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Introduction Domiciliary oxygen therapy (DOT) is a treatment that requires a high level of cooperation from patients due to the time it takes every day. A high level of non-compliance has been determined among patients receiving DOT. The aim of our study was to assess the level of non-compliance and the influence of active tobacco consumption on compliance. Material and methods Patients were monitored in the home using direct and indirect methods, to assess both compliance and tobacco consumption. Results The level of non-compliance detected by indirect methods was 22.6%, and 66.3% by direct methods. Tobacco consumption determined by indirect methods was 5.8%–8%, depending on the method used, and 16.2% when CO in exhaled air ≥10 ppm was established as an indicator of tobacco use. The group of smokers complied with oxygen therapy for a significantly fewer number of hours per day (P Conclusions There is a high level of therapeutic non-compliance and a significant percentage of patients receiving DOT continue to smoke. Compliance must be monitored, and the correct use of DOT must be emphasized. Additional efforts should also be made to help smokers with DOT to stop smoking, since continued smoking impacts negatively on therapeutic non-compliance.

Nanosized Pt-loaded Fe2O3 nanocubes are prepared through, successively, a simple hydrothermal reaction, two-step annealing process and finally reduction with NaBH4 of H2PtCl4. The resultant Pt decorated Fe2O3 nanocubes, made up of Fe2O3 nanoplatelets, are hierarchical, hollow and porous, with an average edge length of 200–300 nm. The sensor based on Pt decorated Fe2O3 nanocomposites exhibits higher response (Rair/Rgas = 25.7) to 100 ppm of acetone gas at lower temperature (139 °C), with a short response-recovery time (3 s/22 s), compared with pure Fe2O3 nanocubes sensor. The Pt-Fe2O3 nanocomposite sensor shows excellent potential to act as a low cost, low temperature sensor for acetone gas, with high acetone selectivity under high humidity conditions and with the interference of other gases. Under various environmental conditions designed to mimic exhaled air, the sensor is able to detect ppb amounts of acetone, with high repeatability and stability, making it suitable for applications such as oral diabetic sensors. The attractive chemical and electronic sensitizations of partially oxidized Pt nanoparticles are responsible for the enhancement of acetone sensing performance. Based on the high acetone selectivity, high stability and fast dynamic response, the Pt enhanced Fe2O3 nanocubes sensor is an exceptionally suitable candidate for a low cost acetone sensor, and the proposed approach provides a route to develop gas sensors that can operate at low temperatures for a wide variety of applications.

In this paper, we report on the results of spectrofluorimetric study of new fluorescent sensor based on [Zn2L2] doped in ethyl cellulose. The sensor optical signal is based on the rapid fluorescence quenching in the presence of ethanol vapor. The ethanol vapor detection limit in a gas mixture by means of sensor based on [Zn2L2] doped in ethyl cellulose is 0.56 ppt. Being highly sensitive and selective to the ethanol vapor presence, instant in response and easy to use, the sensor may find an application for the monitoring of the content of ethanol vapor in the air at industrial and laboratory facilities. This sensor can serve as the basis of pocket gas analyzers for detecting ethanol in the exhaled air.

Background: One of the most relevant issue today is the diagnosis of COVID-19 at an early stage. A non-invasive approach to study exhaled air compositions can be used in solving the problem. Methods: The patients with COVID-19, with pneumonia unrelated to COVID-19, and healthy persons took part in the experiments. Samples of the exhaled air were analyzed by the gas analysis system - artificial neural network with a set of semiconductor gas sensors that characterizes the qualitative and quantitative composition of chemical compounds in the exhaled air. Findings: Analysis of the gas composition of the exhaled air of the patients with COVID-19 showed almost complete absence of molecular complex metabolic products (esters, alcohols, etc.). It is a characteristic sign of impairment of gas exchange at the level of alveolus-capillary and can be a diagnostic marker of the patients with COVID-19.The results of differential diagnosis in the classification of the healthy persons and the patients with disease at the level of sensitivity were 97.36 % and specificity - 98.63 %. Moreover, this system is able to differentiate cases of COVID-19 among the patients with inflammatory lung diseases not related to COVID-19 (sensitivity - 97.5 % and specificity - 92.11 %). Interpretation: Since the biochemical processes that occur with COVID-19 and community-acquired pneumonia are different, the gas sensors can provide detection of the characteristic features of the gas composition of exhaled air that are characteristic for an individual disease. The method is an effective tool in express diagnostics of COVID-19 and pneumonia, that may have a positive impact on clinical practice. Funding: None. Declaration of Interests: No potential conflicts of interest were disclosed. Ethics Approval Statement: The study was approved by the bioethical Committee of the Cancer Research Institute, Tomsk National Research Medical Center of the Russian Academy of Sciences (order on creation No. 57-r dated 23.12.2010).

Novel non-invasive methods for the diagnosis of malignancies should be effective for early diagnosis, reproducible, inexpensive, and independent from the human factor. Our aim was to establish the applicability of the non-invasive method, based on the analysis of air exhaled by patients who are at different stages of oropharyngeal, larynx and lung cancer. The diagnostic device includes semiconductor sensors capable of measuring the concentrations of gas components in exhaled air, with the high sensitivity of 1 ppm. The neural network uses signals from these sensors to perform classification and identify cancer patients. Prior to the diagnostic procedure of the non-invasive method, we clarified the extent and stage of the tumor according to current international standards and recommendations for the diagnosis of malignancies. The statistical dataset for neural network training and method validation included samples from 121 patients with the most common tumor localizations (lungs, oropharyngeal region and larynx). The largest number of cases (21 patients) were lung cancer, while the number of patients with oropharyngeal or laryngeal cancer varied from 1 to 9, depending on tumor localization (oropharyngeal, tongue, oral cavity, larynx and mucosa of the lower jaw). In the case of lung cancer, the parameters of the diagnostic device are determined as follows: sensitivity&mdash, 95.24%, specificity&mdash, 76.19%. For oropharyngeal cancer and laryngeal cancer, these parameters were 67.74% and 87.1%, respectively. This non-invasive method could lead to relevant medicinal findings and provide an opportunity for clinical utility and patient benefit upon early diagnosis of malignancies.

