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COPD is a prevalent, highly morbid, but manageable disease. Challenges exist in diagnosis that leads to both missed and inappropriate diagnosis with apparent ethnic, sex, and socioeconomic disparities. Disease management is possible with medications and intensive efforts such as pulmonary rehabilitation, but as these interventions are become increasingly expensive, the divide in socioeconomic outcomes expands. Health systems have increasingly focused resources on COPD, but the efforts have not been equally implemented. There is increasing prevalence of COPD in women, patients with low socioeconomic status, and minorities attributable to higher burden of tobacco, occupational, and rural exposure. Recent mortality estimates suggest a growing socioeconomic divide. As providers and healthcare systems work to improve the diagnosis and care of COPD patients, biases and disparities must be measured, appreciated, and addressed to assure just implementation.

This is the first known community transmission case of the novel coronavirus disease (COVID-19) in the United States, with significant public health implications. Diagnosis of COVID-19 is currently confirmed with PCR based testing of appropriate respiratory samples. Given the absence of travel or known exposure history, this patient did not meet the criteria for testing according to CDC guidelines at the time of her presentation. Since this case, any patient with severe disease (eg, ARDS or pneumonia) requiring hospitalization without an explanatory diagnosis can be tested even if no clear source of exposure is identified. While influencing national health policies for revising screening criteria, this case also highlighted significant knowledge gaps in diagnosis and treatment and a desperate need for early, widespread, fast and cheap testing for COVID-19.

Asthma is a heterogeneous disease, with multiple underlying inflammatory pathways and structural airway abnormalities that impact disease persistence and severity. Recent progress has been made in developing targeted asthma therapeutics, especially for subjects with eosinophilic asthma. However, there is an unmet need for new approaches to treat patients with severe and exacerbation-prone asthma, who contribute disproportionately to disease burden. Extensive deep phenotyping has revealed the heterogeneous nature of severe asthma and identified distinct disease subtypes. Acurrent challenge in the field is to translate new and emerging knowledge about different pathobiologic mechanisms in asthma into patient-specific therapies, with the ultimate goal of modifying the natural history of disease. Here, we describe the Precision Interventions for Severe and/or Exacerbation-Prone Asthma (PrecISE) Network, a groundbreaking collaborative effort of asthma researchers and biostatisticians from around the United States. The PrecISE Network was designed to conduct phase II/proof-of-concept clinical trials of precision interventions in the population with severe asthma, and is supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health. Using an innovative adaptive platform trial design, the PrecISE Network will evaluate up to 6 interventions simultaneously in biomarker-defined subgroups of subjects. We review the development and organizational structure of the PrecISE Network, and choice of interventions being studied. We hope that the PrecISE Network will enhance our understanding of asthma subtypes and accelerate the development of therapeutics for severe asthma.

Background Respiratory viral infections are common and potentially devastating to patients with underlying lung disease. Diagnosing viral infections often requires invasive sampling, and interpretation often requires specialized laboratory equipment. Here, we test the hypothesis that a breath test could diagnose influenza and rhinovirus infections using an in vitro model of the human airway. Methods Cultured primary human tracheobronchial epithelial cells were infected with either influenza A H1N1 or rhinovirus 1B and compared with healthy control cells. Headspace volatile metabolite measurements of cell cultures were made at 12-hour time points postinfection using a thermal desorption-gas chromatography-mass spectrometry method. Results Based on 54 compounds, statistical models distinguished volatile organic compound profiles of influenza- and rhinovirus-infected cells from healthy counterparts. Area under the curve values were 0.94 for influenza, 0.90 for rhinovirus, and 0.75 for controls. Regression analysis predicted how many hours prior cells became infected with a root mean square error of 6.35 hours for influenza- and 3.32 hours for rhinovirus-infected cells. Conclusions Volatile biomarkers released by bronchial epithelial cells could not only be used to diagnose whether cells were infected, but also the timing of infection. Our model supports the hypothesis that a breath test could serve to diagnose viral infections.

One of the most logical applications of modern breath analysis techniques is to provide information on respiratory infections. Ongoing work in various types of pulmonary infections has begun to denote candidate breath biomarkers of bacterial, viral, and fungal lung infections. Groundbreaking studies have been performed in naturally occurring cases with humans and with animal models of the disease. This has been coupled with cell culture work to understand the nature of the origins of breath biomarkers generated from the pathogen itself as it proliferates. Much work remains to be done, and the published studies described in this chapter are helping to set a foundation for this research area.

