A snapshot of exhaled nitric oxide and asthma characteristics: experience from high to low income countries

German Asthma Net: Characterisation of responders to anti-IL-5 and anti-IL-5(R) therapy

INTRODUCTION

Previous studies of anti-IL-5/IL-5(R) therapies in severe asthma found that response was mainly predicted by indicators of good baseline disease control. However, long-term response predictors remain unclear.

METHODS

Responders to anti-IL-5/IL-5(R) therapy in the well-characterised, real-life, international German Asthma Net (GAN) registry were analysed using regression analyses. Response was defined by ≥50% reduction in exacerbations or corticosteroid dose, super-response by a complete stop of both, and remission additionally by controlled asthma (ACT score≥20).

RESULTS

Seventy-seven percent of 347 patients (55% female, 56.6±12.3 years, follow-up 20.3±13 months) were responders and showed improved exacerbation rates, asthma control, and corticosteroid treatment reduction. Response was independently predicted by inhaled corticosteroid dose (odds ratio [OR] 1.5; p = 0.014), exacerbation rate (OR 1.2; p = 0.009), and treatment duration (OR 1.05, p = 0.023). Univariately, blood eosinophil counts notably predicted response (OR 12.4; p = 0.004). Super-response was inversely associated with corticosteroid dependence and depression. Remission was associated with the absence of systemic corticosteroids, better asthma control, and FEV1 in litre.

CONCLUSIONS

These results underscore that long-term anti-IL-5/IL-5(R) therapy reduces exacerbation and corticosteroid burden, especially in patients with severe disease and high type 2 inflammatory burden. Contrastingly, low baseline corticosteroid use and markers of good asthma control predicted remission and super-responder status.

Adherence to asthma and COPD inhaled therapies in low- and middle-income countries: a narrative review

INTRODUCTION

In low-income and middle-income countries (LIMCs), defined based on the World Bank classification, non-adherence to respiratory therapies contributes to increasing mortality and morbidity due to chronic respiratory diseases. To address this issue, it is essential to identify and tackle underlying factors such as cultural beliefs, socioeconomic disparities, and limited access to healthcare resources and infrastructures. The absence of strategies that integrate community involvement, healthcare professional's training, economic policies, and educational programs exacerbates the disproportionate burden of chronic respiratory diseases in LIMCs.

AREAS COVERED

This review is based on a structured literature search across PubMed, Scopus, and Google Scholar (2000-2023) using terms relevant to asthma, COPD, adherence, and LMICs. The review examines key factors that hinder patients' adherence to Asthma and COPD medications in LIMCs, providing some insights into the issue and proposing concrete solutions.

EXPERT OPINION

Addressing non-adherence requires a multifaceted approach involving community engagement, educational initiatives, and improved healthcare infrastructure. Future research should focus on tailored interventions to enhance adherence and ultimately improve health outcomes for patients with chronic respiratory diseases in LMICs.

Comparison of usability and user-friendliness of three FeNO analyzers in a general population cohort of the LEAD study

Exhaled nitric oxide (FeNO) is a marker for airway inflammation measured by hand-held or stationary analyzers, but their usability was not previously assessed. NIOX VERO (CN), NObreath (BN), Vivatmo pro (BV), and CLD88 analyzer (reference, EC) were compared in a prospective study of the general population LEAD (Lung, hEart, sociAl, boDy) cohort, including the System Usability Scale and tests for equivalence at a clinically relevant range of ≤ 70 ppb with linear models and Bland-Altman plots. In 486 participants (62.4 ± 14.2 years old, 48.1% female), all hand-held analyzers had a good usability score, with BN scoring best. BV required the fewest attempts and time to measurement success, followed by BN. The FeNO results were clinically equivalent between devices (difference to EC 0.7-7.5 ppb) with increasing variability at higher FeNO values. The analyzers had an agreement of ≥ 95% at the threshold of ≥ 40 ppb. CN showed the lowest difference to EC, followed by BV. All portable analyzers showed good usability with an above-average usability score. The best usability score was observed with the BN device, while the BV device had the shortest measuring time and the fewest additional attempts. The lowest difference to the stationary EC analyzers was observed with the CN device.