Introduction: Female smoker's present increased susceptibility to several diseases when compared to the opposite gender. However, there are no studies showing differences in nasal mucociliary transport behavior between male and female smokers. Objective: To compare the nasal mucociliary transportability in male and female smokers and non-smokers, taking into consideration age, anthropometric data, smoking load and pulmonary function. Methods: The analysis included 139 individuals (33 men and 37 women smokers and 32 men and 37 women non-smokers). All participants answered an initial interview to obtain personal data and smoking load. Anthropometric data and carbon monoxide in the exhaled air were assessed. Individuals also performed pulmonary function test and Saccharin Transit Time test. To compare saccharin transit time values between men and women, smokers and non-smokers, stratification of all independent variables was performed (sociodemographic, smoking and respiratory variables) into two categories: below and above the median values. Results: There was no difference between men and women, smokers and non-smokers, regarding nasal mucociliary transportability. Significant differences were only observed between non-smokers. Among those with less forced vital capacity values (

In this study, the handheld laser methane detector (LMD) was discussed as a tool for estimating the methane emissions of individual dairy cows by measuring the profiles of the exhaled air. Data obtained with the most recent generation of the device were compared with those of indirect open-circuit respiration chambers, which are commonly used to quantify methane emissions from ruminants. Data from two LaserMethane Mini-Green LMD units (Tokyo Gas Engineering Solutions) exhibited high agreement with those from four respiration chambers, two at the AgroVet-Strickhof, Eschikon, Lindau (Switzerland) and two at the Leibniz Institute for Farm Animal Biology (FBN) Dummerstorf (Germany). The results were determined using Pearson and concordance correlations and the Bland–Altman method. An inverse regression analysis was used to predict the amount of methane in the chambers from the LMD data. The two LMD units also agreed well with each other in the same respiration chamber and under farm conditions. Both the LMDs and chambers were suitable for detecting differences in mean methane concentrations in the spent air produced by dairy cows during different cow activities in the chamber (p

This study aimed to understand the volatile organic compound (VOC) emission levels and possible influencing factors in human exhaled breath via quantitative analysis. Using the experimental method developed previously, breath samples of 117 healthy human subjects were collected and analyzed. Concentration levels of 60 VOCs with the highest detection rates (DRs) were analyzed, and statistical results of emission rates of these VOCs are provided in a table for easy reference. In general, endogenous VOCs were found to have higher concentrations than exogenous VOCs. Furthermore, concentrations and emission rates of these VOCs were statistically compared for gender, different age groups, and smoking exposure types. The results of the univariate analysis showed that these three factors may yield a significant difference in concentration and emission of some, but not all, VOCs. The regression model showed that, for most VOCs, active/passive smoking and being male or of older age were most likely associated with higher emission levels. Age was emphasized to be a significant factor influencing VOC emissions through exhaled air in this study.

Exhaled breath analysis has attracted lots of researchers attention in the past decades due to its advantages such as its non-invasive property and the possibility of continuous monitoring. In addition, several volatile organic compounds in breath have been identified as biomarkers for some diseases. Particularly, studies have pointed out that concentration of isopropanol (IPA) in exhaled air might relate with certain illnesses such as liver disease, chronic obstructive pulmonary (COPD), and lung cancer. In this study, a highly sensitive and selective biochemical gas sensor (bio-sniffer) for the breath IPA concentration determination was constructed and optimized. This bio-sniffer measures the concentration of IPA according to the fluorescence intensity of oxidized nicotinamide adenine dinucleotide (NADH), which was produced by an enzymatic reaction of secondary alcohol dehydrogenase (S-ADH). The NADH detection system employed an UV-LED as the excitation light, and a highly sensitive photomultiplier tube (PMT) as a fluorescence intensity detector. A gas-sensing region was developed using an optical fiber probe equipped with a flow-cell and enzyme immobilized membrane, and connected to the NADH measurement system. The calibration range of the IPA bio-sniffer was confirmed from 1ppb to 9060ppb that was comparable to other IPA analysis methods. The results of the analysis of breath IPA concentration in healthy subjects using the bio-sniffer showed a mean concentration of 16.0ppb, which was similar to other studies. These results have demonstrated that this highly sensitive and selective bio-sniffer could be used to measure the IPA in exhaled air, and it is expected to apply for breath IPA research and investigation of biomarkers for clinical diagnosis.

It is well known that a considerable amount of radioiodine is exhaled after radioiodine therapy (RIT) leading to unwanted radiation exposure through inhalation for non-involved persons. This study focuses on the amount of exhalation in the breath-out air of RIT-patients and the dosimetric consequences. Furthermore, the correlation between radioiodine uptake and exhalation was investigated. The radioiodine species were collected in a filter system and quantified over time by measurements with a scintillation counter. The dosimetric implications were then studied for different exposure scenarios. Of the activity administered to the patient, approximately 10-3% (50-110 ppm) is exhaled. The radioiodine inhalation taking place following exhalation in the vicinity yields doses of up to 500 μSv (children, staying with the patient immediately after application and for the next 8 h). Three days after administration the doses are significantly reduced. This study lays emphasis on previous assumptions that exhalation depends on thyroid storage. Regardless of the type of thyroid disease, the predominant form exhaled is organic radioiodine. The amount of exhaled radioiodine is small but from the point of view of radiation protection, by no means negligible immediately after administration. Radiation doses received by incorporation of exhaled radioiodine can easily exceed 100 μSv soon after administration of radioiodine. Three days after RIT the radioactivity can still be measured in the exhaled air but even at maximum, the annual doses lie far below 10 μSv and are thus comparatively low.

The paper reports the design, construction, and calibration of the prototype of a spirometer based on electronic speckle interferometry (ESPI). The conventional ESPI setup is modified by incorporating a DNM (Diaphragm-Nozzle-Mouthpiece) module comprising a metallic diaphragm, regulated airflow channel, and a mouthpiece. The exhaled air after a deep breathe is channelled to the DNM module where the diaphragm gets deformed. From the circular fringe pattern obtained by subtracting the speckled images before and after deformation of the metallic diaphragm, the radius of curvature (R) due to deformation is calculated using the principle of Newton's rings. The value of R and peak expiratory flow rate (PEFR) from the standard spirometer reading are correlated. From the 640 observations spread over the range 100 - 500 L/min in the standard spirometer, an empirical relation is set in terms of R from the scatter plot. The ESPI spirometer (ESPIS) is validated by determining the value of R corresponding to a particular PEFR from the empirical relation and also from the standard spirometer. The PEFR calculated from ESPIS matches well with the standard spirometer reading, which suggests that the system designed and constructed can be used for biomedical applications for assessing lungs’ efficiency.

