Performance of a new hand-held device for exhaled nitric oxide measurement in adults and children

Exhaled Biomarkers for Point-of-Care Diagnosis: Recent Advances and New Challenges in Breathomics

Cancers, chronic diseases and respiratory infections are major causes of mortality and present diagnostic and therapeutic challenges for health care. There is an unmet medical need for non-invasive, easy-to-use biomarkers for the early diagnosis, phenotyping, predicting and monitoring of the therapeutic responses of these disorders. Exhaled breath sampling is an attractive choice that has gained attention in recent years. Exhaled nitric oxide measurement used as a predictive biomarker of the response to anti-eosinophil therapy in severe asthma has paved the way for other exhaled breath biomarkers. Advances in laser and nanosensor technologies and spectrometry together with widespread use of algorithms and artificial intelligence have facilitated research on volatile organic compounds and artificial olfaction systems to develop new exhaled biomarkers. We aim to provide an overview of the recent advances in and challenges of exhaled biomarker measurements with an emphasis on the applicability of their measurement as a non-invasive, point-of-care diagnostic and monitoring tool.

Dispositivos de medición de FENO

The use of devices for measuring the exhaled fraction of nitric oxide has proven to be very useful, especially in the diagnosis of asthma, prediction of response to corticosteroids, risk of exacerbations or compliance with treatment, among others, and their use is recommended by important clinical practice guidelines. In recent years we have witnessed a proliferation of options on the market with different characteristics. To help in choosing a device that suits the needs of the professionals involved in the management of asthma, this review presents some of the important characteristics of the most common devices. In addition, the existing comparative and pharmacoeconomic studies are analyzed so that professionals can make the choice of device guided by the most current evidence.

Blood Eosinophils and Exhaled Nitric Oxide: Surrogate Biomarkers of Airway Eosinophilia in Stable COPD and Exacerbation

In recent years, tremendous efforts have been devoted to characterizing the inflammatory processes in chronic obstructive pulmonary disease (COPD) in order to provide more personalized treatment for COPD patients. While it has proved difficult to identify COPD-specific inflammatory pathways, the distinction between eosinophilic and non-eosinophilic airway inflammation has gained clinical relevance. Evidence has shown that sputum eosinophil counts are increased in a subset of COPD patients and that these patients are more responsive to oral or inhaled corticosteroid therapy. Due to feasibility issues associated with sputum cell profiling in daily clinical practice, peripheral blood eosinophil counts and fractional exhaled nitric oxide levels have been evaluated as surrogate biomarkers for assessing the extent of airway eosinophilia in COPD patients, both in stable disease and acute exacerbations. The diagnostic value of these markers is not equivalent and depends heavily on the patient’s condition at the time of sample collection. Additionally, the sensitivity and specificity of these tests may be influenced by the patient’s maintenance treatment. Overall, eosinophilic COPD may represent a distinct disease phenotype that needs to be further investigated in terms of prognosis and treatment outcomes.

Tiotropium Add-On and Treatable Traits in Asthma-COPD Overlap: A Real-World Pilot Study

Purpose

The 'treatable traits' strategy for patients with chronic inflammatory airway diseases, especially asthma and chronic obstructive pulmonary disease (COPD), is a focus of interest, because it implements precision and personalized medicine. Asthma-COPD overlap (ACO), a phenotype involving both asthma and COPD, is an important disease entity because patients with ACO have significantly worse outcomes, conferring greater economical and social burdens. Some guidelines for ACO recommend add-on therapy of long-acting muscarinic antagonists to inhaled corticosteroids and long-acting β2 agonists. However, this approach is based on extrapolation from patients with asthma or COPD alone. Consequently, a 'treatable traits' approach suitable for ACO remains obscure.

Methods

A 12-week open-label cross-over pilot study was conducted in patients with ACO to investigate the effect of tiotropium bromide (TIO) 5 µg/day add-on therapy to fluticasone propionate/formoterol fumarate (FP/FM) 500/20 µg/day compared with FP/FM 500/20 µg/day alone. A 4-week run-in period and two 4-week treatment periods were included.

Results

A total of 18 male patients with stable ACO participated in this pilot study. All patients were ex-smokers. Mean values ± standard deviation (SD) for forced expiratory volume in 1 second (FEV1) were 1.21 ± 0.49 L after the run-in period, 1.20 ± 0.51 L after the FP/FM combination therapy period, and 1.30 ± 0.48 L after the TIO add-on therapy to FP/FM period. FEV1 values after the TIO add-on therapy FP/FM period were significantly higher than those after the run-in period (p < 0.01).

Conclusion

TIO add-on therapy to FP/FM in patients with ACO, considered difficult to treat because of the presence of both asthma and COPD, resulted in improvements in lung function parameters in this real-world pilot study, indicating the potential value of TIO add-on therapy as a "treatable traits" option for standard treatment for ACO.

Contributions of asthma, rhinitis and IgE to exhaled nitric oxide in adolescents

Exhaled nitric oxide fraction (F_eNO) is an indicator of allergic airway inflammation. However, it is unknown how asthma, allergic rhinitis (AR) and allergic sensitisation relate to F_eNO, particularly among adolescents and in overlapping conditions. We sought to determine the associations between asthma, AR, and aeroallergen immunoglobulin (Ig)E and F_eNO in adolescents.

We measured F_eNO among 929 adolescents (aged 11–16 years) in Project Viva, an unselected prebirth cohort in Massachusetts, USA. We defined asthma as ever asthma physician diagnosis plus wheezing in the past year or taking asthma medications in the past month, AR as a physician diagnosis of hay fever or AR, and aeroallergen IgE as any IgE >0.35 IU·mL⁻¹ among 592 participants who provided blood samples. We examined associations of asthma, AR and IgE with percent difference in F_eNO in linear regression models adjusted for sex, race/ethnicity, age and height, maternal education and smoking during pregnancy, and household/neighbourhood demographics.

Asthma (14%) was associated with 97% higher F_eNO (95% CI 70–128%), AR (21%) with 45% higher F_eNO (95% CI 28–65%), and aeroallergen IgE (58%) with 102% higher F_eNO (95% CI 80–126%) compared to those without each condition, respectively. In the absence of asthma or AR, aeroallergen IgE was associated with 75% higher F_eNO (95% CI 52–101), while asthma and AR were not associated with F_eNO in the absence of IgE.

The link between asthma and AR with F_eNO is limited to those with IgE-mediated phenotypes. F_eNO may be elevated in those with allergic sensitisation alone, even in the absence of asthma or AR.

While asthma, allergic rhinitis (AR) and allergic sensitisation are associated with higher F_ENO, asthma and AR in the absence of aeroallergen IgE are not associated with F_ENO. When elevated in asthma or AR, F_ENO suggests allergic sensitisation.https://bit.ly/3bGgr0r

Subcortical gray matter volumes in asthma: associations with asthma duration, control, and anxiety

Asthma as a chronic inflammatory disease can be expected to affect central nervous system structures but little is known about subcortical structures in asthma and their potential association with illness-specific outcomes and anxiety. A total of 40 young adults (20 with asthma and 20 gender- and age-matched controls) underwent high-resolution T1-weighted MRI scan, viewed short distressing film clips, and filled in questionnaires about anxious and depressed mood, as well as asthma history, control, and catastrophizing thoughts about asthma, for those with asthma. The structural scans were processed in FSL's FIRST program to delineate subcortical structures of interest: amygdala, hippocampus, putamen, pallidum, caudate nucleus, nucleus accumbens, and thalamus. Findings showed no general reduction in subcortical gray matter volumes in asthma compared to controls. Asthma duration, asthma control, and catastrophizing of asthma and asthma attacks were negatively associated with volumes of putamen and pallidum, and to a weaker extent thalamus and amygdala, while controlling for gender, age, and corticosteroid inhaler use. In addition, stronger anxiety in response to distressing films was associated with lower volume of the pallidum, whereas general anxious and depressed mood was unrelated to subcortical structures. Thus, although there are no subcortical structural differences between young adults with asthma and healthy controls, longer asthma history, suboptimal management, and illness-related anxiety are reflected in lower gray matter volumes of subcortical structures, further emphasizing the importance of maintaining optimal asthma control.

Measurement of Fractional Exhaled Nitric Oxide in Adults: Comparison of Two Different Analyzers (NIOX VERO and NObreath)

BACKGROUND

Fractional exhaled nitric oxide (FeNO) is a non-invasive marker for eosinophilic airway inflammation and a good predictor of response to corticosteroids. There is a need for a reliable and accurate measurement method, as FeNO measurements have been widely used in clinical practice. Our study aimed to compare two FeNO analyzers and derive a conversion equation for FeNO measurements in adults.

METHODS

We included 99 participants who had chief complaints of chronic cough and difficulty in breathing. The participants underwent concurrent FeNO measurement using NIOX VERO (Circassia AB) and NObreath (Bedfont). We compared the values of the two devices and analyzed their correlation and agreement. We then formulated an equation to convert FeNO values measured by NObreath into those obtained by NIOX VERO.

RESULTS

The mean age of the participants was 51.2±17.1 years, with a female predominance (58.6%). Approximately 60% of the participants had asthma. The FeNO level measured by NIOX VERO (median, 27; interquartile range [IQR], 15-45) was significantly lower than that measured by NObreath (median, 38; IQR, 22-58; p<0.001). There was a strong positive correlation between the two devices (r=0.779, p<0.001). Additionally, Bland-Altman plots and intraclass correlation coefficient demonstrated a good agreement. Using linear regression, we derived the following conversion equation: natural log (Ln) (NObreath)=0.728×Ln (NIOX VERO)+1.244.