Assessing the Impact of Metalworking Exposures on Respiratory Health: The Role of Fractional Exhaled Nitric Oxide Levels

OBJECTIVE

The significance of measuring Fractional Exhaled Nitric Oxide (FeNO) has grown, particularly in monitoring respiratory diseases like asthma. FeNO levels indicate inflammation and a rise in response to respiratory irritants. This study investigates whether repeated exposure to irritants in metal casting and coating leads to respiratory inflammation and assesses the benefits of including FeNO measurement in periodic occupational health screenings.

METHODS

This cross-sectional study involved 99 workers aged 18-65 in the foundry and metal coating sectors in the İkitelli Organized Industrial Zone. The study group included 54 workers exposed to metal dust and fumes, while the control group comprised 45 workers in non-exposure roles (e.g., secretarial, assembly, packaging). Data were collected through face-to-face interviews, recording demographics, smoking habits, symptoms. FeNO levels were measured and analyzed with pulmonary function test parameters.

RESULTS

FeNO levels were significantly higher in the study group compared to the control group (p = 0.02). No significant relationships were found between FeNO levels and age, height, weight, BMI, waist circumference, years of work, or symptom presence, but a significant negative correlation was observed between FeNO levels and FEV1/FVC. Additionally, current smokers had significantly lower FeNO levels compared to those who had quit or never smoked (study, p = 0.014; control, p = 0.011).

CONCLUSION

Monitoring FeNO levels in occupational health assessments may facilitate early intervention and preventive measures, protecting worker health. Incorporating FeNO measurement into periodic screenings could enhance occupational health practices.

Nitric oxide synthase inhibitors reduce the formation of neutrophil extracellular traps and alleviate airway inflammation in the mice model of asthma

Asthma, a widespread chronic inflammatory disease can contribute to different degrees of lung function damage. The objective of this study is to explore the potential effects of nitric oxide synthase (NOS) inhibitors in asthma using mice model induced by ovalbumin (OVA). BALB/c mice were treated with OVA to establish an asthma model. Mice were intranasally challenged with different NOS inhibitors and analyzed the impact of NOS inhibitors on the lung tissues and bronchoalveolar lavage fluid (BALF). Histopathological analysis was performed by Periodic Acid-Schiff (PAS) staining. Airway reactivity was assessed using methacholine challenge testing. The concentrations of nitric oxide (NO), Neutrophil extracellular traps (NETs), and cytokines were determined by enzyme-linked immunosorbent assay (ELISA) assay. NOS inhibitors effectively improved airway inflammation and reduced airway hyperresponsiveness. In addition, NOS inhibitors decreased the concentrations of NO, NETs, and inflammation in the airway and BALF. The decreased NO production and reduced NET formation in the lung indicate that NOS inhibitors inhibit the process of NET release to alleviate asthma.

Eosinophils in chronic obstructive pulmonary disease

Chronic Obstructive Pulmonary Disease (COPD) is a heterogeneous lung condition characterised by chronic respiratory symptoms, fixed airway obstruction and persistent inflammation that leads to a progressive airflow limitation. Although COPD has traditionally been linked to neutrophilic inflammation, recent studies have identified a subset of patients - approximately 20%-40% - with elevated eosinophil levels in blood and sputum. Emerging evidence suggests that eosinophilic inflammation has a pivotal role in a subset of COPD patients and may influence disease progression, exacerbation frequency and therapeutic responses. This narrative review provides a comprehensive analysis of the role of eosinophils in COPD with particular attention to their role as biomarkers in blood and sputum. We evaluate the prevalence of eosinophilic inflammation in COPD exanimating different thresholds used in blood and in sputum to define it. In addition, we focus on eosinophilic COPD phenotype as a treatable trait, emphasising recent evidence that supports the effectiveness of biological target therapy.

Diagnostic value of IgE, fractional of exhaled nitric oxide, and peripheral blood eosinophils in adult bronchial asthma and their relationship with disease severity

OBJECTIVE

To investigate the diagnostic value of immunoglobulin E (IgE), fractional of exhaled nitric oxide (FeNO), and peripheral blood eosinophils (EOS) in adult bronchial asthma and to analyze their relationship with asthma severity.