Patients with asthma exhale high concentrations of nitric oxide (NO), making the measurement of NO clinically important. Although we previously developed a 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl (PTIO) chip that relied on the reaction between NO gas and PTIO in the chip, the sensitivity and accuracy were insufficient for measuring NO in air exhaled by asthma patients. In this study, we focus on the conversion of NO to NO2 in the reaction with PTIO, and devise a new method to measure the converted NO2 using our previously developed NO2 analytical chip. NO is converted to NO2 in the PTIO chip and immediately released upon exposure to the atmosphere. This released NO2 is trapped on the adjacent NO2 analytical chip and reacts with diazo-coupling reagents to form an azo dye; a linear relationship was identified between the NO concentration and the change in absorbance at 525 nm due to production of the azo dye. The NO concentration could be measured in the 0−142 ppb range with a maximum error of ± 10 ppb at 142 ppb using the devised method, demonstrating sufficient sensitivity and accuracy for measuring NO in exhaled air. Furthermore, we successfully measured NO in the exhaled air of seven healthy adults, and detected ~19 ppb of NO, thus illustrating its feasibility for clinical use.

Maximum CO2 exposure requirements for building occupants are defined in present indoor climate standards. In occupied spaces CO2 is generated mainly by air exhaled by the occupants and part of the exhaled air with high CO2 concentration is re-inhaled before it is mixed with the surrounding air. Therefore the CO2 concentration measured in any location in the room (including in the exhaust air) is different from the CO2 concentration in the inhaled air. This paper presents an apparatus for measuring exposure to CO2. The apparatus is installed on a headset and equipped with a sampling tube located close to the mouth/nose and two pneumatic solenoid valves, and is controlled such that gas samples are taken only during inspiration. Gas sampling is synchronized with the inspiration period of the breathing cycle. The proposed system allows one to determine CO2 exposure more accurately than with the methods currently in use.

A procedure based on the use of ion mobility spectrometry (IMS), after liquid-liquid microextraction (LLME), has been successfully employed for the determination of passive exposure to nicotine from cigarette and e-cigarette smoking. Nicotine has been determined in exhaled breath and oral fluids of both, active and passive smokers. The aforementioned studies, made in closed environments, evidenced that the exhaled breath after conventional blend cigarette smoke provides nicotine levels of the order of 220 ng per puff, in the case of experienced smokers, being exhaled only 32 ng in the case of e-cigarettes. On the other hand, the nicotine amount in oral fluids of passive vapers was between 8 and 14 µg L(-1) lower than the average value of 38±14 µg L(-1) found for passive smokers of rolling tobacco and clearly lower than the 79±36 µg L(-1) obtained from passive smokers of classical yellow blend. This study was also placed in the frame of the verification of the e-cigarettes composition.

Purpose Bronchiolitis obliterans syndrome (BOS) as a form of chronic lung allograft dysfunction is a limiting factor to the survival of lung transplant recipients. Detection and monitoring of chronic rejection is hampered by a lack of clinically available markers. Particles in exhaled air (PExA) is proposed as a noninvasive means of potentially identifying and observing BOS patients. This pilot study aims to capture the range of exhaled particles expected in human samples and identify possible candidate markers. Methods The PExA device collects exhaled air using a two-way valve that allows subjects to inhale filtered air and exhale air into a reservoir from which an optical particle counter counts and sizes entering particles. Particles are collected according to their inertia and those above a threshold impact onto a plate, collecting onto a membrane of polytetrafluoroethylene. Total accumulated mass can be measured by the PExA device. Samples were obtained from two healthy subjects (1 combined 600 ng sample and 200 ng from each) and from five patients with lung pathology (1 grouped sample of 600 ng from three patients and 200 ng samples from two unique patients). The samples were analyzed via liquid chromatography-mass spectrometry on an Orbitrap Fusion Lumos mass spectrometer coupled to an easy-nLC1200 liquid chromatography system. Results The fifty most abundant proteins identified by mass spectrometry represented a breadth of biological function and a variety of localizations. Ten could be traced to immunological system processes and included a number of immunoglobulin constant regions. Sixteen of these most abundant proteins could be found in the extracellular region. A number are components of the plasma, including serotransferrin and annexin proteins. Fifteen proteins were found in greater abundance in the healthy subjects compared to patients while two (haptoglobin and gasdermin-A) were notable for a lower abundance in the patients. Conclusion The PExA device presents as a novel method for non-invasive analysis of lung transplant patients with the potential to monitor developing chronic rejection. This pilot study characterizes the range of proteins identified from samples across subjects and serves as a basis for the exploration of markers in chronic rejection patients. This work establishes a method for the ongoing effort to use PExA to identify and monitor BOS in lung transplant recipients.

Vaping is promoted as a healthier alternative to smoking over the recent years, and e-cigarette (EC) users are considered to affect air quality (and thus contribute to passive smoking) much less than tobacco cigarette (TC) smokers. Here we test this hypothesis, by comparing measurements of the size distributions of particles and the levels of Volatile Organic Compounds (VOCs) exhaled by both EC and TC users. A total of 26 individuals (16 EC users and 10 TC users) provided exhaled air samples that were analyzed using the same protocol. Our measurements show that the particle number concentration emitted by both EC and TC users are comparable, but the size distributions of the particles emitted by the former exhibit significantly higher variability compared to those from the latter. The burden of the VOCs was much higher in the exhaled air of TC smokers compared to that of EC users. Although some of the VOCs measured in the exhaled air of EC users were expected, as they are used directly in the e-liquids, the collected mixtures were highly variable (i.e., varying significantly from case to case) with only 8 compounds being common among all individuals participating in the study. In contrast, we identified 65 compounds among the TC smokers that were common among the participants. Toxic compounds (e.g., benzene, acetaldehyde, toluene, xylenes, styrene, phenol, naphthalene, etc.) were also present in the exhaled air of EC users. The high variabilities observed in the size distributions of the exhaled particles and the levels of VOCs from different EC users (i.e., due to different devices, operational settings and liquids) warrants for further research in order to fully understand the main- and side-stream effects of EC use in the human micro-environment. Despite that, the high particle emissions and the presence, even at trace levels, of toxic VOCs in the exhaled air of EC users that are reported in this study, suggests that ECs should not be considered as harmless substitutes of TCs.