Respiratory viral infections are considered a major public health threat, and breath metabolomics can provide new ways to detect and understand how specific viruses affect the human pulmonary system. In this pilot study, we characterized the metabolic composition of human breath for an early diagnosis and differentiation of influenza viral infection, as well as other types of upper respiratory viral infections. We first studied the non-specific effects of planned seasonal influenza vaccines on breath metabolites in healthy subjects after receiving the immunization. We then investigated changes in breath content from hospitalized patients with flu-like symptoms and confirmed upper respiratory viral infection. The exhaled breath was sampled using a custom-made breath condenser, and exhaled breath condensate (EBC) samples were analysed using liquid chromatography coupled to quadruplole-time-of-flight mass spectrometer (LC-qTOF). All metabolomic data was analysed using both targeted and untargeted approaches to detect specific known biomarkers from inflammatory and oxidative stress biomarkers, as well as new molecules associated with specific infections. We were able to find clear differences between breath samples collected before and after flu vaccine administration, together with potential biomarkers that are related to inflammatory processes and oxidative stress. Moreover, we were also able to discriminate samples from patients with flu-related symptoms that were diagnosed with confirmatory respiratory viral panels (RVPs). RVP positive and negative differences were identified, as well as differences between specific viruses defined. These results provide very promising information for the further study of the effect of influenza A and other viruses in human systems by using a simple and non-invasive specimen like breath.

Chronic obstructive pulmonary disease (COPD) is a complex and heterogeneous syndrome that represents a major global health burden. COPD phenotypes have recently emerged based on large cohort studies addressing the need to better characterize the syndrome. Though comprehensive phenotyping is still at an early stage, factors such as ethnicity and radiographic, serum, and exhaled breath biomarkers have shown promise. COPD is also an immunological disease where innate and adaptive immune responses to the environment and tobacco smoke are altered. The frequent overlap between COPD and other systemic diseases, such as cardiovascular disease, has influenced COPD therapy, and treatments for both conditions may lead to improved patient outcomes. Here, we discuss current paradigms that center on improving the definition of COPD, understanding the immunological overlap between COPD and vascular inflammation, and the treatment of COPD—with a focus on comorbid cardiovascular disease.

The use of inhaled corticosteroids (ICSs) plays a key role in the treatment of asthmatic patients, and international guidelines have designated ICSs as an early maintenance therapy in controlling asthma symptoms. When asthmatic patients remain symptomatic on ICSs, one common option is to add a long-acting beta2 agonist (LABA) to the maintenance treatment. Fixed combination inhalers that contain both an ICS and a LABA have been popular for both chronic obstructive pulmonary disease (COPD) and asthma. Historically, these inhalers have been dosed twice daily. However, currently, there is a once-daily combination therapy with the ICS fluticasone furoate (FF) and the LABA vilanterol trifenatate (VI) with indications for use in both COPD and asthma. This dry powder inhaler (DPI) comes in two doses of FF (100 or 200 μg) both combined with VI (25 μg). This article reviews the clinical trial data for FF, VI and FF/VI combination inhalers and documents the efficacy and safety of once-daily inhaled maintenance therapy by DPI in asthmatic patients.

Asthma is a complex inflammatory disease with many triggers. The best understood asthma inflammatory pathways involve signals characterized by peripheral eosinophilia and elevated immunoglobulin E levels (called T2-high or allergic asthma), though other asthma phenotypes exist (eg, T2-low or non-allergic asthma, eosinophilic or neutrophilic-predominant). Common triggers that lead to poor asthma control and exacerbations include respiratory viruses, aeroallergens, house dust, molds, and other organic and inorganic substances. Increasingly recognized non-allergen triggers include tobacco smoke, small particulate matter (eg, PM2.5), and volatile organic compounds. The interaction between respiratory viruses and non-allergen asthma triggers is not well understood, though it is likely a connection exists which may lead to asthma development and/or exacerbations. In this paper we describe common respiratory viruses and non-allergen triggers associated with asthma. In addition, we aim to show the possible interactions, and potential synergy, between viruses and non-allergen triggers. Finally, we introduce a new clinical approach that collects exhaled breath condensates to identify metabolomics associated with viruses and non-allergen triggers that may promote the early management of asthma symptoms.

