Fractional Exhaled Nitric Oxide Test Research Articles

Correlation of fractional exhaled nitric oxide (FeNO) and clinical outcomes in patients with chronic obstructive pulmonary disease: A prospective cohort study

BackgroundFractional exhaled nitric oxide (FeNO) is an acceptable and noninvasive marker for defining eosinophilic airway inflammation. Further study is necessary to clarify the role of FeNO in patients with chronic obstructive pulmonary disease (COPD). This study aimed to determine the association between FeNO levels and clinical outcomes. MethodsA prospective observational study was conducted at Songklanagarind Hospital from October 2020 to November 2022. FeNO testing and spirometry were performed at the initial visit and 12-month follow-up. Exacerbation, hospitalization, lung function decline, and all-cause mortality were analyzed to determine the association between FeNO levels and clinical outcomes. ResultsA total of 60 patients with COPD were enrolled, 88.3 % of whom were male, with a mean age of 71.3 ± 9.5 years. There were 18 patients (30 %) in the high FeNO group (≥25 ppb) and 42 patients (70 %) in the low (<25 ppb) FeNO group. The mean blood eosinophil count (BEC) was significantly higher in the high FeNO group (p < 0.001). After a 12-month follow-up period, high FeNO group had higher exacerbation events (HR of 1.26, 95 % confidence interval (CI), 1.10–1.97, p= 0.025). Hospitalization and mortality rates were significantly higher in the high FeNO group. Regardless of the inhaled corticosteroids used, patients with high BEC and FeNO levels tended to have a greater risk of exacerbation. ConclusionIn patients with COPD, FeNO levels are strongly correlated with BEC. Poor clinical outcomes were reported in patients with high FeNO levels. FeNO may be a useful biomarker for predicting clinical outcomes in patients with COPD.

Association between exposure to airborne trichloramine and health effects in indoor swimming pool workers.

The main objective of this study was to comprehensively investigate the association between trichloramine (TCA) exposure and respiratory health effects in swimming pool workers. In this study, air sampling was performed for TCA concentrations at fixed locations (static measurements) and on individual workers (personal measurements) in six indoor public swimming pools during periods of high swimmer attendance over the winter school break. Health effects were evaluated using questionnaires and fractional exhaled nitric oxide (FENO) tests performed before and after the working day. In these swimming pools, the environmental TCA concentration ranged from 0.11 to 0.88mg/m³. Worker exposure ranged from 0.05 to 0.72mg/m³ for personal measurements. Furthermore, in each swimming pool, the average worker exposure to TCA exceeded the recommended occupational exposure limit of 0.35mg/m³. Personal TCA measurements were consistently lower than static measurements performed around the pool, with a reduction ranging from 21% to 49%. This can be explained by the time that the workers spend in the pool area, office, and break room. The most common respiratory health effects self-reported by the workers were coughing, shortness of breath, and sneezing with prevalence rates of 38%, 37%, and 35%, respectively. This study demonstrated an association between TCA exposure and eye irritation. Analysis of the FENO tests revealed that individuals with preexisting asthma or allergies exhibited sustained FENO elevation. The findings suggest that occupational exposure to TCA in indoor swimming pools is a matter of concern. Implementing and improving workplace safety measures is crucial for safeguarding the respiratory health of swimming pool workers.