CONCLUSION

The FeNO values of NIOX VERO and NObreath were in good agreement and had positive correlations. Our proposed conversion equation could help assess the accuracy of the two analyzers.

Personalised exhaled nitric oxygen fraction (F ENO)-driven asthma management in primary care: a F ENO subgroup analysis of the ACCURATE trial

Background

The aim of this study was to identify patients who benefit most from exhaled nitric oxide fraction (F_ENO)-driven asthma management in primary care, based on prespecified subgroups with different levels of F_ENO.

Methods

We used data from 179 adults with asthma from a 12-month primary care randomised controlled trial with 3-monthly assessments of F_ENO, asthma control, medication usage, costs of medication, severe asthma exacerbations and quality of life. In the original study, patients were randomised to either a symptom-driven treatment strategy (controlled asthma (Ca) strategy) or a F_ENO+symptom-driven strategy (FCa). In both groups, patients were categorised by their baseline level of F_ENO as low (<25 ppb), intermediate (25–50 ppb) and high (>50 ppb). At 12 months, we compared, for each prespecified F_ENO subgroup, asthma control, asthma-related quality of life, medication usage, and costs of medication between the Ca and FCa strategy.

Results

We found a difference between the Ca and FCa strategy for the mean dosage of beclomethasone strategy of 223 µg (95% CI 6–439), p=0.04) and for the total costs of asthma medication a mean reduction of US$159 (95% CI US$33–285), p=0.03) in patients with a low baseline F_ENO level. No differences were found for asthma control, severe asthma exacerbations and asthma-related quality of life in patients with a low baseline F_ENO level. Furthermore, in patients with intermediate or high level of F_ENO, no differences were found.

Conclusions

In primary care, F_ENO-driven asthma management is effective in patients with a low F_ENO level, for whom it is possible to down-titrate medication, while preserving asthma control and quality of life.

In primary care, F_ENO-driven asthma management is effective in patients with a low F_ENO, for whom it is possible to down-titrate medication while preserving asthma control and quality of lifehttps://bit.ly/2wC25N7d

Clinical Features of Chronic Obstructive Pulmonary Disease with High Fractional Exhaled Nitric Oxide

Background

The fractional exhaled nitric oxide (FENO) test is useful in asthma patients. However, a few studies on its usefulness in chronic obstructive pulmonary disease (COPD) patients have been reported. We analyzed the FENO level distribution and clinical characteristics according to the FENO level in COPD patients.

Methods

From December 2014 to June 2019, COPD patients who underwent pulmonary function and FENO tests at Chonnam National University Hospital were retrospectively evaluated for FENO, comorbidities, asthma history, blood eosinophil, and pulmonary function test. The high FENO group was defined as those with FENO level>25 parts per billion (ppb).

Results

A total of 849 COPD patients (mean age, 70.3±9.4 years) were included. The mean forced expiratory volume at 1 second was 66.5±21.7% and the mean FENO level was 24.3±20.5 ppb. Patients with FENO ≤25 ppb were 572 (67.4%) and those with FENO >25 ppb were 277 (32.6%). Blood eosinophil percentage was significantly higher (4.2±4.8 vs. 2.7±2.5, p<0.001) in patients with the high FENO group than the low FENO group. The high FENO group revealed a significantly higher frequency of patients with blood eosinophil percentage >3% (46.9% vs. 34.8%, p=0.001) and asthma history (25.6% vs. 8.6%, p<0.001) than the lower FENO group. Asthma history, blood eosinophil percentage >3%, and positive bronchodilator response (BDR) were independent risk factors for the high FENO level (adjusted odds ratio [aOR], 3.85; p<0.001; aOR, 1.46; p=0.017; and aOR, 1.57, p=0.034, respectively) in the multivariable analysis.

Conclusion

The FENO level distribution varied in COPD patients and the mean FENO value was slightly elevated. Asthma history, eosinophil percent, and positive BDR were independent risk factors for the high FENO level.

Triple Therapy with Budesonide/Glycopyrrolate/Formoterol Fumarate Improves Inspiratory Capacity in Patients with Asthma-Chronic Obstructive Pulmonary Disease Overlap

Purpose

Asthma-chronic obstructive pulmonary disease overlap (ACO), characterized by airway limitation, is an important condition with high incidence and mortality. Although some guidelines recommend triple therapy with inhaled corticosteroids/long-acting muscarinic antagonists/long-acting β2 agonists, this treatment approach is based on the extrapolation of data from studies of asthma or chronic obstructive pulmonary disease (COPD) alone.

Methods

A 12-week, randomized, open-label cross-over pilot study was conducted in 19 patients with ACO to investigate the effect of triple therapy with glycopyrrolate (GLY) 50 µg/day on budesonide/formoterol fumarate (BUD/FORM) 640/18 µg/day. The study period included a 4-week wash-out, 4-week run-in, and 4-week treatment period. Respiratory function tests, fractional exhaled nitric oxide (FeNO), a COPD assessment test (CAT) and an asthma control questionnaire (ACQ) were carried out 0, 4, and 8 weeks after randomization.

Results

A total of 19 patients with stable ACO (19 males and no females) with a mean age of 70.7 ± 7.6 years (± standard deviation, SD; range 55-83 years) participated in this study. All patients were ex-smokers with a smoking history of 63.1 ± 41.1 pack-years (± SD). Mean values for inspiratory capacity (IC), an index of hyperinflation of the lung that causes exertional dyspnea and reduced exercise, were 1.93 L (± 0.47 L) after the run-in, 1.85 L (± 0.51 L) after the BUD/FORM dual therapy period and 2.11 L (± 0.58 L) after the BUD/GLY/FORM triple therapy period. IC values after the BUD/GLY/FORM triple therapy were significantly higher than those after the run-in (p < 0.02). FeNO values, ACQ, and CAT scores were not significantly different among the run-in, wash-out, and triple-therapy periods.

Conclusion

The present pilot study showed that triple therapy with BUD/GLY/FORM results in an improvement in lung function parameters including IC, indicating the potential value of triple therapy as standard treatment for ACO.

Genotype and phenotype evaluation of patients with primary ciliary dyskinesia: First results from Turkey

BACKGROUND AND OBJECTIVE

Primary ciliary dyskinesia (PCD) is a rare and genetically heterogeneous disease and the severity of the disease related with genetic analysis has been described in some previous studies. The main aim of our study was to describe the clinical characteristics and laboratory findings of patients with genetically diagnosed PCD and to investigate the correlation between clinical, radiologic, and laboratory findings and genetic analyses of these patients.

METHOD

This is a cohort study in which we analyzed the clinical characteristics, laboratory findings, and genetic results of 46 patients with genetically diagnosed PCD through whole-exome sequencing at our single center from a total of 265 patients with PCD within a 5-year period.

RESULTS

Genetic analysis revealed pathogenic variants in DNAH5 (n = 12 individuals, 12 families), CCDC40 (n = 9 individuals, six families), RSPH4A (n = 5 individuals, three families), DNAH11 (n = 4 individuals, four families), HYDIN (n = 5 individuals, five families), CCNO (n = 4 individuals, four families), DNAI1 (n = 2 individuals, one family), ARMC4 (n = 2 individuals, two families), TTC25 (n = 1), DNAH1 (n = 1), and CCDC39 (n = 1) genes. Although not statistically significant, the age at diagnosis was lower (median: 3 years; range, 6 months-4 years) in patients with CCNO pathogenic variants due to the early reporting of symptoms, and the median body mass index (BMI) and BMI z scores were lower in patients at 18.7 and 16 kg/m² , and -0.78 and -1.2 with CCDC40 and CCNO pathogenic variants, respectively. The median forced expiratory flow in 1 second (FEV1%), forced vital capacity (FVC%), and forced expiratory flow (FEF)25-75% were 53%, 64%, and 28%, respectively; these parameters were also lower in the CCDC40 group than in the other groups. There was no significant correlation between the genetic results and symptoms, radiologic findings, and microbiologic data of patients with PCD.

CONCLUSION

In PCD, there was significant heterogeneity of lung disease, patients who had pathogenic variants in CCNO presented earlier, and those with CCDC40 and CCNO had worse lung disease, and poorer nutritional status compared with the other subgroups. We hope that whole genotype-phenotype and clinical relationships will be identified in PCD.

The clinical usefulness of a new hand-held device for fractional exhaled nitric oxide measurement, NIOX VERO®, for diagnosing the etiology of cough

Cough is one of the most common symptoms seen in clinical practice, however the differential diagnosis is often difficult. The utility of fractional exhaled nitric oxide (FeNO) measurement in the differential diagnosis of the etiology of cough has been reported. NIOX VERO® (NOV) is a new hand-held device that will replace NIOX MINO®, but its diagnostic utility has not been fully elucidated in clinical practice. In this study, the performance of NOV for FeNO measurements was determined. We retrospectively analyzed 243 consecutive patients complaining cough. Among 243 patients, final diagnosis was cough variant asthma (CVA) in 74 (30.5%), bronchial asthma (BA) in 48 (19.8%), post-infectious cough (PIC) in 52 (21.4%), atopic chough (AC) in 24 (9.9%), gastroesophageal reflux disease (GERD) in 10 (4.1%), and Others in 35 (14.4%). FeNO values were significantly higher in CVA and BA as compared to PIC, AC, GERD, and Others. In the multivariate analysis, only FeNO value was identified as independent factors to discriminate CVA and non-CVA other than BA. These findings indicated that FeNO measured by using NOV could be used as a diagnostic marker of intractable cough, especially for the differential diagnosis of CVA from non-CVA. J. Med. Invest. 67 : 265-270, August, 2020.