Airway obstruction from blood clots, airway secretions, and foreign bodies is a potentially life-threatening condition. Optimal management of this problem, whether by rigid or flexible bronchoscopy, has not been well studied. We report our single-center experience on the safety and clinical utility of cryoprobe extraction for this indication.We performed a retrospective chart review from January 2006 to November 2014 of all subjects aged 18 and older who underwent flexible bronchoscopic cryoprobe extraction. Subjects with obstruction due to benign or malignant neoplasm or airway stenosis were excluded.A total of 38 cryotherapy sessions performed on 30 subjects were identified for inclusion. Cryoprobe extraction was successful in reestablishing airway patency in 32/38 (84%) sessions overall and in 24/26 (92%) for blood clots, 4/6 (67%) for mucous plugging, 2/4 (50%) for foreign bodies, and 2/2 (100%) for plastic bronchitis. Twenty-one of 31 (68%) sessions resulted in improvement in oxygenation or ventilation. There was 1 complication related to sedation.We conclude that flexible bronchoscopic cryoprobe extraction of blood clots, mucous secretions, plastic bronchitis, and foreign bodies is a safe and effective option. It can be safely performed at the bedside and in many cases eliminates the need for rigid bronchoscopy.

Asthma affects over 300 million people worldwide. Asthmatics experience difficulty in breathing and airflow obstruction caused by inflammation and constriction of the airways. Home monitoring of lung function is the preferred course of action to give physicians and asthma patients a chance to control the disease jointly. Thus, it is important to develop accurate and efficient asthma monitoring devices that are easy for patients to use. While classic spirometry is currently the best way to capture a complete picture of airflow obstruction and lung function, the machines are bulky and generally require supervision. Portable peak flow meters are available but are inconvenient to use. There also exist no portable inexpensive exhaled breath biomarker devices commercially available to simultaneously measure concentrations of multiple chemical biomarkers. We have created a user-friendly, accurate, and portable external mobile device accessory that collects spirometry, peak expiratory flow, exhaled nitric oxide, carbon monoxide, and oxygen concentration information from patients after two breath maneuvers. We have also developed a software application that records and stores the gathered test information and e-mails the results to a physician. Telemetric capabilities help physicians to track asthma symptoms and lung function over time, which allow physicians the opportunity to make appropriate changes in a patient’s medication regimen more quickly.

Inhalation of cosmetic talc can lead to pulmonary foreign-body granulomatosis, though fewer than 10 cases of inhaled cosmetic talc-related pulmonary granulomatosis have been reported in adults. We report the case of a 64-year-old man with diffuse, bilateral pulmonary nodules and ground glass opacities associated with chronic inhalation of cosmetic talc. Transbronchial biopsy showed peribronchiolar foreign-body granulomas. After cessation of talc exposure, the patient demonstrated clinical and radiographic improvement without the use of corticosteroids. This case demonstrates that a conservative approach with cessation of exposure alone, without the use of corticosteroids, can be an effective therapy in cosmetic talc-related pulmonary granulomatosis.

Monitoring health conditions is essential to detect early asymptomatic stages of a disease. To achieve this, blood, urine and breath samples are commonly used as a routine clinical diagnostic. These samples offer the opportunity to detect specific metabolites related to diseases and provide a better understanding of their development. Although blood samples are commonly used routinely to monitor health, the implementation of a relatively noninvasive technique, such as exhaled breath condensate (EBC) analysis, may further benefit the well-being of both humans and other animals. EBC analysis can be used to track possible physical or biochemical alterations caused by common diseases of the bottlenose dolphin (Tursiops truncatus), such as infections or inflammatory-mediated processes. We have used an untargeted metabolomic method with liquid chromatography-mass spectrometry analysis of EBC samples to determine biomarkers related to disease development. In this study, five dolphins under human care were followed up for 1 year. We collected paired blood, physical examination information, and EBC samples. We then statistically correlated this information to predict specific health alterations. Three dolphins provided promising case study information about biomarkers related to cutaneous infections, respiratory infections, dental disease, or hormonal changes (pregnancy). The use of complementary liquid chromatography platforms, with hydrophilic interaction chromatography and reverse-phased columns, allowed us to detect a wide spectrum of EBC biomarker compounds that could be related to these health alterations. Moreover, these two analytical techniques not only provided complementary metabolite information but in both cases they also provided promising diagnostic information for these health conditions. Graphical abstract Collection of the exhaled condensed breath from a bottlenose dolphin from U.S. Navy Marine Mammal Program (MMP).

