Influence of respiratory variables on the on-line detection of exhaled trace gases by PTR-MS

Boshier, Piers R; Priest, Oliver; Hanna, George B.; Marczin, Nándor

doi:10.1136/thx.2011.161208

Cited by 27 publications

(34 citation statements)

References 4 publications

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“…Alternatively, the lack of exhalation flow dependency may result from back diffusion into the tissues allowing the gases to be washed away by the blood stream before axial diffusion can occur. The lack of exhalation flow dependency of acetone shown in a previous study [16] may be related to the use of much higher exhalation flow rates (15 l/min) which may have cancelled the effect of this variable. The significant effect produced by breath hold on the levels of acetone supports the theory that this gas may have an elevated airway uptake as opposed to ethanol which was not significantly affected by breath hold and therefore may have a higher central airway production/diffusion ration as suggested by its significant flow dependency and lack of reuptake.…”

Section: Discussionmentioning

confidence: 87%

“…Contrary to the measurement of exhaled NO which has been extensively investigated and standardised as described in joint ERS/ATS guidelines [24], only two preliminary studies have so far investigated the breathing parameters potentially affecting the levels of VOCs in the exhaled breath [16,17]. Notably, none of the so far published clinical studies controlled or investigated the effect of breathing parameters on VOC levels.…”

Section: Discussionmentioning

confidence: 99%

“…Contrary to the measurement of exhaled NO, which has been carefully standardised, the parameters potentially affecting VOCs levels in the breath have received little notice [16,17]. The lack of standardization of the previously published methods and the poor knowledge of the variables that may affect VOCs have hindered the use of these gases in research.…”

Section: Introductionmentioning

confidence: 99%

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Standardised exhaled breath collection for the measurement of exhaled volatile organic compounds by proton transfer reaction mass spectrometry

et al. 2013

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BackgroundExhaled breath volatile organic compound (VOC) analysis for airway disease monitoring is promising. However, contrary to nitric oxide the method for exhaled breath collection has not yet been standardized and the effects of expiratory flow and breath-hold have not been sufficiently studied. These manoeuvres may also reveal the origin of exhaled compounds.Methods15 healthy volunteers (34 ± 7 years) participated in the study. Subjects inhaled through their nose and exhaled immediately at two different flows (5 L/min and 10 L/min) into methylated polyethylene bags. In addition, the effect of a 20 s breath-hold following inhalation to total lung capacity was studied. The samples were analyzed for ethanol and acetone levels immediately using proton-transfer-reaction mass-spectrometer (PTR-MS, Logan Research, UK).ResultsEthanol levels were negatively affected by expiratory flow rate (232.70 ± 33.50 ppb vs. 202.30 ± 27.28 ppb at 5 L/min and 10 L/min, respectively, p < 0.05), but remained unchanged following the breath hold (242.50 ± 34.53 vs. 237.90 ± 35.86 ppb, without and with breath hold, respectively, p = 0.11). On the contrary, acetone levels were increased following breath hold (1.50 ± 0.18 ppm) compared to the baseline levels (1.38 ± 0.15 ppm), but were not affected by expiratory flow (1.40 ± 0.14 ppm vs. 1.49 ± 0.14 ppm, 5 L/min vs. 10 L/min, respectively, p = 0.14). The diet had no significant effects on the gasses levels which showed good inter and intra session reproducibility.ConclusionsExhalation parameters such as expiratory flow and breath-hold may affect VOC levels significantly; therefore standardisation of exhaled VOC measurements is mandatory. Our preliminary results suggest a different origin in the respiratory tract for these two gasses.

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Section: Discussionmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Standardised exhaled breath collection for the measurement of exhaled volatile organic compounds by proton transfer reaction mass spectrometry

et al. 2013

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“…Breath VOC sampling is a completely non‐invasive test with high acceptability among patients and clinicians. The authors envisage using exhaled breath testing as a triage investigation to establish the risk of pancreatic cancer in patients presenting with non‐specific symptoms to guide referral for CT. Another application is screening for high‐risk groups such as those with hereditary pancreatitis, familial pancreatic cancer, resent‐onset diabetes and intraductal papillary mucinous neoplasms.…”

Section: Discussionmentioning

confidence: 99%

Profile of exhaled-breath volatile organic compounds to diagnose pancreatic cancer