Pets, furry animal allergen components, and asthma in childhood

AbstractBackgroundThe use of component‐resolved allergy diagnostics has provided a clearer understanding of the species‐specific sensitization and severity of potential allergic reactions. This cross‐sectional study aimed to determine whether sensitization to allergen components in furry animals is indicative of blood eosinophilia, a positive fractional exhaled nitric oxide (FeNO) test, abnormal lung function, and asthma symptoms in children. Additionally, we investigated whether having pets during childhood affects the development of asthma or allergic sensitization to furry animals.MethodsWe recruited 203 children aged 4–17 years with asthma diagnosis based on abnormal lung function and 33 controls. IgE‐sensitization to allergen components for dogs, cats, and horses was analyzed using a multiplex microarray. Children were tested with FeNO, impulse oscillometry, spirometry, methacholine challenge, and skin prick test. A questionnaire was used to investigate pet ownership and symptom profile.ResultsFeNO results and blood eosinophilia revealed a correlation with sensitization to all furry animal allergens, particularly lipocalins (r = 0.203–0.560 and 0.206–0.560, respectively). Can f 3 was found to correlate with baseline R5 (r = 0.298). No association between methacholine challenge results and sensitization to furry animal allergens was found. Children with asthma who were sensitized to Can f 1, Can f 6, or both frequently reported asthma symptoms. Dog ownership was associated with a lower level of IgE‐sensitization to lipocalins, fewer asthma symptoms, and less blood eosinophilia.ConclusionFurry animal allergen component IgE‐sensitization is a risk factor for type 2‐inflammation and asthma symptoms.

Fractional exhaled nitric oxide-a possible biomarker for risk of obstructive sleep apnea in snorers.

Airway inflammation in patients with obstructive sleep apnea (OSA) has been described and can be assessed by measuring the biomarker fractional exhaled nitric oxide (FeNO). In this pilot study, we investigated FeNO measurements in identification of OSA among persons with snoring. In this study we aimed to investigate (1) if FeNO could be used in screening for OSA, (2) if daytime sleepiness correlated to FeNO levels, and (3) whether asthma affected FeNO levels. Persons with snoring were prospectively included in three primary care ear, nose, and throat clinics. Patients underwent spirometry, FeNO tests, and partial polygraphy. They filled out questionnaires on sinonasal and asthma symptoms, daytime sleepiness, and quality of life. Current smokers, patients with upper airway inflammatory conditions, and patients treated with steroids were excluded. Forty-nine individuals were included. Median apnea-hypopnea index was 11.4, mean age was 50.9 years, and 29% were females. OSA was diagnosed in 73% of the patients of whom 53% had moderate-severe disease. Patients with moderate-severe OSA had significantly higher FeNO counts than patients with no or mild OSA (P = .024). Patients younger than 50 years with a FeNO below 15 had the lowest prevalence of moderate-severe OSA. No correlation was found between FeNO measurements and daytime sleepiness, and asthma did not affect FeNO levels. We found a low prevalence of moderate-severe OSA in persons with snoring when FeNO and age were low. This might be considered in a future screening model, though further studies testing the FeNO cutoff level and the diagnostic accuracy are warranted. Registry: ClinicalTrials.gov; Name: NO Measurements in Screening for Asthma and OSA, in Patients With Severe Snoring; URL: https://clinicaltrials.gov/study/NCT03964324; Identifier: NCT03964324. Kiaer E, Ravn A, Jennum P, etal. Fractional exhaled nitric oxide-a possible biomarker for risk of obstructive sleep apnea in snorers. J Clin Sleep Med. 2024;20(1):85-92.

Asthma, Airflow Obstruction, and Eosinophilic Airway Inflammation Prevalence in Western Kenya: A Population-Based Cross-Sectional Study.

Objectives: Determine the prevalence of airway disease (e.g., asthma, airflow obstruction, and eosinophilic airway inflammation) in Kenya, as well as related correlates of airway disease and health-related quality of life. Methods: A three-stage, cluster-randomized cross-sectional study in Uasin Gishu County, Kenya was conducted. Individuals 12years and older completed questionnaires (including St. George's Respiratory Questionnaire for COPD, SGRQ-C), spirometry, and fractional exhaled nitric oxide (FeNO) testing. Prevalence ratios with 95% confidence intervals (CIs) were calculated. Multivariable models were used to assess correlates of airflow obstruction and high FeNO. Results: Three hundred ninety-two participants completed questionnaires, 369 completed FeNO testing, and 305 completed spirometry. Mean age was 37.5years; 64% were women. The prevalence of asthma, airflow obstruction on spirometry, and eosinophilic airway inflammation was 21.7%, 12.3% and 15.7% respectively in the population. Women had significantly higher SGRQ-C scores compared to men (15.0 vs. 7.7). Wheezing or whistling in the last year and SGRQ-C scores were strongly associated with FeNO levels >50ppb after adjusting for age, gender, BMI, and tobacco use. Conclusion: Airway disease is a significant health problem in Kenya affecting a young population who lack a significant tobacco use history.