Exhaled breath condensate (EBC) analysis is a developing field with tremendous promise to advance personalized, non-invasive health diagnostics as new analytical instrumentation platforms and detection methods are developed. Multiple commercially-available and researcher-built experimental samplers are reported in the literature. However, there is very limited information available to determine an effective breath sampling approach, especially regarding the dependence of breath sample metabolomic content on the collection device design and sampling methodology. This lack of an optimal standard procedure results in a range of reported results that are sometimes contradictory. Here, we present a design of a portable human EBC sampler optimized for collection and preservation of the rich metabolomic content of breath. The performance of the engineered device is compared to two commercially available breath collection devices: the RTube™ and TurboDECCS. A number of design and performance parameters are considered, including: condenser temperature stability during sampling, collection efficiency, condenser material choice, and saliva contamination in the collected breath samples. The significance of the biological content of breath samples, collected with each device, is evaluated with a set of mass spectrometry methods and was the primary factor for evaluating device performance. The design includes an adjustable mass-size threshold for aerodynamic filtering of saliva droplets from the breath flow. Engineering an inexpensive device that allows efficient collection of metalomic-rich breath samples is intended to aid further advancement in the field of breath analysis for non-invasive health diagnostic. EBC sampling from human volunteers was performed under UC Davis IRB protocol 63701-3 (09/30/2014-07/07/2017).

The elderly patient (65 years and older) with chronic obstructive pulmonary disease (COPD) can be a challenge to the clinician. This begins with the correct and early diagnosis, the assessment of disease severity, recognizing complicating comorbidities, determining the burden of symptoms, and monitoring the frequency of acute exacerbations. Comprehensive management of COPD in the elderly patient should improve health-related quality of life, lung function, reduce exacerbations, and promote patient compliance with treatment plans. Only smoking cessation and oxygen therapy in COPD patients with hypoxemia reduce mortality. Bronchodilators, corticosteroids, methylxanthines, phosphodiesterase-4 inhibitors, macrolide antibiotics, mucolytics, and pulmonary rehabilitation improve some outcome measures such as spirometry measures and the frequency of COPD exacerbations without improving mortality. International treatment guidelines to reduce symptoms and reduce the risk of acute exacerbations exist. Relief of dyspnea and control of anxiety are important. The approach to each patient is best individualized. Earlier use of palliative care should be considered when traditional pharmacotherapy fails to achieve outcome measures and before consideration of end-of-life issues.

Hemophagocytic lymphohistiocytosis (HLH) is a rare but life-threatening disease caused by excessive immune activation. Acquired HLH is seen in adults and is often caused by infection or malignancy. Diagnosis is difficult and usually missed as clinical and laboratory findings are nonspecific. Moreover, the pathophysiology of the systemic inflammatory response syndrome and/or sepsis is remarkably similar to HLH. Thus, in patients presenting with presumed severe sepsis or septic shock complicated by multiorgan failure without a clear infectious source, HLH should be considered. A disproportionately high ferritin may be one of the earlier laboratory findings to suggest HLH. We discuss a case of a young male who presented with presumed septic shock with multiorgan failure who was eventually found to have Epstein-Barr virus–induced HLH.

Cough is an essential mechanism for airway clearance and protection, but it is also a troublesome symptom and one of the most commonly encountered in the outpatient setting across a variety of disciplines. Cough represents a challenge for primary care and specialty physicians alike given its pathophysiologic complexity, broad differential, and sometimes elusive nature. The global impact of cough on healthcare cost is substantial, and it is responsible for more than 30 million outpatient visits per year in the United States alone. This has prompted the development of national guidelines surrounding the diagnosis and management of cough.

Electronic cigarettes (e-cigarettes) have surged in popularity since their introduction in 2007. Sales of e-cigarettes and related products in the US were expected to exceed $1B in 2013. With the popularity of the electronic cigarette on the rise, physicians are sure to get questions from patients about the safety of e-cigarettes and their effectiveness as tools for smoking cessation or reduction. Most users of the electronic cigarette are so-called dual users—current cigarette smokers who also use e-cigarettes. The appeal of these devices is largely based on a perception that they are not as harmful as traditional cigarettes. Other factors that contribute to the popularity of e-cigarettes are that they have the look and feel of a traditional cigarette, that they can be used in locations where cigarette smoking is forbidden, and that they are perceived by smokers as tools to help to reduce or eliminate the smoking of traditional cigarettes. At present, e-cigarettes are not formally regulated for safety or quality control. As a result, nicotine delivery with these devices is not consistent. There is significant concern in the medical community that these e-cigarettes may not be as safe as is publicly perceived, particularly in the context of dual use. The use of e-cigarettes in harm-reduction strategies is a very divisive one in the public health arena. During the last few years, there have been longitudinal, cross-sectional, and randomized clinical trials evaluating the efficacy of electronic cigarettes as smoking cessation aids. This review presents a focused analysis of these studies.