Clinical precision, accuracy, number and durations of exhalations for a novel electrochemical monitor for exhaled nitric oxide

BACKGROUND

Exhaled nitric oxide (FeNO) is a validated marker of eosinophilic inflammation. Fenom Pro^TM is a novel FDA-cleared monitor for FeNO. The American Thoracic Guidelines from 2005 recommend at least 6 s exhalation for adults and in some cases up to 10 s, and 4 s for children, and that the average of the first two valid exhalations is taken as the FeNO value.

METHODS

Clinical precision, 6 versus 10 s exhalations, the first versus the average of the first two valid exhalation methods comparison were evaluated for Fenom Pro^TM, as well as a methods comparison to the NIOX VERO^® monitor.

RESULTS

The intent-to-treat population (n = 126) consisted of 83 adults, and 43 pediatric subjects with 16 subjects under 12 years of age. Clinical precision for 10 s exhalations on Fenom Pro^TM was excellent with a within-subject standard deviation (SD) range of 0.57-3.73 ppb and mean coefficient of variation (CV) range of 4.21% to 9.65%. The clinical precision for the separate adult and pediatric groups as well as for the 6 s exhalations were similar. The 10 and 6 s exhalation comparisons and one versus the average of two valid exhalations showed a high level of agreement. The Fenom Pro^TM and the NIOX VERO^® monitors also demonstrated a high level of agreement with the values from the latter slightly lower (mean bias of -3.2 ppb).

CONCLUSION

Fenom Pro^TM demonstrated eminently acceptable performance supporting its clinical utility. The data suggests that 6 s exhalations can be used in adults and children, and that one exhalation is adequate rather than obtaining the average of two exhalations on Fenom Pro^TM.

Clinical Utility Of The Exhaled Nitric Oxide (NO) Measurement With Portable Devices In The Management Of Allergic Airway Inflammation And Asthma

Nitric oxide (NO) is a potential bioactive gas produced continuously and constantly in the airways of healthy subjects. In allergic airway inflammation, the level of exhaled NO is usually increased and mediated by inducible nitric oxide synthase (iNOS) enzyme presenting in the epithelium and different inflammatory cells. The measurement of NO concentration in the airway is possible with portable devices which use an electroluminescence technique. In subjects with upper airway with allergic inflammation such as in allergic rhinitis, the measurement of nasal NO (nNO) may help to diagnose and manage the disease. In the lower airway, increased fractional exhaled NO (FENO) reflects directly the inflammatory process that occurs in the airways that are typically seen in asthma. It has been shown that there is a strong correlation between FENO levels and increased activity of airway inflammation mediated by immuno-allergic cells and mediators. Thus, FENO has higher specificity and sensitivity than other methods in diagnosing the severity of inflammation in asthmatic patients. Moreover, the correlation between increased FENO levels and a high risk of bronchial hyperresponsiveness has also been demonstrated. FENO is also a relevant biomarker to evaluate asthma status due to the change of its values occurring earlier than clinical manifestations and spirometry parameters. In addition, the measurement of FENO with portable devices helps to support the diagnosis of asthma, to follow-up the control of asthma and to personalize asthmatic patients for target treatment with biologic therapy. Therefore, measuring FENO with portable devices in the diagnosis and treatment of allergic airway inflammation, especially in asthma, is one of the most essential applications of NO biomarkers in exhaled breath.

Fractional exhaled nitric oxide as a potential biomarker for radiation pneumonitis in patients with non-small cell lung cancer: A pilot study

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Weekly FeNO during radiotherapy can be useful in predicting radiation pneumonitis.

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6 months of clinical follow-up is necessary to detect delayed radiation pneumonitis.

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Pulmonary function tests are not predictable for radiation pneumonitis.

Introduction

The aim of the study was to investigate repetitive fractional exhaled nitric oxide (FeNO) measurements during high-dose radiation therapy (HDRT) and to evaluate the use of FeNO to predict symptomatic radiation pneumonitis (RP) in patients being treated for non-small cell lung cancer (NSCLC).

Materials and methods

A total of 50 patients with NSCLC referred for HDRT were enrolled. FeNO was measured at baseline, weekly during HDRT, one month- and every third month after HDRT for a one-year follow-up period. The mean FeNO_{(visit 0-6)} was calculated using the arithmetic mean of the baseline and weekly measurements during HDRT. Patients with grade ≥ 2 of RP according to the Common Terminology Criteria for Adverse Events (CTCAE) were considered symptomatic.

Results

A total of 42 patients completed HDRT and weekly FeNO measurements. Grade ≥ 2 of RP was diagnosed in 24 (57%) patients. The mean FeNO_{(visit 0-6)} ± standard deviation in patients with and without RP was 15.0 ± 7.1 ppb (95%CI: 12.0–18.0) and 10.3 ± 3.4 ppb (95%CI: 8.6–11.9) respectively with significant differences between the groups (p = 0.0169, 95%CI: 2.3–2.6). The leave-one-out cross-validated cut-off value of the mean FeNO_{(visit 0-6)} ≥ 14.8 ppb was predictive of grade ≥ 2 RP with a specificity of 71% and a positive predictive value of 78%.

Conclusions

The mean FeNO_{(visit 0-6)} in patients with symptomatic RP after HDRT for NSCLC was significantly higher than in patients without RP and may serve as a potential biomarker for RP.

Exhaled nitric oxide in ethnically diverse high-altitude native populations: A comparative study

OBJECTIVES

Andean and Tibetan high-altitude natives exhibit a high concentration of nitric oxide (NO) in the lungs, suggesting that NO plays an adaptive role in offsetting hypobaric hypoxia. We examined the exhaled NO concentration as well as partial pressure of several additional high-altitude native populations in order to examine the possibility that this putative adaptive trait, that is, high exhaled NO, is universal.

METHODS

We recruited two geographically diverse highland native populations, Tawang Monpa (TM), a Tibetan derived population in North-Eastern India (n = 95, sampled at an altitude of ~3,200 m), and Peruvian Quechua from the highland Andes (n = 412). The latter included three distinct subgroups defined as those residing at altitude (Q-HAR, n = 110, sampled at 4,338 m), those born and residing at sea-level (Q-BSL, n = 152), and those born at altitude but migrant to sea-level (Q-M, n = 150). In addition, we recruited a referent sample of lowland natives of European ancestry from Syracuse, New York. Fraction of exhaled NO concentrations were measured using a NIOX NIMO following the protocol of the manufacturer.

RESULTS

Partial pressure of exhaled nitric oxide (PENO) was significantly lower (p < .05) in both high-altitude resident groups (TM = 6.2 ± 0.5 nmHg and Q-HAR = 5.8 ± 0.5 nmHg), as compared to the groups measured at sea level (USA = 14.6 ± 0.7 nmHg, Q-BSL = 18.9 ± 1.6 nmHg, and Q-M = 19.2 ± 1.7 nmHg). PENO was not significantly different between TM and Q-HAR (p < .05).

CONCLUSION

In contrast to previous work, we found lower PENO in populations at altitude (compared to sea-level) and no difference in PENO between Tibetan and Andean highland native populations. These results do not support the hypothesis that high nitric oxide in human lungs is a universal adaptive mechanism of highland native populations to offset hypobaric hypoxia.

Effect of triple therapy in patients with asthma-COPD overlap

OBJECTIVE

Asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) is of increasing interest because ACO patients have significantly worse outcomes, leading to greater social and economic burdens compared with asthma or COPD alone. Some guidelines for ACO recommend triple therapy with inhaled corticosteroids, long-acting β2 agonists, and long-acting muscarinic antagonists. However, this approach is based on extrapolating data from patients with asthma or COPD alone. Therapeutic studies for ACO have not previously been conducted.

MATERIALS AND METHODS

A 12-week, randomized, open-label cross-over pilot study was conducted in 17 ACO patients to evaluate the effect of umeclidinium (UMEC) 62.5 µg once-daily added to fluticasone furoate/vilanterol (FF/VI) 200/25 µg once-daily. A 4-week run-in, a first and a second 4-week treatment period were included. Respiratory function, respiratory impedance, fractional exhaled nitric oxide, COPD assessment test, and asthma control test scores were evaluated 0, 4, and 8 weeks after randomization.

RESULTS

Mean values of post-bronchodilator forced expiratory volume in 1 second as a percentage of the predicted value (%FEV1), after UMEC was added to FF/VI, were significantly higher than after the run-in (p < 0.01). Mean values of resonant frequency during inspiration (Fres), after UMEC was added to FF/VI, were significantly lower than after the run-in (p < 0.01).

CONCLUSION

Adding UMEC to FF/VI provides greater improvement in lung function, indicating that triple therapy is a suitable regular treatment for ACO.