Economic impact of a more extensive use of FENO testing on the Italian population with asthma

BackgroundAsthma is a common chronic inflammatory airway affecting over 260 million people worldwide, and characterized, in the large majority of cases, by the so-called “type 2 inflammation”. Fractional exhaled nitric oxide (FENO) testing is noninvasive point-of-care tool to assess type 2 inflammation and therefore improve asthma management. It has been suggested to determine eligibility for a specific biologic therapy and predict likelihood to respond. The aim of this study was to estimate the overall economic impact of an extensive use of FENO testing on the Italian population with asthma, including extra costs of testing and savings generated by more appropriate prescriptions, increased adherence and lower frequency of exacerbations.MethodsA cost of illness analysis was firstly performed to estimate the yearly economic burden from the National Healthcare Service (NHS) perspective in Italy of the management of asthmatic patients with standard of care (SOC) according to the application of GINA (Global Initiative for Asthma) guidelines; then, we evaluated the changes in the economic burden in patient management by introducing FENO testing into clinical practice. The cost items considered were: visits/exams, exacerbations, drugs, management of adverse events caused by short-term oral corticosteroids use. Efficacy of FeNO test and SOC is based on literature evidence. Costs refer to published data or Diagnosis Related Group/outpatient tariffs.ResultsConsidering one asthma visit every 6 months, the total yearly cost for the management of patients with asthma in Italy is 1,599,217,876€ (409.07€ per patient), while for FENO testing strategy this figure is 1,395,029,747€ (356.84€ per patient). An increased utilization rate of FENO testing from 50 to 100% of patients may lead to savings for the NHS from about 102 to 204 million € compared to SOC.ConclusionsOur study showed that FeNO testing strategy may improve the management of asthmatic patients leading to significant savings for the NHS.

Value of Fractional Exhaled Nitric Oxide in Diagnosing Mild Asthma Responsive to Inhaled Corticosteroids.

Mild asthma is often characterized by normal spirometric values and a negative bronchodilation test (BDT), which makes accurate diagnosis challenging. The aim of our study was to evaluate the diagnostic accuracy of fractional exhaled nitric oxide (FeNO) in mild asthma. In adults with symptoms suggestive of asthma and normal spirometry values, BDT, FeNO, BPT and skin prick testing were performed. Patients with positive BPT started inhaled corticosteroid (ICS) therapy. Those with positive response to ICS were considered asthmatics. There were 142 asthmatics and 140 non-asthmatics. No significant difference was found in BDT between the groups, p = 0.233. Median FeNO levels were significantly higher in the asthma group (49.5 ppb) than in the non-asthma group (23 ppb), p < 0.001. BPT was positive in 145 (51.42%) and negative in 137 (48.58%) patients. Positive response to ICS treatment was recorded in 142/145 (97.9%) patients. In diagnosing asthma, FeNO ≥ 25 ppb had a sensitivity of 75.4% and specificity of 47.9%. FeNO has insufficient sensitivity and specificity in mild asthma and the application of BPT is often necessary to establish an accurate diagnosis.