Critical asthma syndrome represents the most severe subset of asthma exacerbations, and the critical asthma syndrome is an umbrella term for life-threatening asthma, status asthmaticus, and near-fatal asthma. According to the 2007 National Asthma Education and Prevention Program guidelines, a life-threatening asthma exacerbation is marked by an inability to speak, a reduced peak expiratory flow rate of

The critical asthma syndrome (CAS) encompasses the most severe, persistent, refractory asthma patients for the clinician to manage. Personalized pharmacotherapy is necessary to prevent the next acute severe asthma exacerbation, not just the control of symptoms. The 2007 National Asthma Education and Prevention Program Expert Panel 3 provides guidelines for the treatment of uncontrolled asthma. The patient’s response to recommended pharmacotherapy is highly variable which risks poor asthma control leading to frequent exacerbations that can deteriorate into CAS. Controlling asthma symptoms and preventing acute exacerbations may be two separate clinical activities with their own unique demands. Clinicians must be prepared to use the entire spectrum of asthma medications available but must concurrently be aware of potential drug toxicities some of which can paradoxically worsen asthma control. Medications normally prescribed for COPD can potentially be useful in the CAS patient, particularly those with asthma-COPD overlap syndrome. Immunomodulation with drugs like omalizumab in IgE-mediated asthma syndromes is one important approach. New and emerging drugs address unique aspects of airway inflammation and biology but at a significant financial cost. The pharmacology and toxicities of the agents that may be used in the treatment of CAS to control asthma symptoms and prevent severe exacerbations are reviewed.

Cigarette smoking is known to cause a wide range of damaging health outcomes; however, the effects of non-cigarette tobacco products are either unknown or perceived as less harmful than cigarettes. Smokeless tobacco, cigar smoking, and waterpipe smoking have increased in usage over the past few decades. Some experts believe that their use is reaching epidemic proportions. Factors such as a perception of harm reduction, targeted advertising, and unrecognized addiction may drive the increased consumption of non-cigarette tobacco products. In particular, the need for social acceptance, enjoyment of communal smoking activities, and exotic nature of waterpipe smoking fuels, in part, its popularity. The public is looking for "safer" alternatives to smoking cigarettes, and some groups advertise products such as smokeless tobacco and electronic cigarettes as the alternatives they seek. Though it is clear that cigar and waterpipe tobacco smoking are probably as dangerous to health as cigarette smoking, there is an opinion among users that the health risks are less compared to cigarette smoking. This is particularly true in younger age groups. In the cases of smokeless tobacco and electronic cigarettes, the risks to health are less clear and there may be evidence of a harm reduction compared to cigarettes. In this article, we discuss commonly used forms of non-cigarette tobacco products, their impacts on lung health, and relevant controversies surrounding their use.

Asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) is a commonly encountered yet loosely defined clinical entity. ACOS accounts for approximately 15-25% of the obstructive airway diseases and patients experience worse outcomes compared with asthma or COPD alone. Patients with ACOS have the combined risk factors of smoking and atopy, are generally younger than patients with COPD and experience acute exacerbations with higher frequency and greater severity than lone COPD. Pharmacotherapeutic considerations require an integrated approach, first to identify the relevant clinical phenotype(s), then to determine the best available therapy. The authors discuss the array of existing and emerging classes of drugs that could benefit those with ACOS and share their therapeutic approach. A consensus international definition of ACOS is needed to design prospective, randomized clinical trials to evaluate specific drug interventions on important outcomes such as lung function, acute exacerbations, quality of life and mortality.