Nitric oxide (NO) is a gaseotransmitter, which is involved in many signaling processes in health and disease. Three enzymes generate NO from L-arginine, with citrulline formed as a by-product: neuronal NO synthase (nNOS or NOS1), endothelial NOS (eNOS or NOS3) and inducible NOS (iNOS or NOS2). NO is a ligand of soluble guanylyl cyclase (sGC), an intracellular heterodimer enzyme that catalyzes the con- version of guanosine triphosphate (GTP) to cyclic GMP (cGMP). cGMP further activates protein kinase G that eventually reduces the smooth muscle tone in bronchi or vessels. Phosphodiesterase 5 (PDE5) de- grades cGMP to GMP. However, NO reacts with superoxide anion (O � ), leading to formation of the pro- inflammatory molecule peroxynitrite. Under physiological conditions, NO plays a homeostatic bronchoprotective role in healthy subjects. In obstructive airway diseases, NO can be beneficial by its bronchodilating effect, but could also be detrimental by the formation of peroxynitrite. Since asthma and COPD are associated with increased levels of exhaled NO, chronic inflammation and increased airway smooth muscle tone, the NO/sGC/cGMP pathway could be involved in these highly prevalent obstructive airway diseases. Here we review the involvement of NO, NO synthases, guanylyl cyclases, cGMP and phophodiesterase-5 in asthma and COPD and potential therapeutic approaches to modulate this pathway.

Asthma is a chronic condition characterized by ongoing inflammation of the airways. Common asthma symptoms include shortness of breath that worsens with activity, wheezing, and cough. The flow of exhaled air from the lungs may be restricted due to inflammation from excess mucous. The peak expiratory flow rate (PEFR) is a test that measures how fast a person can exhale. This test checks lung functioning, and is often used by patients who have asthma. For the PEFR test to be useful, the patient must keep continuous records of his or her flow rate. These patterns can help individuals prevent their symptoms from worsening before a full-blown asthma attack, for example. Individuals will know when they need to adjust their environment or medication, or make an appointment with the doctor.

Analyses of exhaled air by means of electronic noses offer a large diagnostic potential. Such analyses are non-invasive; samples can also be easily obtained from severely ill patients and repeated within short intervals. Lung cancer is the most deadly malignant tumor worldwide, and monitoring of lung cancer progression is of great importance and may help to decide best therapy. In this report, twenty-two patients with diagnosed lung cancer and ten healthy volunteers were studied using breath samples collected several times at certain intervals and analysed by an electronic nose. The samples were divided into three sub-groups; group d for survivor less than one year, group s for survivor more than a year and group h for the healthy volunteers. Prediction models based on partial least square and artificial neural nets could not classify the collected groups d, s and h, but separated well group d from group h. Using artificial neural net, group d could be separated from group s. Excellent predictions and stable models of survival day for group d were obtained, both based on partial least square and artificial neural nets, with correlation coefficients 0.981 and 0.985, respectively. Finally, the importance of consecutive measurements was shown.

Exhaled breath contains thousands of volatile organic compounds (VOCs) of which the composition varies depending on status of the individual and the environment. Different metabolic processes within the body produce volatile substances that are released into the blood. When the blood reaches the lungs the products are released into lung tissue and airways. Also, chronic inflammation and/or oxidative stress can result in the excretion of volatile compounds that generate unique VOC patterns. Therefore, measuring the presence of VOCs in exhaled air (breathomics), for clinical diagnosis and monitoring purposes has gained increased interest over the last years. This paper describes one methodology based on gas chromatography (GC) and deep ultraviolet (DUV) spectroscopy. Spectra of compounds found in exhaled breath are presented.

Nitric oxide (NO) has beneficial effects on cardiovascular and immune health. Stress and depression have been linked to a reduction in serum NO. In this study, we examined the effect of academic exam stress on the fraction of NO in exhaled air (FeNO) and spirometric lung function in 41 healthy college students. Participants completed assessments at mid-semester as well as in the early and late phase of an academic exam period. Negative affect, depressive mood, and salivary cortisol were elevated during exams, whereas FeNO and lung function decreased. Higher depressive mood was associated with lower FeNO, whereas higher negative affect was associated higher FeNO across time. These findings provide initial evidence that depression and prolonged stress can alter FeNO and lung function in healthy individuals, which could have adverse consequences for cardiovascular, airway, and immune health.

Finding a non-invasive, painless and simple screening method for early detection of cancer is a desirable goal. There is evidence that volatile organic compounds (VOCs) detectable in exhaled air and producing specific breath odor could be taken into consideration as possible cancer markers. Chemical analysis of VOCs in the breath that utilizes gas chromatography-mass spectrometry or an array of specific sensors (an electronic nose) could be useful for cancer screening. Preliminary reports show that canines, due to their extraordinary sense of smell and ability to perform well with operant conditioning, could also be used in the future as biological screeners for different forms of cancer. However, the question remains open whether specific VOCs or breath odors appear at very early (sub-clinical) stages of cancer disease or only at advanced stages of the disease during tumor decomposition.

Highlights ► Coughing velocity was found to be 15.3 m/s for male and 10.6 m/s for female. ► The angle of coughed air was around 38° for male and 32° for female. ► Height of test subject and his/her cough speed was linearly correlated., Increasing concerns about the spread of airborne pathogens such as severe acute respiratory syndrome (SARS) and novel swine-origin influenza A (H1N1) have attracted public attention to bioaerosols and protection against them. The airborne pathogens are likely to be expelled from coughing or speaking, so the physical data of the exhaled particles plays a key role in analyzing the pathway of airborne viruses. The objective of this study was to analyze the initial velocity and the angle of the exhaled airflow from coughing and speaking of 17 males and 9 females using Particle Image Velocimetry (PIV) and acrylic indoor chamber. The results showed that the average initial coughing velocity was 15.3 m/s for the males and 10.6 m/s for the females, while the average initial speaking velocity was 4.07 m/s and 2.31 m/s respectively. The angle of the exhaled air from coughing was around 38° for the males and 32° for the females, while that of the exhaled air from speaking was around 49° and 78° respectively. Also, the linear relation between the tested subject’s height and their coughing and speaking velocity was shown in this study.