Implementing Spirometry and Fractional Exhaled Nitric Oxide Testing in Childhood Asthma Management in UK Primary Care: An Observational Study to Examine Training and Implementation Cost and Impact on Patient’s Health Use and Outcome

National Asthma Guidelines are important to implement in the primary care setting to provide standardized and improved asthma care. This study was designed to evaluate the implementation and clinical outcomes related to the delivery of spirometry and fractional exhaled nitric oxide (FeNO) testing for children with diagnosed or suspected asthma in the primary care setting.The study included 27 clinical staff from 10 general practices and 612 children with asthma ages 5 to 16 years in a prospective observational cohort in the United Kingdom. Children with asthma were defined as those with the diagnosis of asthma or those suspected to have asthma who were prescribed asthma medications in the last 12 months.Training materials on spirometry and FeNO tests were developed and taught to 27 clinical staff to implement for the study patients. The cost of implementation was estimated based on time, cost of resources, and standard costs of care in the UK-based system. The study then compared this invested cost to the benefits, such as decreased unplanned healthcare utilization and the amount of oral corticosteroids used. Participants were given the 3 questionnaires: Asthma Control Test (ACT), mini Pediatric Asthma Quality of Life Questionnaire (mini PAQLQ), and Child's Health Utility 9D (CHU9D), which measure asthma control, asthmatic quality of life, and general health, respectively, at the time of review and 6 months later to measure the benefits.The overall cost for material development, training time, and purchase of equipment was about £58 317 ($75 171 US dollars). The study equipment included 2 spirometers and 2 FeNO machines that rotated between clinics; however, the spirometry machines were donated and therefore, did not contribute to the total costs. Healthcare utilization was reduced by a total of £26 064 ($33 596) or £43 ($55) per child in the subsequent 6 months after the asthma review. Following the asthma assessments, there was an increase in daily inhaled corticosteroids prescribed, and fewer children required prescribed oral corticosteroids. There was no significant difference in the number of short-acting β-agonist inhalers prescribed. Of the 612 children, only 226 however completed their follow-up surveys at 6 months. ACT scores for ages 5 and up improved significantly. The mini PAQLQ was not statistically significant and the CHU9D decreased significantly at follow-up.Overall, the cost to train the staff and implement spirometry and FeNO measurement practices in the primary care clinic was £95 per child ($123). The potential healthcare dollar savings and benefits demonstrated with improved outcomes are significant and worth consideration and investment.This study from the UK demonstrates how a $150 investment per asthmatic child could lead to fewer emergency department visits, better controller medication compliance, fewer oral steroids, and better healthcare dollar utilization overall. With training and implementation of asthma education using objective asthma data at the primary care provider level, these improved asthma outcomes can be achieved. A similar study based on the most recent EPR-4 guidelines and the American medical system would be beneficial to assess the translation and replication of cost-benefit analysis in the US healthcare system.URL: www.pediatrics.org/cgi/doi/10.1542/peds.10.1136.archdischild-2020-319310

Fractional Exhaled Nitric Oxide Testing: Change in Clinical Management of Asthma, or Chronic Obstructive Pulmonary

Asthma and chronic obstructive pulmonary disease (COPD) are common airway inflammatory conditions that can present in isolation or a combination known as asthma-chronic obstructive pulmonary disease overlap syndrome (ACOS). Due to similarities in clinical presentation, differentiating these conditions can be challenging. Fractional exhaled nitric oxide (FeNO) is an endogenous molecule that can be elevated in patients with airway inflammation, particularly asthma. The purpose of this study was to determine if FeNO levels can be used to change pharmacologic management (addition, in patients presenting with asthma, COPD, and ACOS. A retrospective chart review of 250 patients underwent FeNO testing; 93 patients were included in the final analysis with their FeNO levels and medications. Out of 76 patients, 34 were prescribed medications of interest (inhaled corticosteroids (ICS), Inhaled corticosteroids - long-acting beta-agonists (ICS-LABA), anticholinergics (AC) monotherapy or combination therapy). After the FeNO testing, the number of patients on ICS therapy doubled (8 to 16), and the number of patients on ICS -LABA increased by 69.2%. Lastly, the number of patients not on medication of interest, 57.1%, ended up on one after FeNO testing. Our results support the utility of FeNO as a viable test to manage patients with obstructive lung disease.