METHODS

A retrospective analysis was conducted on 336 patients diagnosed with bronchial asthma and admitted to Xi'an Fourth Hospital from January 2022 to January 2024, forming the asthma group. Additionally, another 127 healthy subjects were selected as the non-asthmatic control group. The patients in the asthma group were categorized into a mild asthma group (n=138), a moderate asthma group (n=115), and a severe asthma group (n=83) according to the severity of the disease. Clinical data, lung function indices, and IgE, FeNO, and EOS levels were compared across groups. ROC curves were used to assess the diagnostic value of IgE, FeNO, and EOS levels for bronchial asthma. Spearman's rank correlation analysis was used to analyze the correlation between IgE, FeNO, EOS and other indicators and asthma severity.

RESULTS

The levels of IgE, FeNO, and EOS were significantly higher in the asthma group than those in the non-asthma group, while lung function indices, peak expiratory flow rate (PEF) and forced expiratory volume in 1 s (FEV1), were significantly lower (all P < 0.05). The areas under curve (AUCs) of IgE, FeNO, and EOS for the diagnosis of asthma were 0.79, 0.93, and 0.88, respectively. Significant differences were observed in smoking history, family history of asthma, co-existing allergic rhinitis, and combined atopic eczema across different severity groups (all P < 0.05). Spearman's rank correlation analysis showed that IgE, FeNO, and EOS were positively correlated with asthma severity (all P < 0.05), with r s values of 0.718, 0.679, and 0.540, respectively.

CONCLUSION

IgE, FeNO, and EOS are valuable in diagnosing bronchial asthma in adults. Higher levels of IgE, FeNO, and EOS correspond to increased asthma severity, making these biomarkers useful for assessing asthma severity.

Breath and Sputum Analyses in Asthmatic Patients: An Overview

Recent advancements in asthma management include non-invasive methodologies such as sputum analysis, exhaled breath condensate (EBC), and fractional exhaled nitric oxide (FeNO). These techniques offer a means to assess airway inflammation, a critical feature of asthma, without invasive procedures. Sputum analysis provides detailed insights into airway inflammation patterns and cellular composition, guiding personalized treatment strategies. EBC collection, reflecting bronchoalveolar lining fluid composition, provides a non-invasive window into airway physiology. FeNO emerges as a pivotal biomarker, offering insights into eosinophilic airway inflammation and aiding in asthma diagnosis, treatment monitoring, and the prediction of exacerbation risks. Despite inherent limitations, each method offers valuable tools for a more comprehensive assessment of asthma. Combining these techniques with traditional methods like spirometry may lead to more personalized treatment plans and improved patient outcomes. Future research is crucial to refine protocols, validate biomarkers, and establish comprehensive guidelines in order to enhance asthma management with tailored therapeutic strategies and improved patient outcomes.

Exhaled Nitric Oxide fraction in asthma and obstructive sleep apnea among children at high altitudes. A cross-sectional study

INTRODUCTION

Exhaled nitric oxide fraction (FeNO) is employed for the diagnosis and phenotyping of asthma as an inflammatory biomarker of the airway. Limited evidence exists regarding its behavior in the presence of asthma and obstructive sleep apnea (OSA). Our objective was to determine whether FeNO levels are associated with the severity of OSA or the coexistence of asthma and OSA in residents at high altitudes.

MATERIALS AND METHODS

Observational, analytical, cross-sectional study in children aged 5-16 years residing at 2600 m above sea level treated at a Sleep Study Center between 2019 and 2021. We conducted a medical history, polysomnogram, and measurement of FeNO levels. The children were categorized into four groups: OSA, asthma, asthma with OSA, and controls (without asthma or OSA). FeNO levels among the groups were compared using the Kruskal-Wallis test, and correlations were explored using the Spearman correlation coefficient. Analyses considered statistical significance at a two-tailed p-value <0.05.