SummaryBackgroundThe fraction of nitric oxide in exhaled air (FeNO) is used in asthma diagnosis and management. Smoking reduces FeNO and 20–35% of asthmatics are smoking. However no guidelines exist on the diagnostic value of FeNO in smokers. Therefore we assessed the value of FeNO to diagnose asthma in a population of subjects with asthma-like symptoms and different smoking habits.MethodsMeasurements of FeNO, lung function, bronchial responsiveness and allergy testing were performed in 282 subjects (108 never-, 62 ex- and 112 current smokers) aged 14–44 years, with symptoms suggestive of asthma. These subjects were a subset of subjects reporting respiratory symptoms (n = 686) in a random population sample (n = 10,400).ResultsA diagnosis of asthma was given to 96 of the 282 subjects. Subjects with asthma had higher FeNO levels than subjects with non-specific asthma symptoms in all three smoking strata (p

Summary In this study we test the hypothesis that endogenous particles in exhaled air (PEx), non-invasively sampled from lower airways, are well suited for the analysis of respiratory tract lining fluid (RTLF) proteins, i.e., surfactant protein A (SP-A) and albumin. Ten healthy volunteers were included in the study and participated in two sampling sessions. Blood, exhaled breath condensate (EBC) and PEx were collected at each session. 100 L of breath were collected for each exhaled sample. Serum and exhaled samples were analyzed for SP-A using an in-house ELISA. Albumin was analyzed in exhaled samples using a commercial ELISA kit. SP-A detection rates were 100%, 21%, and 89% for PEx, EBC and serum, respectively. Albumin was detected in PEx, but not in EBC. SP-A measurements in PEx showed good repeatability with an intra-individual coefficient of variation of 13%. Both SP-A and albumin showed significant correlation to mass of PEx ( r s = 0.93, p r s = 0.86, p = 0.003, respectively). Sampling and analysis of PEx is a valid non-invasive method to monitor RTLF proteins sampled from the lower respiratory tract, as demonstrated here by example of SP-A and albumin analysis.

A method for qualitative and quantitative the determination of concentrations volatile organic compounds (VOCs) in human breath samples using solid phase microextraction (SPME) and gas chromatography-time of flight-mass spectrometry (GC-TOF/MS) has been carried out. They are employed for the preconcentration, separation and analysis of biological samples. The technique to rapid determination compounds present in human air, at the level of parts per billion (ppb) is applied. This method was optimized and evaluated. It showed linear correlations ranging from 0.83 to 234.05 ppb, limit of detection in the range of 0.31 to 0.75 ppb and precision, expressed as the RSD, was less then 10.00%. The unique combination of statistical methods allowed reduce the number of compounds to significant ones only and indicate the potential way to find the biomarkers of the lung cancer. Presented an analytical and statistical methods for detection composition of exhaled air could be applied as a potential non-intrusive tool for screening of lung cancer.

Exhaled air of individual cattle infected experimentally with foot-and-mouth disease virus (FMDV) was sampled to assess the feasibility of a rapid, non-invasive general screening approach for identifying sources of FMDV infection. The air sampler used was a handheld prototype device employing electrostatic particle capture in a microchip chamber of 10-15 μL and was shown to effectively capture a high percentage of airborne microorganisms. The particles were eluted subsequently from the chip chamber and subjected to real-time RT-PCR. Sampling exhaled air for as little as 1 min allowed the detection of FMDV in cattle infected experimentally. Detection in exhaled air from individual cattle was compared to FMDV detection in serum and saliva for 3 different strains of FMDV (O1/Manisa/69, C/Oberbayern/FRG/1960 and SAT1/Zimbawe/1989). Detection of FMDV in exhaled air was possible for all strains of FMDV used for experimental infection but the period that detection was possible varied among the strains. Detection in exhaled air generally peaked on day 2-4 post infection. The perspectives of monitoring for FMDV in the breath of infected cattle are discussed in the context of real-time epidemiological contingencies.

The nature of blood aerosols produced in physiological studies of an upright subject expiring small volumes through straws, spitting and mouthing sounds, and a semi-prone subject spitting through a bloody mouth or snorting through a single nasal orifice and by a simplified physical model of the respiratory system were investigated. Each manoeuvre produced many hundreds of droplets of a range of size, the vast majority being less than 1 mm diameter. Droplets under 1 mm dia. travelled over 1 m – much further than could be expected if their flight was ballistic, like that of impact spatter. Respired blood aerosol properties are explained in terms of established mechanics of airflow shear induced aerosol production and the fluid mechanics of exhaled air movement.

Background We aimed to measure propofol concentrations in exhaled air with an ion mobility spectrometer coupled to a multicapillary column for pre-separation (MCC–IMS). In addition, we aimed to compare the values of these measurements with serum propofol concentrations, as determined by gas chromatography–mass spectrometry (GC–MS). Methods Thirteen patients, ASA I or II, undergoing elective ENT surgery were studied. Anaesthesia was induced with propofol 2.1 (0.7) mg kg−1, rocuronium 0.5 (0.1) mg kg−1, and remifentanil 0.5 µg kg−1 min−1. After tracheal intubation, anaesthesia was maintained with a continuous infusion of propofol 3.9 (1.8) mg kg−1 h−1 and remifentanil 0.5 µg kg−1 min−1. Simultaneously, a venous blood sample was obtained. Propofol concentrations in serum were determined by GC–MS and compared with the height of the respective propofol signals achieved by MCC–IMS. Results Twenty-four pairs of samples were obtained. The comparison of propofol concentrations in exhaled air and serum presented a bias of −10.5% and a precision of ± 12.3%. With these values, the 95% limits of agreement were 14.1% and −35.1%. Conclusions MCC–IMS may be a suitable method to determine propofol concentrations in exhaled air, and may be used to predict propofol concentrations in serum.