Levels of eicosanoids in nasal secretions associated with nasal polyp severity in chronic rhinosinusitis

Severe nasal polyposis and mucosal inflammation, in patients with chronic rhinosinusitis (CRS) may include a dysregulated eicosanoid profile, but a clinical role for eicosanoids in CRS with nasal polyps (NP; CRSwNP) remains to be elucidated. This study focused on assessing levels and clinical implications of inflammatory mediators in nasal secretions and urine from patients with different NP severity or Aspirin Exacerbated Respiratory Disease (AERD). Levels of leukotrienes E4 and B4, prostaglandins D2 and E2 as well as 15(S)-hydroxyeicosatetraenoic acid were measured with enzyme immunoassays and cytokines with magnetic bead immunoassays. Patients with CRSwNP were subdivided based on NP score; CRSwNP-low (NP score ≤ 4, n = 11) or CRSwNP-high (NP score ≥ 5, n = 32) and compared to CRS without polyps (CRSsNP, n = 12), CRSwNP-AERD (n = 11) and individuals without CRS (n = 25). Smell test score, fractional exhaled nitric oxide (FeNO), blood eosinophils and Sinonasal outcome test-22 were assessed as clinical markers. Leukotriene E4, prostaglandin D2 and 15(S)-hydroxyeicosatetraenoic acid in nasal secretions correlated with NP score. Nasal leukotriene E4 also correlated with FeNO and smell test score, with highest levels found in CRSwNP-AERD. Levels of prostaglandin D2 in nasal secretion as well as urinary levels of the prostaglandin D2 metabolite 11β-prostaglandin F2α differed between CRSNP-high and CRSwNP-low. Urinary 11β-prostaglandin F2α was associated with asthma comorbidity whereas a similar association with prostaglandin D2 in nasal secretions was not observed. In conclusion, subdividing patients based on NP severity in combination with analysis of eicosanoids in non-invasively collected nasal secretions, may have clinical implications when assessing CRS disease severity.

Short- and medium-term effect of inhaled corticosteroids on exhaled breath biomarkers in severe asthma

Inhaled corticosteroids (ICS) are the mainstay of therapy in asthma, but benefits vary due to disease heterogeneity. Steroid insensitivity is a particular problem in severe asthma, where patients may require systemic corticosteroids and/or biologics. Biomarkers sensitive to ICS over a short period of time could inform earlier and more personalised treatment choices. To investigate how exhaled breath biomarkers change over two-hours and one-week following monitored ICS dosing in severe asthma patients with evidence of uncontrolled airway inflammation. Patients with severe asthma and elevated fractional exhaled nitric oxide (FeNO) (⩾45 ppb, indicative of active airway inflammation) were recruited. Exhaled breath biomarkers were evaluated using (FeNO), exhaled breath temperature (EBT), particles in exhaled air (PExA) and volatile organic compounds (VOCs). Samples were collected over 2 h following observed inhalation of 1000 mcg fluticasone propionate, and at a second visit 1 week after taking the same dose daily via an inhaler monitoring device that recorded correct actuation and inhalation. Changes in parameters over 2 h were analysed by the Friedman test and 1 week by Wilcoxon’s test (p-value for significance set at 0.05; for VOCs false discovery rate q of 0.1 by Benjamini–Hochberg method applied). 17 participants (9 male) were recruited, but three could not complete PExA and two FeNO testing, as they were unable to comply with the necessary technique; complete datasets were available from 12 (9 male) with median (interquartile range) age 45 (36–59) yrs. EBT (p < 0.05) and levels of six VOCs (q < 0.1) fell over the 2 h after high dose ICS; there were no changes in FeNO or PExA. After one week of using high dose ICS, there were falls in FeNO, EBT and two VOCs (p < 0.05), but no changes in PExA. Reduction in EBT over the short and medium term after high dose ICS may reflect airway vascular changes, and this, together with the observed changes in exhaled VOCs, merits further investigation as potential markers of ICS use and effectiveness.

Understanding the Updates in the Asthma Guidelines.