Comparison of fractional exhaled nitric oxide levels measured by different analyzers produced by different manufacturers

Objective: Fractional exhaled nitric oxide (FeNO) is widely used as a biomarker of allergic airway inflammation. At present, both stationary chemiluminescence and portable electrochemical analyzers produced by different manufacturers are available. However, it remains debatable whether those analyzers are comparable to each other. We compare FeNO levels obtained by different analyzers.Methods: For the first study, 153 subjects were enrolled to compare differences in FeNO levels measured using three analyzers (NA623NP^®, NObreath^®, and NIOX MINO^®) which were produced by different manufacturers. For the second study, 30 subjects were recruited to compare FeNO levels obtained by the two analyzers (NIOX MINO^® and NIOX VERO^®) produced by the same manufacturer. FeNO was measured twice using each analyzer in random order.Results: FeNO levels obtained using the NIOX MINO^® and NObreath^® were more variable than those measured using the NA623NP^®. There were strong positive correlations in FeNO levels measured by the NA623NP^®, NIOX MINO^®, and NObreath^® (p < 0.001). The NA623NP^® and NIOX MINO^® provided the highest and lowest FeNO levels, respectively; whereas, those obtained by NObreath^® were intermediate. No significant differences were observed in FeNO levels obtained using the NIOX MINO^® and NIOX VERO^®.Conclusions: FeNO levels measured by the NIOX MINO^® and NIOX VERO^®, both of which were produced by the same manufacturer, have comparability. However, significant differences in FeNO levels exist when measured by analyzers manufactured by different manufacturers. This should be taken into account for FeNO measurement.

Measurement of Fractional Exhaled Nitric Oxide: Comparison of Three Different Analysers

BACKGROUND

Fractional exhaled nitric oxide (FeNO) is a surrogate marker for airway inflammation, supporting the diagnostic pathway and treatment decisions for asthma patients.

OBJECTIVES

Aim of this study was to compare the new analyser Vivatmo pro (Bosch, BV) with NIOX VERO (Circassia, CN) and CLD (Ecomedics, EC).

METHODS

In 100 asthmatics (median 53 years [range 20-87], 62% female, 86% on inhaled corticosteroids [mean 1,300 μg beclomethasone dipropionate or equivalent], 35% treated with biologics) 2 FeNO measurements per device were performed. Additionally, the success rate to achieve a valid NO value was evaluated.

RESULTS

Sixty-eight percent of the patients had FeNO values below 50 ppb. Median NO concentrations were 31 ppb (range 6-194) for BV, 33 ppb (9-164) for CN and 31ppb (7-353) for EC. Bland-Altman plots suggested an agreement within the predefined limits of ±5 ppb for all analysers within the therapeutically relevant range (0-70 ppb). The highest agreement in FeNO levels were between BV and EC with mean differences of -0.26 (95% CI -1.48 to 0.95) vs. 1.52 (95% CI 0.4-2.6) ppb for CN and EC. The results indicate an equivalence of the methods (two-one sided t test-equivalence test: p < 0.0001, ±5 ppb margins). Acceptance of the measurements was high for all devices (97%). The highest success rate to obtain 2 valid NO values without failed attempts was achieved with the BV analyser (73 vs. 62% for the CN analyser and 46% for the EC analyser).

CONCLUSIONS

For the range between 0 and 70 ppb, FeNO concentrations measured with all 3 devices were statistically equivalent within predefined acceptance criteria and did not differ in a clinically relevant way.

Comparison of three different exhaled nitric oxide analyzers in chronic respiratory disorders

BACKGROUND

Fractional exhaled nitric oxide (FeNO) measurement is a simple and non-invasive method for monitoring eosinophilic airway inflammation. New portable analyzers for FeNO measurements are constantly being developed. The aim of our study was to evaluate the agreement of FeNO values measured by new portable analyzers.

MATERIALS AND METHODS

FeNO was measured in 20 healthy subjects, 20 asthmatic and 20 chronic obstructive pulmonary disease patients using the analyzers Niox-VERO, Vivatmo-PRO and HypAir-FeNO. A linear relationship was estimated with Pearson's coefficient (r), and absolute agreement by the intraclass correlation coefficient (ICC) and bias with the limits of agreement (95% of paired differences) were assessed according to the Bland-Altman method.

RESULTS

In the study population (58 ± 14 years, 20 females), mean values of FeNO with their 95% confidence interval were 24.0 (18.6-29.4) with the Niox-VERO, 19.6 (13.6-25.7) with the Vivatmo-PRO and 20.4 (15.7-25.1) with the HypAir-FeNO. FeNO measured with the Niox-VERO was higher than the Vivatmo-PRO (mean difference of paired values +4.3; limits -16.0 to 25.7 ppb) and the HypAir-FeNO (+3.6; -12.2 to 19.4 ppb); the Vivatmo-PRO and HypAir-FeNO showed large variability of paired differences (-0.7; -16.5 to 15.0 ppb). Measurements linearly correlated with an imperfect absolute agreement: Niox-VERO versus Vivatmo-PRO r = 0.90 and ICC = 0.87; Niox-VERO versus HypAir-FeNO r = 0.93 and ICC = 0.90, Vivatmo-PRO versus HypAir-FeNO r = 0.96 and ICC = 0.93. Most of the disagreement was greater in some asthmatic patients at high values of FeNO.

CONCLUSIONS

The present study indicates that absolute exhaled NO measurements may differ to a clinically relevant extent using the Niox-VERO, Vivatmo-PRO and HypAir-FeNO analyzers. The devices cannot be used interchangeably.

Between-occasion repeatability of fractional exhaled nitric oxide measurements in children

The aim of the study was to assess short-term repeatability of measurements of fractional exhaled nitric oxide (F_ENO) and its correlates in children in the 6- to 9-year age bracket participating in a respiratory epidemiological survey. F_ENO was measured in two sessions one week apart in 101 children. Participants were divided into three groups: asymptomatic (n = 76); symptomatic (n = 14); and asthma (n = 11). Absolute and relative differences between the measurements, as well as concordance correlation coefficients, were used in order to assess repeatability. The two F_ENO measurements were strongly correlated (0.98). Although intragroup comparisons of the two measurements were not significantly different (p = 0.2), intergroup comparisons were. F_ENO measurements are reproducible in children in epidemiological settings.

Measurement of fractional exhaled nitric oxide in real-world clinical practice alters asthma treatment decisions

BACKGROUND

Assessment of asthma using clinical measures alone often fails to detect underlying airway inflammation. Fractional exhaled nitric oxide (FeNO) is a recognized biomarker of type 2 airway inflammation in asthma. Measurement of FeNO is instrumental in the assessment and management of patients with corticosteroid-sensitive asthma.

OBJECTIVE

To determine the impact of measuring FeNO on asthma management in real-world clinical practices.

METHODS

Clinicians from 337 US practices performed a clinical assessment and recorded treatment plans before and after measuring FeNO in 7,901 patients with asthma. Airway inflammation was classified as low, intermediate, or high according to the clinician's usual procedures, including clinical examination, spirometry, and symptoms. Clinicians recorded asthma medication plans, indicating medications to be initiated, continued, or stopped. FeNO measurement was performed, followed by documentation of any change(s) in the treatment plans based on the FeNO value (eg, initiating new medications or changing the dose of or discontinuing existing medications).

RESULTS

Clinical assessment was concordant with FeNO measurement in only 56% of cases, matching FeNO more frequently in patients with low inflammation (64%) vs high inflammation (34%). After FeNO measurement, clinicians modified their treatment plan in 31% and altered prescriptions for inhaled corticosteroids in 90% of cases. Inhaled corticosteroids were initiated or their dose increased in 66% of patients with high inflammation but discontinued or their dose decreased in only 9% of patients with low inflammation.

CONCLUSION

Measurement of FeNO enabled clinicians to assess underlying airway inflammation, leading to a significant revision of their treatment plans compared with real-world clinical assessment of asthma alone.

Short-term exposure to air pollution: Associations with lung function and inflammatory markers in non-smoking, healthy adults

INTRODUCTION

Air pollution impacts health by increasing mortality and the incidence of acute events in unhealthy individuals. In contrast, the acute effects of pollution in healthy individuals are less obvious. The present study was designed to evaluate the associations between short-term exposure to air pollution on one hand and lung function, and inflammatory markers on the other in middle-aged, non-smoking adults with no respiratory disease, in two urban areas in northern France.

METHODS

A sample of 1506 non-smoking adults (aged from 40 to 65) with no respiratory disease was selected from the participants in the 2011-2013 cross-sectional Enquête Littoral Souffle Air Biologie Environnement (ELISABET) survey in two urban areas in the northern France. We evaluated the associations between (i) mean levels of particulate matter with aerodynamic diameter < 10 μm (PM₁₀), nitrogen dioxide (NO₂) and ozone (O₃) exposure on the day and the day before the study examination for each participant, and (ii) spirometry data and levels of inflammatory markers. Coefficients of multiple linear regression models were expressed (except for the forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio) as the percentage change [95% confidence interval] per 10 μg increment in each pollutant.

RESULTS

Levels of PM₁₀, NO₂ and O₃ exposure were below or only close to the World Health Organization's recommended limits in our two study areas. An increment in NO₂ levels was significantly associated with a lower FEV1/FVC ratio (-0.38 [-0.64; -0.12]), a lower forced expiratory flow between 25% and 75% of FVC (FEF25-75%) (-1.70 [-3.15; -0.23]), and a lower forced expiratory flow measured at 75% of FVC (FEF75%) (-3.07 [-4.92; -1.18]). An increment in PM₁₀ levels was associated with lower FEF75% (-1.41 [-2.79; -0.01]) and a non-significant elevation in serum levels of high-sensitivity C-reactive protein (+3.48 [-0.25; 7.36], p = 0.07). Lastly, an increment in O₃ levels was associated with a significantly higher blood eosinophil count (+2.41 [0.10; 4.77]) and a non-significant elevation in fractional exhaled nitric oxide (+2.93 [-0.16; 6.13], p = 0.06).