Acute fibrinous and organizing pneumonia (AFOP) is an extremely rare, relatively new, and distinct histological pattern of acute lung injury characterized predominately by the presence of intra-alveolar fibrin and associated organizing pneumonia. AFOP may be idiopathic or associated with a wide spectrum of clinical conditions. It has a variable clinical presentation from mild respiratory symptoms to that similar to the acute respiratory distress syndrome. Currently there is no consensus on treatment, and corticosteroids previously were of unclear benefit. To date, there are less than 40 cases of AFOP reported in the literature and only one has been linked to hematopoietic stem cell transplantation. Here we report the first case series of 2 patients who developed AFOP following allogenic stem cell transplant that were successfully treated with high-dose corticosteroids.

Of all the vasculitides, Churg–Strauss Syndrome (CSS) is one of the least common. Though regarded as an ANCA-associated vasculitis, serologies may be negative in a high proportion of patients. As a systemic disorder, disease presentation may be highly variable. Here we discuss two challenging cases of CSS.

This chapter aims to provide the general clinician with a good understanding of available tests in the pulmonary function laboratory to help characterize asthma. It focuses on how tests are defined and performed, their limitations, their interpretations, and how to use them to follow asthma over time. Bronchoprovocation testing is also discussed, and utilization of arterial blood gas tests to help make acute triage decisions is reviewed. The key elements pertinent to each topic are listed in the “Key Points” at the beginning of this chapter.

Occupational asthma is the most common occupational lung disease. Work-aggravated asthma and occupational asthma are two forms of asthma causally related to the workplace, while reactive airways dysfunction syndrome is a separate entity and a subtype of occupational asthma. The diagnosis of occupational asthma is most often made on clinical grounds. The gold standard test, specific inhalation challenge, is rarely used. Low molecular weight isocyanates are the most common compounds that cause occupational asthma. Workers with occupational asthma secondary to low molecular weight agents may not have elevated specific IgE levels. The mechanisms of occupational asthma associated with these compounds are partially described. Not all patients with occupational asthma will improve after removal from the workplace.

Many patients with breathlessness and chronic obstructive lung disease are diagnosed with either asthma, COPD, or—frequently—mixed disease. More commonly, patients with uncharacterized breathlessness are treated with therapies that target asthma and COPD rather than one of these diseases. This common practice represents the difficulty in distinguishing these disorders clinically, particularly in patients with a history that does not easily differentiate asthma from COPD. A common clinical scenario is an older former smoker with partially reversible or fixed airflow obstruction and evidence of atopy, demonstrating “overlap” features of asthma and COPD. We stress that asthma-COPD overlap syndrome becomes more prevalent with advancing age as patients respond less favorably to guideline-recommended drug therapy. We review the similarities and differences in clinical characteristics between these disorders, and their physiologic and inflammatory profiles within the context of the aging patient. We underscore the difficulties in differentiating asthma from COPD in current or former smokers, share our institutional experience with overlap syndrome, and highlight the need for new research to better characterize and investigate this important clinical phenotype.

Progress in improving patient outcomes and advancing therapeutics in chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) is hampered by phenotypic heterogeneity and variable responsiveness to clinical interventions that are not fully explained by currently held disease paradigms for COPD and IPF. Although these chronic lung diseases differ in their geoepidemiology and immunopathogenesis, emerging evidence suggest that organ-specific autoimmunity may underlie subphenotypes of COPD and IPF. In particular, the links to tobacco smoking, diet, gender, and environment are explored in this review. We also highlight potential mechanisms that could guide future investigations in both laboratory and clinical settings. A paradigm shift is needed in how we think about COPD and IPF, based on geoepidemiology and a broader understanding of disease pathogenesis that may ultimately lead to new therapies and improved patient outcomes.

Asthma and chronic obstructive pulmonary disease (COPD) are distinct but clinically overlapping airway disorders which often create diagnostic and therapeutic dilemmas. Current strategies to discriminate these diseases are limited by insensitivity and poor performance due to biologic variability. We tested the hypothesis that a gas chromatograph / differential mobility spectrometer (GC/DMS) sensor could distinguish between clinically well-defined groups with airway disorders based on the volatile organic compounds (VOCs) obtained from exhaled breath. After comparing VOC profiles obtained from 13 asthma, 5 COPD, and 13 healthy control subjects, we found that VOC profiles distinguished asthma from healthy controls and also a subgroup of asthmatics taking the drug omalizumab from healthy controls. The VOC profiles could not distinguish between COPD and any of the other groups. Our results show a potential application of the GC/DMS for non-invasive and bedside diagnostics of asthma and asthma therapy monitoring. Future studies will focus on larger sample sizes and patient cohorts.