Analysis of exhaled air leads to the development of fast accurate and non-invasive diagnostics. A comprehensive analysis of the entire range of volatile organic compounds (VOCs) in exhaled air samples will enable the identification of VOCs unique for certain patient groups. This study demonstrates proof of principle of our developed method tested on a smoking/non-smoking study population. Thermal desorption and gas chromatography coupled to time-of-flight mass spectrometry were used to analyse exhaled air samples. The VOC profiles obtained from each individual were combined into one final database based on similarity of mass spectra and retention indexes (RI), which offers the possibility for a reliable selection of compounds of interest. As proof of principle we correctly classified all subjects from population of smoking (N=11) and non-smoking (N=11) based on the VOC profiles available in their exhaled air. Support vector machine (SVM) analysis identified 4 VOCs as biomarkers of recent exposure to cigarette smoke: 2,5-dimethyl hexane, dodecane, 2,5-dimethylfuran and 2-methylfuran. This approach contributes to future development of fast, accurate and non-invasive diagnostics of inflammatory diseases including pulmonary diseases.

Respiratory water loss in Starlings (Sturnus vulgaris) at rest and during flight at ambient temperatures (T-amb) between 6 and 25 degrees C was calculated from respiratory airflow and exhaled air temperature. At rest, breathing frequency f(1.4 +/- 0.3 Hz) and tidal volume V-t (1.9 +/- 0.4 ml) were independent of T-amb but negatively correlated with each other. Mean ventilation at rest was 156 +/- 28 ml min(-1) at all T-amb. Exhaled air temperature (T-exh) at rest increased with T-amb (T-exh=0.92 center dot T-amb+12.45). Respiratory water loss at rest averaged 0.18 +/- 0.09 ml h(-1) irrespective of T-amb. In flying Starlings f was 4.0 +/- 0.4 Hz and independent of T-amb. V-t during flight averaged 3.6 +/- 0.4 ml and increased with T-amb (V-t=0.06 center dot T-amb+2.83) as, correspondingly, did ventilation. T-exh during flight increased with T-amb (T-exh=0.85 center dot T-amb+17.29). Respiratory water loss during flight (average REWLf=0.74 +/- 0.22 ml h(-1)) was significantly higher than at rest and increased with T-amb. Our measurements suggest that respiratory evaporation accounts for most water loss in flying Starlings and increases more than cutaneous evaporation with rising ambient temperature. (c) 2006 Elsevier Inc. All rights reserved.

The analysis of volatile organic compounds (VOC) in the human breath has attracted a considerable amount of clinical and scientific interest during the last decade. In our study, we turned our attention to gender and age specific differences of exhaled volatile compounds, particularly on isoprene which is one of the most abundant organic molecules found in human exhaled air. A total of 126 test persons were enrolled in the study: 66 females and 60 males. Moreover, the participants were classified into six groups with regard to their age. In a standardized setting all of them had to exhale the endexpiratory breath into a sample bag. The volatile compounds at m/z values from 21 to 229 were analyzed by using proton-transfer-reaction-mass-spectrometry. Isoprene (at m/z 69) was found to be highly significantly (p

The N(2) slope is an index of inhomogeneous distribution of ventilation and has been suggested to be suited for early testing of chronic obstructive pulmonary disease (COPD) in smokers. The aim of the present study was to examine the association between the fraction of exhaled nitric oxide (FENO) and the N(2) slope in a random population of smoking and non-smoking men. Altogether 57 subjects were included in the study, 24 never-smokers, seven ex-smokers and 26 current smokers. Subjects were examined twice, in 1995 when they regarded themselves as healthy, and in a follow-up in 2001. Spirometry, N(2) slope and high-resolution computed tomography (HRCT) were performed in 1995 while the follow-up examination included also measurement of FENO. The FENO value was significantly lower and the N(2) slope higher in current smokers. In smokers but not in never- or ex-smokers FENO was correlated to the difference in N(2) slope between 1995 and 2001 (r(s)=0.49, P=0.01). We analysed the data by multiple linear regression adjusted for smoking, mild respiratory symptoms and inhaled steroids. There were significant associations between FENO and the N(2) slope both in 1995 and in 2001. The strongest association was found to exist with the change in N(2) slope during these years. Sixteen of the subjects could be classified as having COPD, six with mild and ten with moderate COPD. There was a trend for an increase in N(2) slope with increased severity of COPD; among subjects with no COPD the N(2) slope in 2001 was 2.3% N(2)/L, and those with mild and moderate COPD had 2.5% N(2)/L and 3.9% N(2)/L, respectively (P=0.0004). No such trend was seen for FENO (17.8, 15.5 and 20.3 parts per billion (ppb), respectively, P=0.8). The results show that FENO is associated with the N(2) slope, indicating that FENO reflects inflammatory changes in the peripheral airways of both non-smoking and smoking subjects.

Biomonitoring is the study of the presence and concentration of chemicals in humans usually by the measurement of blood, urine or breath (exhaled air). Properly conducted, these data provide a picture of the amount of a chemical or agent actually absorbed into the body for a specific period of time. This review provides a history of biomonitoring, as well as the limitations and potential benefits of these studies. Examples of the proper and possibly improper use of biomonitoring and the impact made on our society are provided. Reasons for having comprehensive national biomonitoring programs are summarized, along with the societal benefits and risks. A brief discussion of the history of the NHANES program and select results from the 2005 Report are presented. By 2010, it has been predicted that the Centers for Disease Control (CDC) will be monitoring nearly 1000 chemicals in persons from all regions of the nation. The measurement of chemicals and biomarkers has revolutionized the field of exposure assessment. Overall, we recommend an approach of careful interpretation, understanding that the data obtained are useful for establishing baseline information about exposure, rather than equating detection with risk. We present suggestions for contextualizing biomonitoring results in order to provide the public with the tools to distinguish genuine health risks from trivial ones.

Summary Currently no published data are available concerning the comparability of different types of NO analysers, making inter-laboratory comparisons difficult. In two sets of experiments we compared 4 and 5 NO analysers, respectively, from 3 different manufacturers using different calibration regimes: calibration with (1) a separate recommended calibration gas for each analyser, (2) a single low concentration for all (394 ppb), and (3) a single high concentration (12.8 ppm). We measured three subjects with known low (L), moderate (M) and high (H) bronchial exhaled nitric oxide concentrations as well as standard gases (SG). In the first set of experiments, calibration regime 1 resulted in the largest differences between analysers (coefficient of variation (CV) for L, M, H, SG: 0.42, 0.22, 0.20, 0.14). The lowest CV between analysers was observed after calibration 2 (0.34, 0.19, 0.12, 0.02). Very similar results were obtained in the second set of comparisons. Thus, differences between analysers existed, but were mainly due to differences in recommended calibration gases/procedures. Only a small part was explainable by deviations from target flow. These differences need to be taken into account when comparing data between laboratories or replacing the calibration gas of an analyser, as well as for the establishment and interpretation of normal values.