Asthma is a chronic inflammatory lung disease that affects millions of Americans, with variable symptoms of bronchospasm and obstruction among individuals over time. The National Heart, Lung, and Blood Institute (NHLBI) published the 2020 Focused Updates to the Asthma Management Guidelines based on the latest research since the 2007 Expert Panel Report-3 (EPR-3). The following article reviews the 21 new recommendations on the six core topics in asthma: use of intermittent inhaled corticosteroids, long-acting muscarinic antagonist therapy, use of the fractional exhaled nitric oxide test in asthma diagnosis and monitoring, indoor allergen mitigation, immunotherapy, and bronchial thermoplasty. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to rate recommendations as strong or conditional based on the evidence. The recommendations were based on systematic reviews of the literature and focused on patient-centered critical outcomes of asthma exacerbations, asthma control, and asthma-related quality of life. Understanding the recommendations with consideration of individual values through shared decision-making may improve asthma outcomes.

Measurement and Interpretation of Fractional Exhaled Nitric Oxide

Nitric oxide is produced by the human lungs and increases in response to type 2 inflammation. The level of fractional exhaled nitric oxide (FeNO) may reflect type 2 inflammation in the airways, which is related to eosinophilic inflammation and treatment responsiveness to corticosteroids. The FeNO test is a non-invasive, simple, and safe point-of-care test to evaluate airway inflammation. It has been standardized for clinical use and has been widely utilized in daily medical practice. However, various intrinsic and extrinsic factors can affect FeNO levels, and understanding and controlling such factors will improve the utility of this measure. The FeNO test can be used to confirm an asthma diagnosis, predict treatment responses to corticosteroids, and guide inhaled corticosteroid therapy for asthma treatment.

Overview of the Updates for the Management of Asthma Guidelines.

Asthma is a common diagnosis for pediatric patients, and something frequently managed in the primary care setting. Due to the multitude of factors that affect asthma, obtaining good control of the disease can be difficult. Managing triggers, medications, and adherence are key to maintaining good asthma control and quality of life. The National Heart, Lung, and Blood Advisory Council has released new guidelines and recommendations to help assist in the management of asthma. The expert panel addressed several key areas and made recommendations based on the available data. Areas addressed were the use of intermittent inhaled corticosteroids, the use of long-acting muscarinic antagonist, allergen mitigation, fractional exhaled nitric oxide testing for asthma diagnosis and management, and immune modulation for asthma control. This article summarizes the key recommendations and changes to the guideline. [Pediatr Ann. 2022;51(4):e132-e135.].

Qualitative study on perceptions of use of Fractional Exhaled Nitric Oxide (FeNO) in asthma reviews

Current methods to assess asthma and guide inhaled corticosteroid (ICS) dose titration mainly centre on patient-reported symptoms and lung function assessments. However, these methods correlate only weakly with airway inflammation making them unreliable predictors of future exacerbations and ICS requirement. Fractional Exhaled Nitric Oxide (FeNO) is a simple non-invasive objective measure of airways inflammation used predominantly in specialist clinics. Previous qualitative studies have mainly focused on the acceptability of FeNO in secondary care and there is limited insight to support clinicians and patients using FeNO in primary care asthma reviews. This study aimed to explore adult patient with asthma and primary care health care professional (HCP) views on introducing FeNO as part of routine asthma reviews. Twenty-three health care professionals and 22 patients were interviewed over the phone or online. Both groups reported that current asthma reviews are often seen as tick-box exercises and that introducing the FeNO test would make reviews more tailored to the individual patient, rather than relying on subjective patient reports of asthma control. Adults with asthma also highlighted support more open communication and their understanding of asthma, as they desired to feel more engaged in decisions and conversations about their asthma. HCPs reported valuing patient education and empowerment over a paternalistic approach, when time and resources allow. They also recognised FeNO to provide an objective measure of inflammation that could support them in the education and empowerment of patients. FeNO was seen by both groups as a potentially valuable addition to current asthma reviews mainly led by nurses, both for increasing their understanding of current risk of exacerbation and also to provide more tailored and personalised asthma management to patients. Our findings highlighted the need for open and clear communication about how to interpret FeNO results.

