Monitoring of breath VOCs and electrical impedance tomography under pulmonary recruitment in mechanically ventilated patients

Brock, Beate; Kamysek, Svend; Silz, Josephine; Trefz, Phillip; Schubert, Jochen K.; Miekisch, Wolfram

doi:10.1088/1752-7163/aa53b2

Cited by 38 publications

(31 citation statements)

References 35 publications

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“…This is in accordance with the fact that ammonia exhalation is pH-dependent. Brock et al reported a 33% change of [NH 4 + ] / [NH 3 ], when pH is changed by only 0.1 [29]. …”

Section: Discussionmentioning

confidence: 99%

Exhaled volatile substances mirror clinical conditions in pediatric chronic kidney disease

et al. 2017

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Monitoring metabolic adaptation to chronic kidney disease (CKD) early in the time course of the disease is challenging. As a non-invasive technique, analysis of exhaled breath profiles is especially attractive in children. Up to now, no reports on breath profiles in this patient cohort are available. 116 pediatric subjects suffering from mild-to-moderate CKD (n = 48) or having a functional renal transplant KTx (n = 8) and healthy controls (n = 60) matched for age and sex were investigated. Non-invasive quantitative analysis of exhaled breath profiles by means of a highly sensitive online mass spectrometric technique (PTR-ToF) was used. CKD stage, the underlying renal disease (HUS; glomerular diseases; abnormalities of kidney and urinary tract or polycystic kidney disease) and the presence of a functional renal transplant were considered as classifiers. Exhaled volatile organic compound (VOC) patterns differed between CKD/ KTx patients and healthy children. Amounts of ammonia, ethanol, isoprene, pentanal and heptanal were higher in patients compared to healthy controls (556, 146, 70.5, 9.3, and 5.4 ppbV vs. 284, 82.4, 49.6, 5.30, and 2.78 ppbV). Methylamine concentrations were lower in the patient group (6.5 vs 10.1 ppbV). These concentration differences were most pronounced in HUS and kidney transplanted patients. When patients were grouped with respect to degree of renal failure these differences could still be detected. Ammonia accumulated already in CKD stage 1, whereas alterations of isoprene (linked to cholesterol metabolism), pentanal and heptanal (linked to oxidative stress) concentrations were detectable in the breath of patients with CKD stage 2 to 4. Only weak associations between serum creatinine and exhaled VOCs were noted. Non-invasive breath testing may help to understand basic mechanisms and metabolic adaptation accompanying progression of CKD. Our results support the current notion that metabolic adaptation occurs early during the time course of CKD.

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“…This is in accordance with the fact that ammonia exhalation is pH-dependent. Brock et al reported a 33% change of [NH 4 + ] / [NH 3 ], when pH is changed by only 0.1 [29]. …”

Section: Discussionmentioning

confidence: 99%

Exhaled volatile substances mirror clinical conditions in pediatric chronic kidney disease

et al. 2017

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“…preceded by a paced breathing) in all measured masses. Due to the analytical limitation of PTR-MS, changes in ammonia exhalation could not be measured with sufficient precision 44 . As all subjects were not exposed to exogenous compounds like acetonitrile (originated via smoking), benzene and toluene (derived from pre-exposure) 45 we could not draw any systemic relevance.…”

Section: Exhalation Of Endogenous Acetone Having Its Potential Origimentioning

confidence: 99%

Exhaled breath compositions under varying respiratory rhythms reflects ventilatory variations: translating breathomics towards respiratory medicine