Percutancous absorption of m-xylene (XYL) was determined in volunteers exposed to 29.4 mug cm(-1) XYL vapour on the forearm and hand for 20, 45, 120 and 180 min. The internal exposure was assessed by measuring the concentration of XYL in exhaled air. The systemic kinetics were determined using a reference exposure by inhalation. The dermal permeation rate and the cumulative absorption of XYL as a function of time were calculated using mathematical deconvolution. From these relationships, the average flux into the skin throughout the exposure (J(skin), average) and the maximal flux into the blood (J(bood.max)) were derived. Both fluxes were dependent on the duration of exposure, approaching each other at longer exposure durations. The values of J(skin.average), adjusted to a concentration of 1 mug cm(-3), were 0.091 mug cm(-2) h(-1) during 20-min exposure falling to 0.072, 0.066 and 0.061 mug cm(-2) h(-1) for 45, 120 and 180min, respectively. The values of J(blood, max) showed an opposite trend, gradually increasing from 0.034 mug cm(-2) h(-1) at an exposure duration of 20 min to 0.042, 0.059 and 0.063 mug cm(-2) h(-1) for 45, 120 and 180 min of exposure durations, respectively. (C) 2004 Elsevier Ireland Ltd. All rights reserved

Background: Bacterial pneumonia involves influx of activated phagocytes into distal airways. These cells release oxidants including H2O2, that may be exhaled or induce peroxidative damage to lung tissues with formation of thiobarbituric reactive substances (TBARs).Study objectives: To determine whether concentrations of H2O2 and TBARs in exhaled breath condensate (EBC) is elevated and correlate with systemic response to pneumonia during 10 days of hospital treatment.Design: The concentration of H2O2 and TBARs was measured in EBC of 43 inpatients with community acquired pneumonia (CAP) and 20 healthy never smoked subjects over 10 days and were accompanied by monitoring of WBC count, serum concentration of C-reactive protein (CRP) and peroxyl radical-trapping capacity.Results: Patients with CAP exhaled 4.6-, 3.7-, 3.9-, 3.3-times more H2O2 than healthy controls at 1st, 3rd, 5th and 10th day of treatment (P

We investigated the sensitivity and reproducibility of a test procedure for measuring hydrogen peroxide (H 2 O 2 ) in exhaled breath condensate and the effect of storage of the condensate on the H 2 O 2 concentration, and compared the results to previous studies. Twenty stable COPD patients breathed into our collecting device twice for a period of 10 min. The total exhaled air volume (EAV) and condensate volume were measured both times and the H 2 O 2 concentration of the condensate was determined fluorimetrically. The concentration was measured again after freezing the reaction product at −70°C for a period of 10, 20 and 40 days. We collected 2–5 ml condensate in 10 min. The EAV and condensate volumes were strongly correlated. There was no significant difference between the mean H 2 O 2 concentration of the first and second test. We obtained a detection limit for the H 2 O 2 concentration of 0·02 μ moll −1 . The H 2 O 2 concentration appeared to remain stable for a period up to 40 days of freezing. Compared to previous studies we developed a more efficient breath condensate collecting device and obtained a lower H 2 O 2 detection limit. The measurement of exhaled H 2 O 2 was reproducible. In addition, storage of the samples up to 40 days showed no changes in H 2 O 2 concentration.

Exhaled and nasal NO (ENO, NNO) have been suggested as markers for inflammation in lower and upper respiratory tract respectively. It is still unknown how a number of factors, apart from airway inflammation, can influence NO levels. The aim of this study was to determine the effect of a nitrate-rich meal on ENO and NNO. Sixteen healthy subjects were observed during 1 week on normal diet before a nitrate-restricted diet was introduced in the next. On day 3 of the second week they were made to ingest a nitrate rich meal. ENO, NNO, plasma nitrate and plasma L -arginine were followed before the meal and afterwards for 3 h. ENO and NNO as well as plasma nitrate and plasma L -arginine were significantly elevated after the nitrate-rich meal. The median maximal increase of ENO and NNO was 47% and 13% respectively. We found a moderate but significant correlation between the rise in plasma nitrate and ENO (r s =0·57, P =0·027) but none between plasma nitrate and NNO (r s =−0·02, P =0·95). As nitrate in the diet seems to substantially influence the levels of ENO it is important either to restrict or register the intake of nitrate-rich food prior to measuring ENO.

Quitting smoking is a first-line treatment for patients with bronchial diseases. Continued smoking worsens the clinical course of chronic broncho-pulmonary diseases and increases the number of exacerbations. Specialists commonly insist on the need to quit smoking. This study sought to determine whether a percentage of patients seen in a respiratory medicine clinic continued to smoke while denying doing so. One hundred twenty-five subjects were studied consecutively. At a regular visit they were first asked about smoking; later, without prior warning, exhaled carbon monoxide (CO) was measured by co-oximetry. If CO was over 10 ppm, the subject was considered to have been smoking. We defined a patient as a "liar" if he or she denied smoking but had a reading of CO in exhaled air over 10. Of the 125 cases studied, 21 (17%) smoked while denying doing so. Among men the percentage was 21%, and among ex-smokers, the figure was 27%. The highest value, 34%, was found among patients with chronic obstructive pulmonary disease (COPD). We conclude, therefore, that a substantial proportion of patients lies to their physicians. A third of COPD patients, who are particularly sensitive to the toxic effects of smoking, try to mislead their doctors.