Asthma diagnosis using patient-reported outcome measures and objective diagnostic tests: now and into the future.

The global prevalence of asthma continues to increase; however, asthma remains under-diagnosed and under-treated. This results in a significant burden on the healthcare system and preventable patient morbidity and mortality. Over-diagnosis of asthma based on clinical history alone also complicates patient management. This heightens the importance of a prompt and accurate asthma diagnosis. Therefore, a review of the literature was performed regarding both objective diagnostic testing for asthma and using patient-reported outcome measures. The cornerstone of asthma diagnosis remains spirometry with testing for bronchodilator reversibility testing for pediatric and adult populations. This test may need to be repeated at multiple time points due to its low sensitivity. Peak flow measurement, fractional exhaled nitric oxide testing, and allergy testing are useful adjuncts to the diagnosis and phenotyping of asthma. Bronchoprovocation testing is reserved for people with high clinical suspicion for asthma, but negative spirometry. Novel noninvasive testing modalities may play a diagnostic role in the future. The advent of remote digital health monitoring technology has resulted in revisiting patient-reported outcome measures for the diagnosis and monitoring of asthma. Overall, improved diagnostic tools for asthma are crucial for earlier recognition and treatment of the disease and improved patient care outcomes worldwide.

FeNO in Asthma.

Asthma is a common disease affecting 350 million people worldwide, which is characterized by airways inflammation and hyperreactivity. Historically diagnosis and treatment have been mainly based on symptoms, which have the potential to result in misdiagnosis and inappropriate treatment. Nitric oxide (NO) is exhaled in human breath and is a marker of airways inflammation. Levels of NO are increased in the exhaled breath of patients with type 2 asthma and fractional exhaled nitric oxide (FeNO) provides an objective biomarker of airway inflammation. FeNO testing is an accessible, noninvasive, and easy-to-use test. Cut-off values have been established by the American Thoracic Society (ATS), the Global Initiative for Asthma (GINA), and the National Institute for Health and Care Excellence (NICE) but vary between guidance. FeNO levels have been shown to be predictive of blood and sputum eosinophil levels but should not be used in isolation and current guidance emphasizes the importance of incorporating clinical symptoms and testing when utilizing FeNO results. The inclusion of FeNO testing can increase diagnostic accuracy of asthma, while high levels in asthmatic patients can help predict response to inhaled corticosteroids (ICS) and suppression of levels with ICS to monitor adherence. FeNO levels are also a predictor of asthma risk with increased exacerbation rates and accelerated decline in lung function associated with high levels as well as having an emerging role in predicting response to some biologic therapies in severe asthma. FeNO testing is cost-effective and has been shown, when combined with clinical assessment, to improve asthma management.

Use of Fractional Exhaled Nitric Oxide to Guide the Treatment of Asthma: An Official American Thoracic Society Clinical Practice Guideline.

Background: The fractional exhaled nitric oxide (FENO) test is a point-of-care test that is used in the assessment of asthma.Objective: To provide evidence-based clinical guidance on whether FENO testing is indicated to optimize asthma treatment in patients with asthma in whom treatment is being considered.Methods: An international, multidisciplinary panel of experts was convened to form a consensus document regarding a single question relevant to the use of FENO. The question was selected from three potential questions based on the greatest perceived impact on clinical practice and the unmet need for evidence-based answers related to this question. The panel performed systematic reviews of published randomized controlled trials between 2004 and 2019 and followed the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) evidence-to-decision framework to develop recommendations. All panel members evaluated and approved the recommendations.Main Results: After considering the overall low quality of the evidence, the panel made a conditional recommendation for FENO-based care. In patients with asthma in whom treatment is being considered, we suggest that FENO is beneficial and should be used in addition to usual care. This judgment is based on a balance of effects that probably favors the intervention; the moderate costs and availability of resources, which probably favors the intervention; and the perceived acceptability and feasibility of the intervention in daily practice.Conclusions: Clinicians should consider this recommendation to measure FENO in patients with asthma in whom treatment is being considered based on current best available evidence.