Markar

Brodie

Chin

et al. 2018

British Journal of Surgery

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Background: Pancreatic cancer has a very poor prognosis as most patients are diagnosed at an advanced stage when curative treatments are not possible. Breath volatile organic compounds (VOCs) have shown potential as novel biomarkers to detect cancer. The aim of the study was to quantify differences in exhaled breath VOCs of patients with pancreatic cancers compared with cohorts without cancer.Methods: Patients were recruited to an initial development cohort and a second validation cohort. The cancer group included patients with localized and metastatic cancers, whereas the control group included patients with benign pancreatic disease or normal pancreas. The reference test for comparison was radiological imaging using abdominal CT, ultrasound imaging or endoscopic ultrasonography, confirmed by histopathological examination as appropriate. Breath was collected from the development cohort with steel bags, and from the validation cohort using the ReCIVA™ system. Analysis was performed using gas chromatography-mass spectrometry.Results: A total of 68 patients were recruited to the development cohort (25 with cancer, 43 no cancer) and 64 to the validation cohort (32 with cancer, 32 no cancer). Of 66 VOCs identified, 12 were significantly different between groups in the development cohort on univariable analysis. Receiver operating characteristic (ROC) curve analysis using significant volatile compounds and the validation cohort produced an area under the curve of 0⋅736 (sensitivity 81 per cent, specificity 58 per cent) for differentiating cancer from no cancer, and 0⋅744 (sensitivity 70 per cent, specificity 74 per cent) for differentiating adenocarcinoma from no cancer. Conclusion:Breath VOCs may distinguish patients with pancreatic cancer from those without cancer.

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“…The exact origins of the VOC differentiating symptomatic and asymptomatic children are unknown but most likely result from a combination of airway obstruction [30], an increase in oxidative stress, changes in the microcirculation and the hosts immune response [31]. These compounds are likely to have both pulmonary and systemic origins.…”

Section: Discussionmentioning

confidence: 99%

Altered exhaled biomarker profiles in children during and after rhinovirus-induced wheeze

et al. 2014

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Preschool rhinovirus-induced wheeze is associated with an increased risk of asthma. In adult asthma, exhaled volatile organic compounds (VOC) are associated with inflammatory activity. We therefore hypothesised that acute preschool wheeze is accompanied by a differential profile of exhaled VOC, which is maintained after resolution of symptoms in those children with rhinovirus-induced wheeze.We included 178 children (mean±SD age 22±9 months) from the EUROPA cohort comparing asymptomatic and wheezing children during respiratory symptoms and after recovery. Naso-and oropharyngeal swabs were tested for rhinovirus by quantitative PCR. Breath was collected via a spacer and analysed using an electronic nose. Between-group discrimination was assessed by constructing a 1000-fold cross-validated receiver operating characteristic curve. Analyses were stratified by rhinovirus presence/absence.Wheezing children demonstrated a different VOC profile when compared with asymptomatic children ( p<0.001), regardless of the presence (area under the curve (AUC) 0.77, 95% CI 0.07) or absence (AUC 0.81, 95% CI 0.05) of rhinovirus. After symptomatic recovery, discriminative accuracy was maintained in children with rhinovirus-induced wheeze (AUC 0.84, 95% CI 0.06), whereas it dropped significantly in infants with non-rhinovirus-induced wheeze (AUC 0.67, 95% CI 0.06).Exhaled molecular profiles differ between preschool children with and without acute respiratory wheeze. This appears to be sustained in children with rhinovirus-induced wheeze after resolution of symptoms. Therefore, exhaled VOC may qualify as candidate biomarkers for early signs of asthma. @ERSpublications Children with rhinovirus-induced wheeze have altered exhaled biomarkers both during symptoms and after resolution

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Influence of respiratory variables on the on-line detection of exhaled trace gases by PTR-MS

Cited by 27 publications

References 4 publications

Standardised exhaled breath collection for the measurement of exhaled volatile organic compounds by proton transfer reaction mass spectrometry

Standardised exhaled breath collection for the measurement of exhaled volatile organic compounds by proton transfer reaction mass spectrometry

Profile of exhaled-breath volatile organic compounds to diagnose pancreatic cancer

Altered exhaled biomarker profiles in children during and after rhinovirus-induced wheeze

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