CONCLUSION

A short-term exposure to air pollution was associated with a subclinical decrement in distal lung function and increment in inflammatory markers in healthy inhabitants of two urban areas in France. If these exploratory results are confirmed, this could suggest that even moderate levels of air pollution could have an impact on respiratory health on the general population, and not solely on susceptible individuals.

Acute ingestion of beetroot juice increases exhaled nitric oxide in healthy individuals

Background and objective

Nitric oxide (NO) plays an important role in the airways’ innate immune response, and the fraction of exhaled NO at a flow rate of 50mL per second (F_ENO₅₀) has been utilized to capture NO. Deficits in NO are linked to loss of bronchoprotective effects in airway challenges and predict symptoms of respiratory infection. While beetroot juice supplements have been proposed to enhance exercise performance by increasing dietary nitrate consumption, few studies have examined the impact of beetroot juice or nitrate supplementation on airway NO in contexts beyond an exercise challenge, which we know influences F_ENO₅₀.

Methods

We therefore examined the influence of a beetroot juice supplement on F_ENO₅₀ in healthy males and females (n = 38) during periods of rest and in normoxic conditions. F_ENO₅₀, heart rate, blood pressure, and state affect were measured at baseline, 45 minutes, and 90 minutes following ingestion of 70ml beetroot juice (6.5 mmol nitrate). Identical procedures were followed with ingestion of 70ml of water on a control day.

Results

After beetroot consumption, average values of the natural log of F_ENO₅₀ (lnF_ENO₅₀) increased by 21.3% (Cohen’s d = 1.54, p < .001) 45 minutes after consumption and by 20.3% (Cohen’s d = 1.45, p < .001) 90 min after consumption. On the other hand, only very small increases in F_ENO₅₀ were observed after consumption of the control liquid (less than 1% increase). A small subset (n = 4) of participants completed an extended protocol lasting over 3 hours, where elevated levels of F_ENO₅₀ persisted. No significant changes in cardiovascular measures were observed with this small single dose of beetroot juice.

Conclusion

As NO serves a key role in innate immunity, future research is needed to explore the potential clinical utility of beetroot and dietary nitrate to elevate F_ENO₅₀ and prevent respiratory infection.

Assessment of eosinophilic airway inflammation as a contribution to the diagnosis of occupational asthma

BACKGROUND

Ascertaining the presence of asthma through the assessment of nonspecific bronchial hyperresponsiveness (NSBH) is a key step in the diagnosis of occupational asthma (OA). We aimed at investigating whether indices of airway inflammation including fractional exhaled nitric oxide (FeNO) and sputum eosinophils would be useful adjuncts to the measurement of NSBH in diagnosing OA defined as a positive specific inhalation challenge (SIC).

METHODS

The study included 240 consecutive subjects with a suspicion of OA who completed a SIC, of whom 133 showed a positive response. The sensitivity, specificity, and predictive values of NSBH, and FeNO, as well as sputum eosinophil counts assessed at baseline of the SIC were determined.

RESULTS

A concentration of histamine inducing a 20% decline in FEV₁ (PC₂₀ ) ≤16 mg/mL showed a sensitivity of 87% and a specificity of 36%. A FeNO level ≥25 ppb and a sputum eosinophil count ≥2% provided lower sensitivity rates (47% and 39%, respectively) than the PC₂₀ value. Eight of the 17 subjects without baseline NSBH despite a positive SIC showed a sputum eosinophil count ≥2%, a FeNO level ≥25 ppb, or both outcomes. Combining either a PC₂₀ value ≤16 mg/mL or a FeNO ≥25 ppb increased the sensitivity to 91%. Using either a PC₂₀ ≤16 mg/mL or a sputum eosinophil count ≥1% increased the sensitivity to 94%.

CONCLUSION

Adding the assessment of FeNO level and sputum eosinophils to NSBH improves the identification of subjects who may have OA and require further objective testing before excluding the possibility of OA.

Clinical, functional and inflammatory characteristics in patients with paucigranulocytic stable asthma: Comparison with different sputum phenotypes

BACKGROUND

According to induced sputum cell count, four different asthma phenotypes have been recognized (eosinophilic, neutrophilic, mixed and paucigranulocytic). The aim of this study was to detect functional and inflammatory characteristics of patients with paucigranulocytic asthma.

METHODS

A total of 240 asthmatic patients were categorized into the four phenotypes according to cell counts in induced sputum. All patients underwent pulmonary function tests, and measurement of fraction of exhaled nitric oxide (FeNO). The levels of IL-8, IL-13 and eosinophilic cationic protein (ECP) were also measured in sputum supernatant. Treatment, asthma control and the presence of severe refractory asthma (SRA) were also recorded.

RESULTS

Patients were categorized into the four phenotypes as follows: eosinophilic (40%), mixed (6.7%), neutrophilic (5.4%) and paucigranulocytic (47.9%). Although asthma control test did not differ between groups (P=.288), patients with paucigranulocytic asthma had better lung function (FEV₁ % pred) [median (IQR): 71.5 (59.0-88.75) vs 69.0 (59.0-77.6) vs 68.0 (60.0-85.5) vs 80.5 (69.7-95.0), P=.009] for eosinophilic, mixed, neutrophilic and paucigranulocytic asthma, respectively, P=.009). SRA occurred more frequently in the eosinophilic and mixed phenotype (41.6% and 43.7%, respectively) and less frequently in the neutrophilic and paucigranulocytic phenotype (25% and 21.7%, respectively, P=.01). FeNO, ECP and IL-8 were all low in the paucigranulocytic, whereas as expected FeNO and ECP were higher in eosinophilic and mixed asthma, while IL-8 was higher in patients with neutrophilic and mixed asthma (P<.001 for all comparisons). Interestingly, 14.8% of patients with paucigranulocytic asthma had poor asthma control.

CONCLUSION

Paucigranulocytic asthma most likely represents a "benign" asthma phenotype, related to a good response to treatment, rather than a "true" phenotype of asthma. However, paucigranulocytic patients that remain not well controlled despite optimal treatment represent an asthmatic population that requires further study for potential novel targeted interventions.

THE PROFILE OF THE LEVEL OF ENDOGENOUS NO IN MIGRAINE SUFFERERS

Migraine is a health problem which had big impact. A neurochemistry change in the dura, that is the increase of the amount of nitrite oxide, originated from an excessive NOS (inducible NOS) activation during ictal. Some researchers assume NO as a main cause of the pain intensity in ictal. Migraine diagnosis is guided by the International Headache Society. Hopefully, this examination can be used as a more objective diagnosis in the future. Methode of this research is descriptive analytic. This study to find the level of endogenous exhaled NO on 91 subject, consisting of  30 normal people, 31 interictal, 30 ictal. An exclusion was done previously. A validation equipment and measurement had been done in accordance with American Thoracic Association guidance. The result is level of endogenous exhaled NO on the normal group (median=5), interictal group (median=11), ictal group (median=14). Coefficient correlation between VAS and level endogenous exhaled NO was 0,815. So, there is an increase of the NO endogen level in the normal people, migraine interictal, and ictal. Strong correlation between intensity of pain (VAS) and level endogenous exhaled NO during ictal.

Predictors of response to therapy with omalizumab in patients with severe allergic asthma - a real life study

OBJECTIVES

Omalizumab is a recombinant humanized IgG1 monoclonal anti-IgE antibody, used for the treatment of severe refractory allergic asthma. However, not all patients with IgE levels within the limits of administration, respond to treatment. The aim of the present study, was to determine clinical and inflammatory characteristics that could predict response to omalizumab.

METHODS

We studied retrospectively patients treated with omalizumab as per GINA guidelines in one asthma tertiary referral center. Demographic and functional characteristics, level of asthma control, fractional exhaled nitric oxide, blood and eosinophils and IgE level, induced sputum cell count, eosinophil cationic protein and Interleukin-13 in sputum supernatant were recorded. All measurements were performed before starting treatment with omalizumab. Response to treatment was evaluated according to the physician's global evaluation of treatment effectiveness. Patients were characterized as early responders when improvement was achieved within 16 weeks and as late responders when improvement was achieved between 16 and 32 weeks. Patients who did not show any improvement after 32 weeks of therapy were considered as non-responders.

RESULTS

Forty-one patients treated with omalizumab were included in the study. 28 (68.3%) patients were characterized as responders while 13 patients (31.7%) were considered as non-responders. Among responders, 25 (89%) were early responders and 3 (n = 11%) were late responders. Responders were characterized by lower baseline FEV₁ and FEV₁/FVC and higher IL-13 levels in induced sputum supernatant compared to non-responders. Late responders had higher serum IgE levels, shorter disease duration and higher number of blood eosinophils. Finally, using ROC curve analysis, the best predictors of response to omalizumab were FEV₁ (AUC = 0.718) and IL-13 in sputum supernatant (AUC = 0.709).

CONCLUSION

Lower baseline FEV₁ and higher IL-13 levels in induced sputum supernatant were predictors of response to omalizumab. Patients with higher baseline serum IgE levels, shorter disease duration and higher blood eosinophils may experience a late response and might benefit from a more prolonged treatment before being characterized as non-responders.