Decreased nasal nitric oxide levels: A potential marker of decreased olfactory discrimination in chronic rhinosinusitis.

AbstractObjectiveThis study aimed to investigate the association of nasal nitric oxide and olfactory function.MethodA cross-sectional study was performed in 117 adults, including 91 patients with chronic rhinosinusitis and 26 healthy controls. Scores on the 22-item Sino-Nasal Outcomes Test, Lund-Mackay scale and Lund-Kennedy scale were recorded to assess severity of disease. All participants were screened for common inhaled and food allergens. Nasal nitric oxide and fractional exhaled nitric oxide testing, acoustic rhinometry and anterior rhinomanometry testing were performed to measure nasal function. The validated Sniffin’ Sticks test battery was used to assess olfactory function.ResultsHigher nasal nitric oxide was an independent protective factor for odour discrimination and odour threshold in participants with chronic rhinosinusitis after adjusting for age, gender, drinking, smoking, 22-item Sino-Nasal Outcomes Test, Lund-Mackay score, Lund-Kennedy score, immunoglobulin E and the second minimal cross-sectional area by acoustic rhinometry. Nasal nitric oxide also showed high discrimination in predicting impaired odour discrimination. In addition, nasal nitric oxide was lower in older participants, those with higher Lund-Mackay or Lund-Kennedy scores and higher with elevated total serum immunoglobulin E concentrations above a threshold of 0.35 kU/l.ConclusionHigher nasal nitric oxide is associated with better odour discrimination in chronic rhinosinusitis and is modulated by age, degree of allergy and severity of chronic rhinosinusitis.

The Utility of Serum IL-1β and CRP Together with Fractional Exhaled Nitric Oxide in the Diagnosis of Asthma in Adults

Background: Bronchial asthma (BrA), recognized lately as an umbrella, covers various subtypes rather than only one disease. Asthma is a chronic inflammation of the airways, in which cytokines could play a crucial role in its pathogenesis. Hence, labors to progress noninvasive markers for asthma had centered through this era. Presently, the fractional exhaled nitric oxide (FeNO), serum C-reactive protein (CRP), and interleukin levels are emerging analytical biomarkers in this field. FeNO is a noninvasive and practical tool even in mild asthma. This study aimed to evaluate the utility of serum IL-1β and CRP together with fractional exhaled nitric oxide in the diagnosis of adult bronchial asthma. Method: The study was a case control, including 150-patients and 100-healthy controls. FeNO tests, measurements of plasma levels IL-1β and HS-CRP had undertaken for all the participants. The statistical data had examined by SPSS (V/27) for Windows. Descriptive data of the variables had compatibly used. A significance lower than or identical to 0.05 had intended. ROC curve examination of FeNO tests, IL-1β, and HS-CRP, to predict asthma from healthy control had applied. Results: there was a significant difference in the FeNo test, HS-CRP levels, and BMI, while no significant difference in all other variables between the groups. The FeNo results correlate positively, though not significantly, with the levels of IL-1β in asthmatic patients (&gt; 0.05). There was a nonsignificant negative correlation between the FeNo results with the level of HSCRP. The accuracy, sensitivity, and specificity of the IL-1β to distinguish asthma were 68.6% and 58% at 95% CI [0.41-0.745], respectively, which was not significant (p&gt;0.05). However, ROC analysis of HS-CRP revealed predictability for asthma patients (p-0.000), with higher accuracy, sensitivity, and specificity: 89.9%, and 68.1% at 95% CI [0.820-0.979], respectively. The FeNo tests revealed highly significant (0.000), high sensitivity, and specific (91% for both) with high 95% CI [0.938-1.000] predictability for asthma. Conclusion: The utility of circulating HS-CRP is more valuable than IL-1β when combined with fractional exhaled nitric oxide in the diagnosis of asthma. Novel biomarkers could improve the precision of this field.