RESULTS

Among the 261 included children, 68 (26.1 %) had OSA, 42 (16.1 %) were diagnosed with asthma, 109 (41.8 %) had both asthma and OSA, and 42 (16.1 %) were controls. Their FeNO medians were 10 ppb, 18.5 ppb, 15 ppb, and 14 ppb, respectively, with no significant differences between the evaluated groups (p = 0.263). We found no correlation between FeNO and apnea-hypopnea index and obstructive apnea index even for the groups of patients with FeNO >20 ppb and FeNO >35 ppb (>75th percentile). In the adjusted model, a significant association was observed between asthma and FeNO levels.

CONCLUSIONS

Our findings suggest that FeNO measurements in children would not allow establishing this biomarker as part of the diagnosis of OSA. However, these findings may be related to high altitude.

Biomonitoring Environmental Exposure in Syrian Refugees in Lebanon

Over one million Syrian refugees have been residing in substandard living conditions in Lebanon for the past decade. Non-invasive biomonitoring of fractional exhaled nitric oxide (FeNO) as a pulmonary inflammation biomarker was conducted following and preceding indoor environmental assessments (which revealed elevated mould counts in informal tented settlements and non-residential shelters) to further evaluate effects of environmental exposure to indoor contaminants. Results of biomonitoring (n = 57) provided some insight regarding existing respiratory conditions and the possible implementation of minimally invasive methods to establish susceptibility profiles in Syrian refugees amid limited access to healthcare. The clinical interpretation of FeNO results suggested possible persistent exposure to allergens in addition to significant type 2 inflammation in some subjects. These findings warrant the need to expand this study, investigate other biomarkers, and attempt to correlate findings with environmental conditions to evaluate if a dose-response relationship exists.

Oral bacterial composition associated with lung function and lung inflammation in a community-based Norwegian population

BACKGROUND

The oral cavity is the gateway to the bacteria community in the lung. Disruption of the symbiotic balance of the oral microbiota has been associated with respiratory diseases. However, little is known about the relationship between oral bacteria and respiratory outcomes in the general population. We aimed to describe the associations between oral bacteria, lung function, and lung inflammation in a community-based population.

METHODS

Oral (gingival) samples were collected concurrently with spirometry tests in 477 adults (47% males, median age 28 years) from the RHINESSA study in Bergen, Norway. Bacterial DNA from the 16S rRNA gene from gingival fluid were sequenced by Illumina^®MiSeq. Lung function was measured using spirometry and measurement of fractional exhaled nitric oxide (FeNO) were performed to examine airway inflammation. Differential abundance analysis was performed using ANCOM-BC, adjusting for weight, education, and smoking.

RESULTS

The abundance of the genera Clostridiales, Achromobacter, Moraxella, Flavitalea and Helicobacter were significantly different among those with low FEV₁ (< lower limit of normal (LLN)) as compared to normal FEV₁ i.e. ≥ LLN. Twenty-three genera differed in abundance between among those with low FVC < LLN as compared to normal FEV₁ ≥ LLN. The abundance of 27 genera from phyla Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria and Sacchribacteria differed significantly between elevated FeNO levels (≥ 50 ppb) compared to FeNO ≤ 25 ppb.

CONCLUSION

Oral bacterial composition was significantly different for those with low FEV or FVC as compared to those with normal lung function equal to or higher than LLN. Differential bacterial composition was also observed for elevated FeNO levels.

Update on the Role of FeNO in Asthma Management

Asthma is a heterogenous disorder characterized by presence of different phenotypes and endotypes. Up to 10% of the individuals suffer from severe asthma and are at increased risk of morbidity and mortality. Fractional exhaled nitric oxide (FeNO) is a cost-effective, point of care biomarker that is used to detect type 2 airway inflammation. Guidelines have proposed to measure FeNO as an adjunct to diagnostic evaluation in individuals with suspected asthma and to monitor airway inflammation. FeNO has lower sensitivity, suggesting that it may not be a good biomarker to rule out asthma. FeNO may also be used to predict response to inhaled corticosteroids, predict adherence and deciding on biologic therapy. Higher levels of FeNO have been associated with lower lung function and increased risk for future asthma exacerbations and its predictive value increases when combined with other standard measurements of asthma assessment.