Sukul¹,

Schubert²,

Zanaty³

et al. 2020

Sci Rep

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control of breathing is automatic and its regulation is keen to autonomic functions. therefore, involuntary and voluntary nervous regulation of breathing affects ventilatory variations, which has profound potential to address expanding challenges in contemporary pulmonology. nonetheless, the fundamental attributes of the aforementioned phenomena are rarely understood and/or investigated. implementation of unconventional approach like breathomics may leads to a better comprehension of those complexities in respiratory medicine. We applied breath-resolved spirometry and capnometry, non-invasive hemodynamic monitoring along with continuous trace analysis of exhaled Vocs (volatile organic compounds) by means of real-time mass-spectrometry in 25 young and healthy adult humans to investigate any possible mirroring of instant ventilatory variations by exhaled breath composition, under varying respiratory rhythms. Hemodynamics remained unaffected. Immediate changes in measured breath compositions and corresponding variations occurred when respiratory rhythms were switched between spontaneous (involuntary/unsynchronised) and/or paced (voluntary/synchronised) breathing. Such changes in most abundant, endogenous and bloodborne Vocs were closely related to the minute ventilation and end-tidal co 2 exhalation. Unprecedentedly, while preceded by a paced rhythm, spontaneous rhythms in both independent setups became reproducible with significantly (P-value ≤ 0.005) low intra-and inter-individual variation in measured parameters. We modelled breath-resolved ventilatory variations via alveolar isoprene exhalation, which were independently validated with unequivocal precision. Reproducibility i.e. attained via our method would be reliable for human breath sampling, concerning biomarker research. thus, we may realize the actual metabolic and pathophysiological expressions beyond the everlasting in vivo physiological noise. consequently, less pronounced changes are often misinterpreted as disease biomarker in cross-sectional studies. We have also provided novel information beyond conventional spirometry and capnometry. Upon clinical translations, our findings will have immense impact on pulmonology and breathomics as they have revealed a reproducible pattern of ventilatory variations and respiratory homeostasis in endogenous Voc exhalations. Human breath is a timeless source of in vivo metabolic, physiological/pathophysiological information, especially for lung conditions 1-3. Practice in pulmonology and breathomics have gradually encountered ubiquitous confounders; among which subject's own respiratory physiology associated variations (intra-/inter-individual) are crucial and evident 4-6. As breathomics suffered from insufficient fundamental knowledge on the effects of ventilatory variations, despite many efforts, pilot findings differed during independent validations. Thereby, breathomics

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“…Especially in diseased states, breath VOC concentrations may change quickly and abruptly. Hence, only real-time monitoring can provide complete and comprehensive information from breath VOC analysis [27][28][29]. PTR-ToF-MS with integration time of ≥ 200 ms enables breath-resolved continuous monitoring of breath volatiles.…”

Section: Discussionmentioning

confidence: 99%

Effects of modular ion-funnel technology onto analysis of breath VOCs by means of real-time mass spectrometry

et al. 2020

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Proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS) is a powerful tool for real-time monitoring of trace concentrations of volatile organic compounds (VOCs). The sensitivity of PTR-ToF-MS also depends on the ability to effectively focus and transmit ions from the relatively high-pressure drift tube (DT) to the low-pressure mass analyzer. In the present study, a modular ion-funnel (IF) is placed adjacent to the DT of a PTR-ToF-MS instrument to improve the ion-focusing. IF consists of a series of electrodes with gradually decreasing orifice diameters. Radio frequency (RF) voltage and direct current (DC) electric field are then applied to the electrodes to get the ions focused. We investigated the effect of the RF voltage and DC field on the sensitivity of a pattern of VOCs including hydrocarbons, alcohols, aldehydes, ketones, and aromatic compounds. In a proof-of-concept study, the instrument operating both as normal DT (DC-mode) and at optimal IF conditions (RF-mode) was applied for the breath analysis of 21 healthy human subjects. For the range of investigated VOCs, an improvement of one order of magnitude in sensitivity was observed in RF-mode compared with DC-mode. Limits of detection could be improved by a factor of 2–4 in RF-mode compared with DC-mode. Operating the instrument in RF-mode allowed the detection of more compounds in the exhaled air compared with DC-mode. Incorporation of the IF considerably improved the performance of PTR-ToF-MS allowing the real-time monitoring of a larger number of potential breath biomarkers.

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Monitoring of breath VOCs and electrical impedance tomography under pulmonary recruitment in mechanically ventilated patients

Cited by 38 publications

References 35 publications

Exhaled volatile substances mirror clinical conditions in pediatric chronic kidney disease

Exhaled volatile substances mirror clinical conditions in pediatric chronic kidney disease

Exhaled breath compositions under varying respiratory rhythms reflects ventilatory variations: translating breathomics towards respiratory medicine

Effects of modular ion-funnel technology onto analysis of breath VOCs by means of real-time mass spectrometry

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