Fractional exhaled nitric oxide is a useful adjunctive modality for monitoring bronchial asthma

Background and Objective:

To evaluate the utility of fractional exhaled nitric oxide (FeNO) in monitoring asthma control.

Materials and Methods:

Steroid naïve nonsmoking asthmatics were recruited and followed for 6–8 weeks on standard treatment. Serial measurements of FeNO, peak expiratory flow rate (PEFR) variability, forced expiratory volume in 1 s (FEV1), bronchodilator reversibility (BDR), and asthma control test (ACT) score were measured at baseline and after 6–8 weeks of treatment.

Results:

One hundred and fifty-one patients were recruited over an 18-month period. These comprised 79 males (52.3%) with mean (standard deviation) age of 34.2 (11.6). Mean (SD) FeNO levels at baseline and after therapy were 45.4 (35.9) and 38.4 (23.7) ppb, respectively (P = 0.01). Baseline FeNO correlated strongly with FEV1 (r = −0.78, P < 0.001), ACT score (r = −0.76, P < 0.001), PEFR variability (r = −0.74, P < 0.001), and moderately with BDR (r = 0.50, P < 0.001). After treatment with inhaled steroids, the correlation remained strong with ACT score (r = −0.68, P < 0.001) but weakened with PEFR variability (r = −0.34, P = 0.01) and FEV1 (r = −0.36, P = 0.01).

Conclusions:

FeNO may be useful as an adjunctive noninvasive modality to assess asthma control in both steroid naïve asthmatics and asthmatics on treatment. However, the suboptimal sensitivity and specificity may limit its utility as a point-of-care single monitoring tool.

Both exhaled nitric oxide and blood eosinophil count were associated with mild allergic asthma only in non-smokers

BACKGROUND

The fractional exhaled nitric oxide (FENO) and the blood eosinophil count (B-eos) are markers of eosinophilic inflammation used in the diagnosis and management of asthma. The relationships between smoking cigarette and both FENO and B-eos are complex and raise questions about the association between these markers and asthma in smokers.

OBJECTIVE

To determine the relationships between both FENO and B-eos on one hand and asthma and atopy on the other, according to smoking status.

METHODS

FENO and B-eos were measured in, respectively, 1579 and 1496 of the 1607 middle-aged adults randomly selected from the general population in the cross-sectional ELISABET survey. Allergic asthma was defined as asthma (a self-report of physician-diagnosed asthma, and wheezing in the previous 12 months or the use of asthma medications) with atopy (allergic rhinitis or hayfever in the previous 12 months, or a previous positive prick test or allergen desensitization therapy). Non-allergic asthma was defined as asthma without atopy.

RESULTS

The analysis included 812 (51.4%) never, 473 (30%) former and 294 (18.6%) current smokers. A total of 490 (32%) participants were atopic, 80 (5.1%) had allergic asthma, and 31 (2%) had non-allergic asthma. Only 16.2% (18/111) of asthmatics were treated with glucocorticoid inhalants, suggesting that among them a majority of participants had mild asthma. A positive interaction between smoking status and allergic asthma was observed in multivariate models explaining FENO (P = 0.003) and B-eos (P = 0.001). Thus, compared to those without allergic asthma, participants with allergic asthma had higher FENO values (+ 63.4%, 95% CI = [39; 92]) and higher B-eos (+ 63.2% [38.2; 92.7]) in never and former smokers, but not in current smokers. Lastly, an analysis of receiver-operating characteristic curves showed that each of the two markers was able to discriminate moderately allergic asthma but only in non-smokers.

CONCLUSIONS & CLINICAL RELEVANCE

FENO and B-eos were associated with the presence of mild allergic asthma only in non-smokers, not in current smokers. These findings raise questions about the clinical value of FENO and B-eos in smokers.

Predictors of future exacerbation risk in patients with asthma

OBJECTIVES

Although modern treatment of asthma improves asthma control, some patients still experience exacerbations. The aim of the present study was to detect predictors of asthmatic exacerbations Methods: We included patients with asthma followed up in asthma clinics of 2 tertiary University hospitals. Demographic and functional characteristics, levels of exhaled NO, and inflammatory biomarkers (IL-13, ΕCP και IL-8) and cell counts in induced sputum were recorded at baseline. Measurements were performed with the patients in stability and were considered as their personal best. Patients received optimal treatment with good compliance and were followed up for 1 year for asthma exacerbations occurrence. Evaluation of the effect of recorded parameters on asthma exacerbations was performed with univariate and multivariate Poisson regression analysis.

RESULTS

171 patients (118 female) with bronchial asthma (mean age 51.6 ± 13.2 years) were included in the study. The mean number of exacerbations in 1 year of follow up was 0.4 ± 0.8 while the majority of patients (71.9%) did not experience any exacerbation. In multivariate Poisson Regression analysis only 3 characteristics were predictors of future exacerbations: FEV1 [IRR(95% CI)], [0.970(0.954-0.987)], p = 0.001, high BMI [1.078(1.030-1.129)], p = 0.001, and the need for permanent treatment with oral corticosteroids for asthma control maintenance [2.542(1.083-5.964)], p = 0.032 CONCLUSION: Optimal guideline-based asthma management results in minimal occurrence of exacerbations in the majority of patients. Predictors of exacerbations are low FEV1 levels in stability, high BMI and the need for permanent treatment with oral corticosteroids.

Evaluation of Acute Exogenous Hypoxia Impact on the Fraction of Exhaled Nitric Oxide in Healthy Males

INTRODUCTION

Exogenous hypoxia increases ventilation and contracts the pulmonary vessels. Whether those factors change the values of nitric oxide in exhaled air has not yet been evaluated.

OBJECTIVE

To examine the effect of exogenous normobaric hypoxia on the values of the fraction of nitric oxide in exhaled breath (FeNO). Subjects аnd Methods: Twenty healthy non-smoker males at mean age of 25.4 (SD = 3.7) were tested. The basal FeNO values were compared with those at 7 min. and 15 min. after introducing into the hypoxic environment (hypoxic tent), imitating atmospheric air with oxygen concentration corresponding to 3200 m above sea level. Exhaled breath temperature was measured at baseline and at 10-12 min. of the hypoxic exposition. Heart rate and oxygen saturation were registered by pulse-oximetry.

RESULTS

All the subjects had FeNO values in the reference range. The mean baseline value was 14.0 ± 3.2 ppb, and in hypoxic conditions - 15.5 ± 3.8 ppb (7 min.) and 15.3 ± 3.6 ppb (15 min.), respectively, as the elevation is statistically significant (p = 0.011 and p = 0.008). The values of exhaled breath temperature were 33.79 ± 1.55°С and 33.87 ± 1.83°С (p = 0.70) at baseline and in hypoxic conditions, respectively. Baseline oxygen saturation in all subjects was higher than that, measured in hypoxia (96.93 ± 1.29% vs. 94.27 ± 2.53%; p < 0.001).

CONCLUSIONS

Exogenous hypoxia leads to an increase of FeNO values, but does not affect the exhaled breath temperature.

Fractional exhaled nitric oxide-measuring devices: technology update

The measurement of exhaled nitric oxide (NO) has been employed in the diagnosis of specific types of airway inflammation, guiding treatment monitoring by predicting and assessing response to anti-inflammatory therapy and monitoring for compliance and detecting relapse. Various techniques are currently used to analyze exhaled NO concentrations under a range of conditions for both health and disease. These include chemiluminescence and electrochemical sensor devices. The cost effectiveness and ability to achieve adequate flexibility in sensitivity and selectivity of NO measurement for these methods are evaluated alongside the potential for use of laser-based technology. This review explores the technologies involved in the measurement of exhaled NO.

Measurement of exhaled nitric oxide concentration in asthma: a systematic review and economic evaluation of NIOX MINO, NIOX VERO and NObreath

BACKGROUND

High fractions of exhaled nitric oxide (FeNO) in the breath of patients with symptoms of asthma are correlated with high levels of eosinophils and indicate that a patient is likely to respond to inhaled corticosteroids. This may have a role in the diagnosis and management of asthma.

OBJECTIVE

To assess the diagnostic accuracy, clinical effectiveness and cost-effectiveness of the hand-held electrochemical devices NIOX MINO(®) (Aerocrine, Solna, Sweden), NIOX VERO(®) (Aerocrine) and NObreath(®) (Bedfont Scientific, Maidstone, UK) for the diagnosis and management of asthma.

DATA SOURCES

Systematic searches were carried out between March 2013 and April 2013 from database inception. Databases searched included MEDLINE, EMBASE, the Cochrane Database of Systematic Reviews, the Database of Abstracts of Reviews of Effects, Science Citation Index Expanded and Conference Proceedings Citation Index - Science. Trial registers such as ClinicalTrials.gov and the metaRegister of Controlled Trials were also searched in March 2013. All searches were updated in September 2013.

REVIEW METHODS

A rapid review was conducted to assess the equivalence of hand-held and chemiluminescent FeNO monitors. Systematic reviews of diagnostic accuracy and management efficacy were conducted. A systematic review of economic analyses was also conducted and two de novo health economic models were developed. All three reviews were undertaken according to robust high-quality methodology.