Association of fractional exhaled nitric oxide with asthma morbidity in urban minority children

OBJECTIVE

Fractional exhaled nitric oxide (FeNO) is a well-established measure of allergic airway inflammation and possible useful adjunct disease management tool. We investigated the association of baseline and follow-up FeNO measurements with disease burden in minority children with persistent asthma.

METHODS

A retrospective chart review was conducted on 352 African American and Hispanic children seen at an urban Asthma Center in Bronx, NY. Demographic, clinical characteristics, and pulmonary function tests (PFTs) were compared between children with low, intermediate, and high baseline FeNO levels. Among 95 children with subsequent follow up visits, associations of change in FeNO with demographics, clinical characteristics, and PFTs were examined using mixed effects linear regression models.

RESULTS

A higher proportion of children with intermediate (54%) and high FeNO (58%) levels had lower airways obstruction compared to those with low FeNO levels (33%). Children with intermediate FeNO levels had more annual hospitalizations (2.8 ± 6.2) compared to those with low and high FeNO levels (1.3 ± 2.8 and 1.3 ± 2.5). These associations did not differ between ethnicities. An increase in FeNO over time was associated with higher BMI z-scores (β = 6.2, 95% CI: 1.0 to 11.4) and two or more hospitalizations in the past year (β = 16.1, 95% CI: 1.5 to 30.8).

CONCLUSIONS

Intermediate and high FeNO levels are associated with lower airways obstruction and hospitalizations. Initial and serial FeNO measurements can be a useful adjunctive tool in identifying asthma-related morbidity in urban African American and Hispanic children.

Fungi composition in settled dust associated with fractional exhaled nitric oxide in school children with asthma

Fungi exposure has been significantly linked to respiratory illness. However, numerous fungi taxa that are potentially allergenic still undocumented and leave a barrier to establishing a clear connection between exposure and health risks. This study aimed to evaluate the association of fungi composition in settled dust with fractional exhaled nitric oxide (FeNO) levels among school children with doctor-diagnosed asthma. A cross-sectional study was undertaken among secondary school students in eight schools in the urban area of Hulu Langat, Selangor, Malaysia. A total of 470 school children (aged 14 years old) were randomly selected and their FeNO levels were measured and allergic skin prick tests were conducted. The settled dust samples were collected and analysed by using metagenomic technique to determine the fungi composition. The general linear regression with complex sampling was employed to determine the interrelationship. In total, 2645 fungal operational taxonomic units (OTUs) were characterised from the sequencing process which belongs to Ascomycota (60.7 %), Basidiomycota (36.4 %), Glomeromycota (2.9 %) and Chytridiomycota (0.04 %). The top five mostly abundance in all dust samples were Aspergillus clavatus (27.2 %), followed by Hyphoderma multicystidium (12.2 %), Verrucoconiothyrium prosopidis (9.4 %), Ganoderma tuberculosum (9.2 %), and Heterochaete shearii (7.2 %). The regression results indicated that A. clavatus, Brycekendrickomyces acaciae, Candida parapsilosis, Hazslinszkyomyces aloes, H. multicystidium, H. shearii, Starmerella meliponinorum, V. prosopidis were associated in increased of FeNO levels among the asthmatic group at 0.992 ppb (95 % CI = 0.34-1.68), 2.887 ppb (95 % CI = 2.09-3.76), 0.809 ppb (95 % CI = 0.14-1.49), 0.647 ppb (95 % CI = 0.36-0.94), 1.442 ppb (95 % CI = 0.29-2.61), 1.757 ppb (95 % CI = 0.59-2.87), 1.092 ppb (95 % CI = 0.43-1.75) and 1.088 ppb (95 % CI = 0.51-1.62), respectively. To our knowledge, this is a new finding. The findings pointed out that metagenomics profiling of fungi could enhance our understanding of a complex interrelation between rare and unculturable fungi with airway inflammation.

