A breath sampling system assessing the influence of respiratory rate on exhaled breath composition

Abstract

This work presents a computerized system to monitor mouth pressure, tidal volume, exhaled airflow, respiration rate and end-tidal partial pressure of CO2 during breath collection. The system was used to investigate the effect of different respiratory rates on the volatile organic compounds (VOCs) concentrations in exhaled breath. For this purpose, VOCs with well-defined biochemical pathways and different chemical and physical properties were selected as biomarkers related to metabolism (acetone and isopropyl alcohol), cholesterol synthesis (isoprene) and intestinal microflora activity (ethanol). Mixed breath was collected from a nominally healthy volunteer in resting conditions by filling a Nalophan bag. The subject followed a regimented breathing pattern at different respiratory rates (10, 30 and 50 breaths per minute). Results highlight that ventilation pattern strongly influences the concentration of the selected compounds. The proposed system allows exhaled breath to be collected also in patients showing dyspnea such as in case of chronic heart failure, asthma and pulmonary diseases.

polyHWG: 3D Printed Substrate-Integrated Hollow Waveguides for Mid-Infrared Gas Sensing

“…28,29 However, not only pulmonary diseases directly affecting the airways, but in fact any disease eventually produces metabolic byproducts that reflect in an altered composition of the exhaled breath matrix, e.g., cardiovascular diseases. 30 Frequently, such diseases give rise to significantly elevated levels of various volatile organic compounds (VOC)e.g., isoprene and isopropyl alcohol 31  which may be detectable via MIR sensor technologies, in particular, if bright light sources such as tunable quantum cascade lasers (tQCLs) or interband cascade lasers (ICL) are used. 16,32−37 The polyHWGs presented herein are ideally suited for exhaled breath diagnostics in combination with broadband IR light sources (e.g., coupling to a FTIR spectrometer) or tQCLs, and may potentially be used as a consumable sampling interface when screening series of patients.…”

“…Carbon dioxide (CO 2 ) is a major metabolite providing direct information on vital functions, e.g., in intensive care scenarios. , Pulmonary diseases such as asthma, cystic fibrosis, and lung cancer are readily linked to selected molecular biomarkers present in exhaled breath including nitric oxide, hydrogen peroxide, etc. , However, not only pulmonary diseases directly affecting the airways, but in fact any disease eventually produces metabolic byproducts that reflect in an altered composition of the exhaled breath matrix, e.g., cardiovascular diseases . Frequently, such diseases give rise to significantly elevated levels of various volatile organic compounds (VOC)e.g., isoprene and isopropyl alcoholwhich may be detectable via MIR sensor technologies, in particular, if bright light sources such as tunable quantum cascade lasers (tQCLs) or interband cascade lasers (ICL) are used. ,− …”

A sampler prototype for the simultaneous collection of exhaled air and breath condensate

“…The use of the three T-piece connectors, commonly used in breathing systems and other respiratory management products, connected to a conical tube and a non-return valve produced a limited pressure drop that did not exceeded the back pressure of 100 Pa, which usually characterizes the common human respiratory devices [25]. Therefore, the prototype did not modified the normal inspiration-expiration maneuvers, limiting the possible variations of the breath composition due to the changes of breathing patterns [26]. In fact, during a 5-min self-paced breathing experiment (10 breaths per minute), real-time end-tidal pCO2 fluctuated randomly within a 10%, highlighting the absence of hyperventilation effect.…”

Sport in Town: The Smart Healthy ENV Project, a Pilot Study of Physical Activity with Multiparametric Monitoring

“…The significant decrease (i.e., by at least a factor of three) in breath isoprene levels after exercise may be due to the increase in both the respiratory rate and cardiac output. The increase in respiratory rate leads to a decrease in the tidal volume with a concomitant increase in the ventilation of the upper airway area [ 43 , 44 ]. This scenario affects compounds like isoprene that are mainly present in alveolar air.…”