, Canada). Thus, after a positive breath test in Sweden, the driver is offered to breathe in an evidence instrument (Evidenzer, infrared technique) twice with 6–9 min in between or to take a venous blood sample. In California, a 15 min observation period is required before performing evidential roadside screening breath test [12]. Likewise, two breath tests are performed with 15 min in between for legally purposes in Canada [31].
Lung cancer breath tests
Published in Expert Review of Respiratory Medicine, 2019
While the prospective advantages of the introduction of breath tests into clinical practice seem tremendous, there are yet some challenges to overcome. This includes, but not confined to, confounding environmental conditions (e.g. temperature and humidity validations; exogenic contaminations, etc.) as well as other clinical factors (e.g. inhomogeneous test populations, genetic variations) – all may screen the high sensitivity and selectivity of the sensors’ technology. Additionally, there are substantial differences in methodology across the different studies that need to be taken into consideration. Taken all together, the implementation of breath tests as routine diagnostic and monitoring, especially in the digital era, is anticipated to significantly increase curability rates and lower the healthcare expenditure for societies.