Structure Effect on the Response of ZnGa2O4 Gas Sensor for Nitric Oxide Applications

We fabricated a gas sensor with a wide-bandgap ZnGa₂O₄ (ZGO) epilayer grown on a sapphire substrate by metalorganic chemical vapor deposition. The ZGO presented (111), (222) and (333) phases demonstrated by an X-ray diffraction system. The related material characteristics were also measured by scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. This ZGO gas sensor was used to detect nitric oxide (NO) in the parts-per-billion range. In this study, the structure effect on the response of the NO gas sensor was studied by altering the sensor dimensions. Two approaches were adopted to prove the dimension effect on the sensing mechanism. In the first approach, the sensing area of the sensors was kept constant while both channel length (L) and width (W) were varied with designed dimensions (L × W) of 60 × 200, 80 × 150, and 120 ×100 μm². In the second, the dimensions of the sensing area were altered (60, 40, and 20 μm) with W kept constant. The performance of the sensors was studied with varying gas concentrations in the range of 500 ppb~10 ppm. The sensor with dimensions of 20 × 200 μm² exhibited a high response of 11.647 in 10 ppm, and 1.05 in 10 ppb for NO gas. The sensor with a longer width and shorter channel length exhibited the best response. The sensing mechanism was provided to explain the above phenomena. Furthermore, the reaction between NO and the sensor surface was simulated by O exposure of the ZGO surface in air and calculated by first principles.

Understanding the Cellular Sources of the Fractional Exhaled Nitric Oxide (FeNO) and Its Role as a Biomarker of Type 2 Inflammation in Asthma

Fractional exhaled nitric oxide (FeNO) has gained great clinical importance as a biomarker of type 2 inflammation in chronic airway diseases such as asthma. FeNO originates primarily in the bronchial epithelium and is produced in large quantities by the enzyme inducible nitric oxide synthase (iNOS). It should be noted that nitric oxide (NO) produced at femtomolar to picomolar levels is fundamental for respiratory physiology. This basal production is induced in the bronchial epithelium by interferon gamma (IFNγ) via Janus kinases (JAK)/STAT-1 signaling. However, when there is an increase in the expression of type 2 inflammatory cytokines such as IL-4 and IL-13, the STAT-6 pathway is activated, leading to overexpression of iNOS and consequently to an overproduction of airway NO. Increased NO levels contributes to bronchial hyperreactivity and mucus hypersecretion, increases vascular permeability, reduces ciliary heartbeat, and promotes free radical production, airway inflammation, and tissue damage. In asthmatic patients, FeNO levels usually rise above 25 parts per billion (ppb) and its follow-up helps to define asthma phenotype and to monitor the effectiveness of corticosteroid treatment and adherence to treatment. FeNO is also very useful to identify those severe asthma patients that might benefit of personalized therapies with monoclonal antibodies. In this review, we revised the cellular and molecular mechanisms of NO production in the airway and its relevance as a biomarker of type 2 inflammation in asthma.

Evaluation of the Relationship between Fractional Exhaled Nitric Oxide (FeNO) with Indoor PM10, PM2.5 and NO2 in Suburban and Urban Schools

Numerous epidemiological studies have evaluated the association of fractional exhaled nitric oxide (FeNO) and indoor air pollutants, but limited information available of the risks between schools located in suburban and urban areas. We therefore investigated the association of FeNO levels with indoor particulate matter (PM10 and PM2.5), and nitrogen dioxide (NO2) exposure in suburban and urban school areas. A comparative cross-sectional study was undertaken among secondary school students in eight schools located in the suburban and urban areas in the district of Hulu Langat, Selangor, Malaysia. A total of 470 school children (aged 14 years old) were randomly selected, their FeNO levels were measured, and allergic skin prick tests were conducted. The PM2.5, PM10, NO2, and carbon dioxide (CO2), temperature, and relative humidity were measured inside the classrooms. We found that the median of FeNO in the school children from urban areas (22.0 ppb, IQR = 32.0) were slightly higher as compared to the suburban group (19.5 ppb, IQR = 24.0). After adjustment of potential confounders, the two-level hierarchical multiple logistic regression models showed that the concentrations of PM2.5 were significantly associated with elevated of FeNO (>20 ppb) in school children from suburban (OR = 1.42, 95% CI = 1.17−1.72) and urban (OR = 1.30, 95% CI = 1.10−1.91) areas. Despite the concentrations of NO2 being below the local and international recommendation guidelines, NO2 was found to be significantly associated with the elevated FeNO levels among school children from suburban areas (OR = 1.11, 95% CI = 1.06−1.17). The findings of this study support the evidence of indoor pollutants in the school micro-environment associated with FeNO levels among school children from suburban and urban areas.