Nitrous oxide (N2O) is produced by denitrification, i.e. by microbial reduction of nitrate (NO3−). Our previous studies have established an analytical method for demonstrating the existence of N2O in exhaled air, and we showed that levels of N2O in exhaled air increase with age after puberty. However, the source of this change and its biological significance are still unclear. The purpose of this study was to examine whether the oral microorganisms are the main source of N2O. We measured exhaled N2O in 35 young adults (aged 19–29 years) and 34 older adults (aged 61–79 years) before and after mouth cleansing. N2O was measured using an infrared-photoacoustic analyzer equipped with an optical filter (UA0985, 2215 cm−1). Participants were classified as producers and non-producers according to the levels of exhaled N2O relative to the level in the atmosphere. N2O production differed significantly between the young adult producers and the older adult producers. Mouth cleansing resulted in an immediate reduction in exhaled N2O in both groups. We only found seven (20.0%) producers in the young, and 32 (94.1%) producers in the older after mouth washing. The differences before and after mouth cleansing were significant in both groups (P

The purpose of this study was to compare different biological methods in current use to assess benzene exposure. The methods involved in the study were: benzene in blood, urine and exhaled air, and the urinary metabolites t,t -muconic acid (MA) and S -phenylmercapturic acid ( S -PMA). Blood, urine and exhaled air samples were collected from workers in a benzene plant (pure benzene exposure) and cokery (mixed exposure, e.g. polycyclic aromatic hydrocarbons — PAHs) in an Estonian shale oil petrochemical plant. The benzene in these samples was analysed with a head-space gas chromatograph, and the metabolites MA and S -PMA with a liquid chromatograph using methods developed from published procedures. Some of the values measured in the Estonian shale oil area were high in comparison with those published during the last few years, whereas the values measured in the control group did not show any exposure to benzene except in the smokers group. The highest median exposure was in the benzene factory, 0.9 cm 3 /m 3 TWA (2.9 mg/m 3 ) and the highest individual value was 15 cm 3 /m 3 TWA (49 mg/m 3 ). All biological measurements in this study gave the same assessment about exposure to benzene and correlated highly significantly with each other and with the air measurements ( r = 0.8 or more). In the benzene factory the correlation was good even when calculated from samples with air concentration 3 /m 3 (3.2 mg/m 3 ) in the case of blood benzene and urinary MA. However, for S -PMA it was weak ( r = 0.4) and for benzene in urine and exhaled air it did not exist any more. In the cokery, with mixed exposure, the correlation at low levels was weaker even for blood benzene and urinary MA ( r = 0.6). According to the results in the benzene factory the exposure to pure benzene at the level 1 cm 3 /m 3 (3.25 mg/m 3 ) TWA gave: the blood benzene value about 110 nmol/l (8.6 μg/l), MA 23 μmol/l (3.3 μg/l) or 2.0 mg/g creatinine, S -PMA 58 μg/g creatinine or 0.4 μmol/l (95.7 μg/l), benzene in urine 499 nmol/l (39 μg/l), and benzene in the exhaled air 2.8 nmol/l (0.2 μg/l). In general, the measurement of benzene in blood and in exhaled air, as well as benzene and its metabolites MA and S -PMA in urine, all gave similar results. However, at low exposure level ( 3 /m 3 ) the most reliable analyses were MA in urine and benzene in blood.

Aerosol particles with aerodynamic diameters (d ac ) of about 1.1 μm were inspired into human conducting airways by the bolus inhalation technique. Inhaling small volumes of aerosols (“20 cm 3 - boluses”) at the very end of a clean air inhalation these particles should only reach conducting human airways. Particle recoveries (RC) in the exhaled air after various periods of breath holding (t b ) were measured in front of the mouth with an aerosol laser photometer. Assuming that losses of the inhaled particles were caused by sedimentation during breath holding periods, the slope of the recovery function (RC(t b )) is a measure of the airway dimensions where the particles were located at end inhalation. This function can be estimated theoretically. By comparing bolus recovery data to model calculations, assuming different aerosol distributions in airway models, and both still and stirred settling, it could be shown that aerosol boluses inhaled to lung depths 3 do not reach alveolar airspaces during inhalation.

The risk of infection transmitted during mouth-to-mouth or mouth-to-nose resuscitation procedures is difficult to define but is possibly quite low. However, the perceived risk is sufficient to cause serious concern for many individuals, including trained hospital personnel as well as the general public, and may preclude prompt and effective action. A novel airway device was evaluated for the retention of infective droplets and fluid permeability under simulated resuscitation conditions using a cardiopulmonary resuscitation training manikin. Retention of a 0.5-5.0 micron aerosol of Staphylococcus aureus cells was greater than 80% at flow rates of 6 l/min while under simulated resuscitation conditions the trapping of bacteria, originating predominantly from saliva, was over 90%. These data suggest that this device may afford significant protection against transmission of infection during exhaled air resuscitation manoeuvres.

To study the behaviour of inspired aerosols in human conducting airways during breathholding, inhalation experiments were carried out using monodisperse areosols with an aerodynamic particle diameter of about 1 μm. With a newly developed aerosol inhalation device (Scheuch et al. 1989) very small volumes of aerosols (boluses) were injected in a 1000 cm3 clean air inspiration and after a breathholding period (tb) dispersion of these boluses were measured in the exhaled air with a laser photometer. The boluses were inhaled to volumetric lung depths (VL) between 25 and 250 cm3 and breathholding periods (tb) were chosen up to 60 s. Injecting the boluses to VL > 50 cm3 bolus dispersion increased with increasing tb up to a maximum and decreased with even longer tb. This behaviour is mainly caused by cardiogenic flow oscillations (increase of broadening) and deposition due to gravitational settling (decrease).

Nitric oxide (NO) gas is produced by various cells within the lower respiratory tract, including inflammatory and epithelial cells, and is detectable in the exhaled air of normal human subjects. We have measured exhaled NO in patients with asthma, since several cell types that are activated in asthma can produce NO after induction. NO was measured reproducibly by a slow vital capacity manoeuvre and an adapted chemiluminescence analyser. NO was detectable in exhaled air of 67 control subjects (mean peak concentration 80.2 [SE 4.1] ppb) and was significantly reduced by inhalation of the specific NO synthase inhibitor NG-monomethyl-L-arginine. 61 non-steroid-treated asthmatic subjects had significantly higher peak expired NO concentrations than controls (283 [16] ppb, p0.001) but 52 asthmatic patients receiving inhaled corticosteroids had levels similar to controls (101 [7] ppb). High exhaled NO concentrations in asthmatic patients may reflect induction of NO synthase, which is known to be inhibited by steroids. Measurement of exhaled NO concentrations may be clinically useful in detection and management of cytokine-mediated inflammatory lung disorders.