RESULTS

The rapid review (27 studies) found varying levels of agreement between monitors (Bland-Altman 95% limits of agreement up to ±10 parts per billion), with better agreement at lower FeNO values. Correlation was good (generally r > 0.9). The diagnostic accuracy review identified 22 studies in adults (all ages) and four in children. No studies used NObreath or NIOX VERO and seven used NIOX MINO. Estimates of diagnostic accuracy varied widely. FeNO used in combination with another test altered diagnostic accuracy only slightly. High levels of heterogeneity precluded meta-analysis. Limited observations included that FeNO may be more reliable and useful as a rule-in than as a rule-out test; lower cut-off values in children and in smokers may be appropriate; and FeNO may be less reliable in the elderly. The management review identified five randomised controlled trials in adults, one in pregnant asthmatics and seven in children. Despite clinical heterogeneity, exacerbation rates were lower in all studies but not generally statistically significantly so. Effects on inhaled corticosteroid (ICS) use were inconsistent, possibly because of differences in management protocols, differential effectiveness in adults and children and differences in population severity. One UK diagnostic model and one management model were identified. Aerocrine also submitted diagnostic and management models. All had significant limitations including short time horizons and the selective use of efficacy evidence. The de novo diagnostic model suggested that the expected difference in quality-adjusted life-year (QALY) gains between diagnostic options is likely to be very small. Airway hyper-responsiveness by methacholine challenge test is expected to produce the greatest QALY gain but with an expected incremental cost-effectiveness ratio (ICER) compared with FeNO (NObreath) in combination with bronchodilator reversibility of £1.125M per QALY gained. All remaining options are expected to be dominated. The de novo management model indicates that the ICER of guidelines plus FeNO monitoring using NObreath compared with guidelines alone in children is expected to be approximately £45,200 per QALY gained. Within the adult subgroup, FeNO monitoring using NObreath compared with guidelines alone is expected to have an ICER of approximately £2100 per QALY gained. The results are particularly sensitive to assumptions regarding changes in ICS use over time, the number of nurse visits for FeNO monitoring and duration of effect.

CONCLUSIONS

Limitations of the evidence base impose considerable uncertainty on all analyses. Equivalence of devices was assumed but not assured. Evidence for diagnosis is difficult to interpret in the context of inserting FeNO monitoring into a diagnostic pathway. Evidence for management is also inconclusive, but largely consistent with FeNO monitoring resulting in fewer exacerbations, with a small or zero reduction in ICS use in adults and a possible increased ICS use in children or patients with more severe asthma. It is unclear which specific management protocol is likely to be most effective. The economic analysis indicates that FeNO monitoring could have value in diagnostic and management settings. The diagnostic model indicates that FeNO monitoring plus bronchodilator reversibility dominates many other diagnostic tests. FeNO-guided management has the potential to be cost-effective, although this is largely dependent on the duration of effect. The conclusions drawn from both models require strong technical value judgements with respect to several aspects of the decision problem in which little or no empirical evidence exists. There are many potential directions for further work, including investigations into which management protocol is best and long-term follow-up in both diagnosis and management studies.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013004149.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Setting reference values for exhaled nitric oxide: a systematic review

BACKGROUND

The values obtained when the fraction of exhaled nitric oxide (FeNO) is measured are affected by several factors that are specific to the individual patient, making interpretation difficult, especially in the initial assessment of patients with respiratory symptoms.

METHODS

Systematic review of studies on FeNO reference values and individual-specific factors that influence them.

RESULTS

From 3739 references, 15 studies were included. Four studies included children and adolescents. In nine studies, samples were selected from the general population. Most studies reported objective measures for atopy (nine studies), but not for smoking status (one). Significant determinants of FeNO values reported were age and height (seven studies), atopy (six), smoking (four), weight (four), sex (three) and race (three). Additional factors were included in eight studies. R2 was reported in only five studies. The logarithmic transformation of FeNO was inadequately described in seven studies.

CONCLUSION

There are several equations for FeNO reference values that may be used in clinical practice, although the factors they include and the statistical methods they use vary considerably. We recommend the development of standard methods for the evaluation of normal FeNO data and that reference equations should be formulated based on a predetermined physiological model.

A comparison of the efficacy of once-daily fluticasone furoate/vilanterole with twice-daily fluticasone propionate/salmeterol in asthma-COPD overlap syndrome

BACKGROUND

Asthma-chronic obstructive pulmonary disease overlap syndrome (ACOS) is important because patients with ACOS have significantly worse outcomes compared with those with asthma or chronic obstructive pulmonary disease (COPD) alone. Inhaled corticosteroids (ICS), together with a long-acting β2 agonist (LABA), are recommended, but no therapeutic studies for ACOS have been conducted. Recently, fluticasone furoate/vilanterole (FF/VI) has been approved as the first once-daily ICS/LABA combination therapy for asthma and COPD.

METHODS

A 12-week, randomized, open-label cross-over study was conducted in 16 patients with ACOS to compare the effectiveness of once-daily FF/VI 200/25 μg vs. twice-daily fluticasone propionate/salmeterol (FP/SAL) 500/50 μg. The study period included a 4-week run-in, the first 4-week treatment, and the second 4-week treatment. Respiratory functions, including forced expiratory volume in 1 s (FEV1) and respiratory impedance using the forced oscillation technique (FOT), were measured, as was fractional exhaled nitric oxide (FeNO). A COPD assessment test (CAT) scores and asthma control test (ACT) scores were recorded 0, 4, and 8 weeks after randomization.

RESULTS

The mean values for the FEV1 were 1.33 (±0.29) L in the run-in period, 1.38 (±0.39) L after the FP/SAL treatment period, and 1.47 (±0.38) L after the FF/VI treatment period. The FEV1 value after the FF/VI treatment was significantly greater than the value after the run-in period (p < 0.01). FOT parameters, FeNO levels, CAT scores, ACT scores, and other blood tests were not significantly different during the run-in period, the FP/SAL treatment period, and the FF/VI treatment period.

CONCLUSIONS

FF/VI, the first once-daily ICS/LABA, can provide substantial improvement in lung functions, indicating that FF/VI should be considered for the regular treatment of ACOS.

Application of nitric oxide measurements in clinical conditions beyond asthma

Fractional exhaled nitric oxide (FeNO) is a convenient, non-invasive method for the assessment of active, mainly Th2-driven, airway inflammation, which is sensitive to treatment with standard anti-inflammatory therapy. Consequently, FeNO serves as a valued tool to aid diagnosis and monitoring in several asthma phenotypes. More recently, FeNO has been evaluated in several other respiratory, infectious, and/or immunological conditions. In this short review, we provide an overview of several clinical studies and discuss the status of potential applications of NO measurements in clinical conditions beyond asthma.

The Effect of Viral Infection on Exhaled Nitric Oxide in Children with Acute Asthma Exacerbations

BACKGROUND

Fraction of exhaled nitric oxide (Feno) level is used as an aid in the diagnosis and management of chronic asthma. Its role in acute asthma remains to be studied.

OBJECTIVE

To determine whether Feno levels are elevated in children with asthma exacerbations compared with baseline, and whether there is a difference in Feno levels based on PCR positive (+) (respiratory virus isolated by PCR analysis) versus PCR negative (-) (respiratory virus not isolated by PCR analysis) status.

METHODS

Children with a previous Feno level measurement while stable and who presented to an urgent care facility with an asthma exacerbation were enrolled. Feno levels, spirometry, and nasal swabs for viral PCR were obtained at the time of the exacerbation and following a course of prednisone. Data were available on 66 children. Linear mixed models were used to regress the outcomes of interest (FEV1, FEV1/forced vital capacity, forced expiratory flow at 25% to 75% of forced vital capacity, and natural log Feno) on detected virus (yes/no), visit (baseline, exacerbation, follow-up), and the interaction between the detected virus and visit.

RESULTS

Compared with baseline, higher Feno values and lower lung function were found at the time of an exacerbation. A respiratory virus was detected in 59% of the exacerbations. The interaction between PCR (+) and PCR (-) groups and visit on log Feno was marginally significant (P = .07). There was no difference in log Feno between the PCR (+) and PCR (-) groups at baseline, while higher log Feno was found in the PCR (-) group at the time of exacerbation and following prednisone (P = .05 and .001, respectively).

CONCLUSIONS

Higher Feno concentration in PCR (-) exacerbations suggests an eosinophilic predominance in nonviral compared with viral exacerbations.

Fractional exhaled nitric oxide: comparison between portable devices and correlation with sputum eosinophils

This study was performed to compare the 2 different portable devices measuring fractional exhaled nitric oxide (FeNO) and to see the correlation between FeNO and induced sputum eosinophil count (ISE). Forty consecutive subjects clinically suspected to have asthma underwent FeNO measurement by NIOX-MINO® and NObreath® concurrently. All also had induced sputum analysis, methacholine provocation test or bronchodilator response test, and spin prick test. Agreement between the 2 devices was evaluated. The correlation between FeNO and ISE was assessed, as well as the cut-off level of FeNO to identify ISE ≥3%. The intraclass correlation coefficient (ICC) between FeNO levels measured by NIOX-MINO® (FeNO_NIOX-MINO) and NObreath® (FeNON_Obreath) was 0.972 with 95% confidence interval of 0.948-0.985. The 95% limits of agreement were -28.9 to 19.9 ppb. The correlation coefficient between ISE and FeNO_NIOX-MINO was 0.733 (P<0.001), and 0.751 between ISE and FeNO_NObreath (P<0.001). The ROC curve found that the FeNO_NIOXMINO of 37.5 ppb and the FeNO_NObreath of 36.5 ppb identified ISE ≥3% with 90% sensitivity and 81% specificity. Age, sex, body mass index, smoking history, atopy, and the presence of asthma did not affect the FeNO level and its correlation with ISE. The NIOX-MINO ® and NObreath® agree with each other to a high degree. Both devices showed close correlation with ISE with similar cut-off value in identifying ISE ≥3%.