Exhaled Nitric Oxide Level in Pharynx Angioedema

Airway inflammation is related to increased nitric oxide production. It can be assessed noninvasively with exhaled nitric oxide measurement. As airway inflammation was supposed to be present in chronic urticaria and angioedema patients we hypothesized increased exhaled nitric oxide in this group. Twenty-six symptomatic chronic urticaria patients with an acute episode of pharynx angioedema (17 women and 9 men, median age 35) were included in the study group. None of the patients reported a history of asthma, allergic rhinitis or cigarette smoking. The control group consisted of 29 non-smoking healthy subjects (19 women and 10 men, median age 22) without any history of atopy. Exhaled nitric oxide measurement was performed in all subjects. Exhaled nitric oxide levels in the angioedema group did not differ statistically significantly from those detected in healthy subjects (15.5 ppb and 17.0 ppb respectively). Our results indicate the lack of airway inflammation in chronic urticaria patients with pharynx angioedema.

Therapeutic gases used in balneotherapy and rehabilitation medicine - scientific relevance in the last ten years (2011 – 2020) - Synthetic literature review

ABSTRACT: Background. The medical relevance of therapeutic gases can range from use in burns and stroke victims to hypoxia therapy in children. However, medical gases such as oxygen, hydrogen, helium and xenon have recently come under increased exploration for their potential therapeutic use on various brain disease states, including traumatic brain injuries, hypoxia-ischemia and, cerebral hemorrhages. Objective. This synthetic review aims to rigorously select related articles and identify within their content the main possible uses of therapeutic gases and physiological mechanisms. The objective of this article is to present the various therapeutic mechanisms that have been proposed in the current literature and the medical relevance of various therapeutic gases used in balneotherapy or medical rehabilitation. Methods. To elaborate our synthesis review, we have searched for relevant open access articles in 6 international databases: Cochrane, Elsevier, NCBI/PubMed, NCBI/PMC, PEDro, and ISI Web of Knowledge/Science, published from January 2011 until December 2020. The contextually quested keywords combinations/ syntaxes used specified on this page. The eligible articles were analyzed in detail regarding pathologies addressed by therapeutic gases. All articles with any design (reviews, randomized controlled trials, non-randomized controlled trials, case-control studies, cross-sectional studies), if eligible according to the above-mentioned selection methodology, containing in the title or abstract the above-mentioned combinations, were included in the analysis. Articles were excluded in the second phase if they did not reach the relevance criterion. Results. Our search identified, first, 225 articles. After eliminating the duplicates, remained 180 articles. In the second phase, we applied a relevance criterion. Although our team - including the authors of this paper – have quite long and consistent expertise in achieving systematic literature reviews, the marked heterogeneity of both the item composing the subject we have approached and inherently the wase of presentations in the respective quite vast and diverse domain of medical gases, prevented us to fulfil, at least regarding this initial work, a systematic literature review. Instead, we succeeded to make a hopefully interesting and valuable narrative synthetic-related literature review. At the end of the second phase, 63 articles passed the relevance criterion and were included in this synthetic review. Conclusions. Therapeutic gases are not fully understood and used adequately for sanogenic or medical purposes. More research is needed to fully understand the mechanisms and importance of therapeutic gases. The link between balneotherapy and medical rehabilitation regarding the usage of therapeutical gases emphasises the unity for this medical speciality. Keywords: "Therapeutic gas"/ "Oxygen therapy"/ "Carbon dioxide"/ "CO2 therapy"/ "Carbon monoxide"/ "Mofette"/ "Hydrogen Sulfide"/ "H2S"/ "Helium"/ "Xenon"/ "Ozone therapy"/ "Radon"/ "Hydrogen therapy"/ "Nitric oxide"/ "Heliox" AND "Rehabilitation".