Non-Invasive O-Toluidine Monitoring during Regional Anaesthesia with Prilocaine and Detection of Accidental Intravenous Injection in an Animal Model.

Regional anaesthesia is well established as a standard method in clinical practice. Currently, the local anaesthetics of amino-amide types such as prilocaine are frequently used. Despite routine use, complications due to overdose or accidental intravenous injection can arise.

Effects of COVID-19 protective face masks and wearing durations on respiratory haemodynamic physiology and exhaled breath constituents.

Background: While assumed to protect against coronavirus transmission, face masks may have effects on respiratory-haemodynamic parameters. Within this pilot study, we investigated immediate and progressive effects of FFP2 and surgical masks on exhaled breath constituents and physiological attributes in 30 adults at rest.

Methods: We continuously monitored exhaled breath profiles within mask space in older (age 60-80 years) and young to middle-aged (age 20-59 years) adults over the period of 15 and 30 min by high-resolution real-time mass-spectrometry.

Spatial mapping of VOC exhalation by means of bronchoscopic sampling.

Breath analysis holds promise for non-invasive in vivo monitoring of disease related processes. However, physiological parameters may considerably affect profiles of exhaled volatile organic substances (VOCs). Volatile substances can be released via alveoli, bronchial mucosa or from the upper airways.

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

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.

Safety and applicability of a pre-stage public access ventilator for trained laypersons: a proof of principle study.

Background: Contemporary resuscitation guidelines for basic life support recommend an immediate onset of cardiac compressions in case of cardiac arrest followed by rescue breaths. Effective ventilation is often omitted due to fear of doing harm and fear of infectious diseases. In order to improve ventilation a pre-stage of an automatic respirator was developed for use by laypersons.

Applied upper-airway resistance instantly affects breath components: a unique insight into pulmonary medicine.

Respiratory parameters such as flow or rate have complex effects on the exhalation of volatile substances and can hamper clinical interpretation of breath biomarkers. We have investigated the effects of progressively applied upper-airway resistances on the exhalation of volatile organic compounds (VOCs) in healthy humans. We performed real-time mass-spectrometric determination of breath volatiles in 50 subjects with parallel, non-invasive hemodynamic monitoring, breath-resolved spirometry and capnometry during controlled tidal breathing (12 breaths/min).

Oral or nasal breathing? Real-time effects of switching sampling route onto exhaled VOC concentrations.

There is a need for standardisation in sampling and analysis of breath volatile organic compounds (VOCs) in order to minimise ubiquitous confounding effects. Physiological factors may mask concentration changes induced by pathophysiological effects. In humans, unconscious switching of oral and nasal breathing can occur during breath sampling, which may affect VOC patterns.

Drug detection in breath: non-invasive assessment of illicit or pharmaceutical drugs.

Breath analysis not only holds great potential for the development of new non-invasive diagnostic methods, but also for the identification and follow up of drug levels in breath. This is of interest for both, forensic and medical science. On the one hand, the detection of drugs of abuse in exhaled breath-similar to the well-known breath alcohol tests-would be highly desirable as an alternative to blood or urine analysis in situations such as police controls for drugged driving.

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

Analysis of exhaled VOCs can provide information on physiology, metabolic processes, oxidative stress and lung diseases. In critically ill patients, VOC analysis may be used to gain complimentary information beyond global clinical parameters. This seems especially attractive in mechanically ventilated patients frequently suffering from impairment of gas exchange.

FEV manoeuvre induced changes in breath VOC compositions: an unconventional view on lung function tests.

Breath volatile organic compound (VOC) analysis can open a non-invasive window onto pathological and metabolic processes in the body. Decades of clinical breath-gas analysis have revealed that changes in exhaled VOC concentrations are important rather than disease specific biomarkers. As physiological parameters, such as respiratory rate or cardiac output, have profound effects on exhaled VOCs, here we investigated VOC exhalation under respiratory manoeuvres.

Instant effects of changing body positions on compositions of exhaled breath.

Concentrations of exhaled volatile organic compounds (VOCs) may depend not only on biochemical or pathologic processes but also on physiological parameters. As breath sampling may be done in different body positions, effects of the sampling position on exhaled VOC concentrations were investigated by means of real-time mass spectrometry. Breaths from 15 healthy volunteers were analyzed in real-time by PTR-ToF-MS-8000 during paced breathing (12/min) in a continuous side-stream mode.

Continuous real time breath gas monitoring in the clinical environment by proton-transfer-reaction-time-of-flight-mass spectrometry.

Analysis of volatile organic compounds (VOCs) in breath holds great promise for noninvasive diagnostic applications. However, concentrations of VOCs in breath may change quickly, and actual and previous uptakes of exogenous substances, especially in the clinical environment, represent crucial issues. We therefore adapted proton-transfer-reaction-time-of-flight-mass spectrometry for real time breath analysis in the clinical environment.

Drug detection in breath: effects of pulmonary blood flow and cardiac output on propofol exhalation.

Breath analysis could offer a non-invasive means of intravenous drug monitoring if robust correlations between drug concentrations in breath and blood can be established. In this study, propofol blood and breath concentrations were determined in an animal model under varying physiological conditions. Propofol concentrations in breath were determined by means of two independently calibrated analytical methods: continuous, real-time proton transfer reaction mass spectrometry (PTR-MS) and discontinuous solid-phase micro-extraction coupled with gas chromatography mass spectrometry (SPME-GC-MS).

Assessment of propofol concentrations in human breath and blood by means of HS-SPME-GC-MS.

Background: Breath analysis could offer a non-invasive means of drug monitoring if adequate analytical methods and robust correlations between drug concentrations in breath and blood can be established. We therefore applied headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) to assess breath and blood concentrations of the intravenous drug propofol in patients under anesthesia or sedation.

Methods: Arterial, central- and peripheral-venous blood and alveolar breath samples were drawn in parallel from 16 mechanically ventilated patients.