Respiratory symptoms, fractional exhaled nitric oxide & endotoxin exposure among female flower farm workers in Ethiopia

Background

Greenhouse workers are exposed to organic dusts, and they are thereby at risk of developing airway disorders. This study aims to measure personal endotoxin exposure, assess respiratory symptoms and measure fractional exhaled nitric oxide (FeNO) among female flower farm workers in Ethiopia.

Methods

A cross-sectional study involving female workers (n = 248) from four flower farms was conducted. The workers were interviewed for respiratory symptoms using a standard questionnaire. Workers from two of these farms also participated in personal endotoxin sampling (46 workers, 75 measurements) on glass fiber filters (0.2 μm pore size) inside conductive 25 mm Millipore cassettes for sampling of the “total dust” fraction. They also participated in FeNO (n = 114) measurements with a portable electrochemistry-based sensor. Chi-square and independent t-tests were used to compare categorical and continuous variables respectively. A mixed-effects model was used to analyze exposure determinants.

Results

Endotoxin exposure had a geometric mean (GM) of 22.8 endotoxin units (EU)/m³ with a maximum of 180 EU/m³. Greenhouse workers had significantly higher endotoxin exposure than workers outside the greenhouses (GM = 26.7 vs. 19.3 EU/m³ respectively; p < 0.05). The mean age of the workers was 24 years, and their mean working time in the flower farm was 21 months. Greenhouse workers had higher prevalence of self-reported respiratory symptoms than those outside greenhouses. However, after adjusting for education only blocked nose remained significant. The FeNO concentration ranged 5–166 ppb (GM = 14 ppb). Two workers had FeNO concentration above 50 ppb. FeNO levels differs significantly between the farms but there was no difference between workers inside and outside greenhouses.

Conclusion

Greenhouse workers at flower farms had higher prevalence of blocked nose than workers outside, which may indicate the presence of rhinitis. Endotoxin exposure was low. There were few workers with objective signs of airway inflammation; this might be because the mean working time in the greenhouses was only two years. We suggest further studies to evaluate the effect of longer employment and exposure time as well as to investigate possible exposure to pesticides and other components in the bio-aerosols.

Measurement of eNO with portable analyser might improve the management of persistent cough at primary care practice in Japan

BACKGROUND AND AIMS

There are some controversial reports that investigated the usefulness of exhaled nitric oxide (eNO) to predict the efficacy of inhaled corticosteroids (ICS) in chronic cough patients. Therefore, we retrospectively analysed the usefulness of eNO measurement with portable analyser to predict the requirement of ICS therapy in persistent cough (defined as lasting for 3 weeks or more) patients in Japan and investigated whether it might improve the management of persistent cough at primary care practice.

METHODS

We retrospectively reviewed the clinical records of adult patients who had been referred to our hospital for persistent cough from 1 June 2009 to 30 April 2011.

RESULTS

Forty-two patients had the requirement of ICS (group S) and 35 patients had no requirement of ICS (group N). Forty-three per cent of the patients who required ICS had not received ICS, and 29% of the patients who did not required ICS had received ICS. In the steroid-naive patients without current smoking, mean eNO level was significantly higher in group S [60.6 ± 14.1 parts per billion (ppb) vs 22.2 ± 2.3 ppb, P = 0.001] and the sensitivity and the specificity of eNO for predicting the requirement of ICS were 78.6% and 80.0%, respectively. The rate of the patients who received inappropriate treatment about ICS tended to be reduced from 41% to 21% if the eNO was used to predict the requirement of ICS with cut-off value of eNO 26.5 ppb (P = 0.118).

CONCLUSION

Measurement of eNO could be one of the management tools for persistent cough at primary care practice.

Contribution of exhaled nitric oxide measurement in airway inflammation assessment in asthma. A position paper from the French Speaking Respiratory Society

Nitric oxide (NO) is both a gas and a ubiquitous inter- and intracellular messenger with numerous physiological functions. As its synthesis is markedly increased during inflammatory processes, NO can be used as a surrogate marker of acute and/or chronic inflammation. It is possible to quantify fractional concentration of NO in exhaled breath (FENO) to detect airway inflammation, and thus improve the diagnosis of asthma by better characterizing asthmatic patients with eosinophilic bronchial inflammation, and eventually improve the management of targeted asthmatic patients. FENO measurement can therefore be viewed as a new, reproducible and easy to perform pulmonary function test. Measuring FENO is the only non-invasive pulmonary function test allowing (1) detecting, (2) quantifying and (3) monitoring changes in inflammatory processes during the course of various respiratory disorders, including corticosensitive asthma.

Reproducibility of exhaled nitric oxide measurements in overweight and obese adults

Background

Exhaled nitric oxide is a noninvasive measure of airway inflammation that can be detected by a handheld device. Obesity may influence the reproducibility of exhaled nitric oxide measurements, by - for instance – decreased expiratory reserve volume.

Findings

We analyzed triple exhaled nitric oxide measurements from 553 participants (aged 45 to 65 years with a body mass index ≥27 kg/m²) of the Netherlands Epidemiology of Obesity Study. The interclass correlation coefficient (single measurement reliability) was 0.965 (95% CI: 0.960, 0.970).

Conclusions

We conclude that for assessment of exhaled nitric oxide in large cohorts of overweight and obese adults a single measurement suffices.

Effect of acute dietary nitrate intake on maximal knee extensor speed and power in healthy men and women

Nitric oxide (NO) has been demonstrated to enhance the maximal shortening velocity and maximal power of rodent muscle. Dietary nitrate (NO3(-)) intake has been demonstrated to increase NO bioavailability in humans. We therefore hypothesized that acute dietary NO3(-) intake (in the form of a concentrated beetroot juice (BRJ) supplement) would improve muscle speed and power in humans. To test this hypothesis, healthy men and women (n = 12; age = 22-50 y) were studied using a randomized, double-blind, placebo-controlled crossover design. After an overnight fast, subjects ingested 140 mL of BRJ either containing or devoid of 11.2 mmol of NO3(-). After 2 h, knee extensor contractile function was assessed using a Biodex 4 isokinetic dynamometer. Breath NO levels were also measured periodically using a Niox Mino analyzer as a biomarker of whole-body NO production. No significant changes in breath NO were observed in the placebo trial, whereas breath NO rose by 61% (P < 0.001; effect size = 1.19) after dietary NO3(-) intake. This was accompanied by a 4% (P < 0.01; effect size = 0.74) increase in peak knee extensor power at the highest angular velocity tested (i.e., 6.28 rad/s). Calculated maximal knee extensor power was therefore greater (i.e., 7.90 ± 0.59 vs. 7.44 ± 0.53 W/kg; P < 0.05; effect size = 0.63) after dietary NO3(-) intake, as was the calculated maximal velocity (i.e., 14.5 ± 0.9 vs. 13.1 ± 0.8 rad/s; P < 0.05; effect size = 0.67). No differences in muscle function were observed during 50 consecutive knee extensions performed at 3.14 rad/s. We conclude that acute dietary NO3(-) intake increases whole-body NO production and muscle speed and power in healthy men and women.

Fraction of exhaled nitric oxide (FeNO ) norms in healthy Tunisian adults

Aims. To establish Fe_NO norms for healthy Tunisian adults aged 18–60 years and to prospectively assess their reliability. Methods. This was a cross-sectional analytical study. A convenience sample of healthy Tunisian adults was recruited. Subjects responded to a medical questionnaire, and then Fe_NO levels were measured by an online method (Medisoft, Sorinnes (Dinant), Belgium). Clinical, anthropometric, and plethysmographic data were collected. All analyses were performed on natural logarithm values of Fe_NO. Results. 257 adults (145 males) were retained. The proposed reference equation to predict Fe_NO value is lnFe_NO (ppb) = 3.47−0.56× height (m). After the predicted Fe_NO value for a given adult was computed, the upper limit of normal could be obtained by adding 0.60 ppb. The mean ± SD (minimum-maximum) of Fe_NO (ppb) for the total sample was 13.54 ± 4.87 (5.00–26.00). For Tunisian and Arab adults of any age and height, any Fe_NO value greater than 26.00 ppb may be considered abnormal. Finally, in an additional group of adults prospectively assessed, we found no adult with a Fe_NO higher than 26.00 ppb. Conclusion. The present Fe_NO norms enrich the global repository of Fe_NO norms that the clinician can use to choose the most appropriate norms.

Social support as a predictor exhaled nitric oxide in healthy individuals across time

Psychosocial factors such as social support and depression have long been associated with health outcomes. Elevated depressive symptoms are usually associated with worse health outcomes, whereas social support has been related to improvements in health. Nitric oxide levels are an important marker of both cardiovascular health and immune function. Research suggests that exhaled nitric oxide is affected by stress, negative affect, and depression; however, the effect of social support has not been previously explored. Thus, we sought to examine the association of social support, negative affect, and depression with exhaled nitric oxide in a group of 35 healthy individuals (10 males and 25 females) with a mean age of 20.5years across five weekly assessments. Results showed that changes in social support within individuals were positively associated with levels of exhaled nitric oxide independent of other psychosocial factors. Further exploration of the health implications of this positive relationship between airway nitric oxide and social support is necessary.