Reliability of a new hand-held device for the measurement of exhaled nitric oxide

Acute exposure to pollen and airway inflammation in adolescents

INTRODUCTION

Pollen exposure is known to exacerbate allergic asthma and allergic rhinitis symptoms, yet few studies have investigated if exposure to pollen affects lung function or airway inflammation in healthy children.

METHODS

We evaluated the extent to which higher pollen exposure was associated with differences in airway inflammation and lung function among 490 early adolescent participants (mean age of 12.9 years) in Project Viva, a prebirth cohort based in Massachusetts. We obtained regional daily total pollen counts, including tree, grass, and weed pollen, from a Rotorod pollen counter. We evaluated associations of 3- and 7-day moving averages of pollen with fractional exhaled nitric oxide (FeNO) and lung function using linear regression models and evaluated the linearity of associations with penalized splines. We tested if associations of pollen with FeNO and lung function were modified by current asthma diagnosis, history of allergic rhinitis, aeroallergen sensitivity, temperature, precipitation, and air pollution.

RESULTS

Three- and 7-day median pollen concentrations were 19.0 grains/m3 (IQR: 73.4) and 20.9 grains/m3 (IQR: 89.7). In main models, higher concentrations of total pollen over the preceding 3 and 7 days were associated with a 4.6% (95% CI: 0.1,9.2) and 7.4% (95% CI: 0.9,14.3) higher FeNO per IQR of pollen, respectively. We did not find associations of pollen with lung function in main models. Asthma, allergic rhinitis, precipitation, and air pollution (nitrogen dioxide and ozone) modified associations of pollen with lung function (Pinteraction < 0.1), while temperature, sex, and aeroallergen sensitization did not.

CONCLUSION

Short-term exposure to pollen was associated with higher FeNO in early adolescents, even in the absence of allergic sensitization and asthma.

The Impact of COVID-19 on the Oral Bacterial Flora in Patients Wearing Complete Dentures and on the Level of Exhaled Nitric Oxide as a Marker of Inflammation

BACKGROUND

Exhaled nitric oxide is helpful in the diagnosis of the inflammation process. The study aimed to analyze the impact of the COVID-19 disease on the oral bacterial flora of patients using complete dentures with a diagnostic device that measures the level of NO in exhaled air.

MATERIALS AND METHODS

The study included patients using upper and lower acrylic complete dentures. All patients participating in the study were vaccinated against COVID-19. The patients were divided into two groups. A dental examination was conducted in each group. The NO concentration was measured using the Vivatmo Pro device. An oral microbiological examination was performed by taking a swab from the bottom of the mouth.

RESULTS

There were no statistically significant differences in the distribution of NO in relation to the number of bacteria from isolated families in the study and control groups and no statistically significant correlations between the level of NO and the number of bacteria from all families in the control and study group. Significantly higher NO values were present in the vaccinated and COVID-19-positive history population compared to the vaccinated and with no COVID-19 history population (patients with no clinical symptoms of infection or unaware they had COVID-19).

CONCLUSIONS

There are statistically significant differences in NO distribution in the considered populations: vaccinated and sick, and vaccinated and with a negative history of COVID-19. The measurement of NO in exhaled air can be a complementary, non-invasive diagnostic and inflammation monitoring method.

Precipitation and Adolescent Respiratory Health in the Northeast United States

Rationale: With more frequent and intense precipitation events across the globe due to a changing climate, there is a need to understand the relationship between precipitation and respiratory health. Precipitation may trigger asthma exacerbations, but little is known about how precipitation affects lung function and airway inflammation in early adolescents. Objectives: To determine if short-term precipitation exposure is associated with lung function and airway inflammation in early adolescents and if ever having a diagnosis of asthma modifies associations of precipitation with lung function and airway inflammation. Methods: In a prospective prebirth cohort, Project Viva, that included 1,019 early adolescents born in the northeastern United States, we evaluated associations of 1-, 2-, 3-, and 7-day moving averages of precipitation in the preceding week and forced expiratory volume in 1 second, forced vital capacity, and fractional exhaled nitric oxide (FeNO) using linear regression. We used log-transformed FeNO with effect estimates presented as percentage change. We adjusted for maternal education and household income at enrollment; any smoking in the home in early adolescence; child sex, race/ethnicity, and ever asthma diagnosis; and age, height, weight, date, and season (as sine and cosine functions of visit date) at the early adolescent visit and moving averages for mean daily temperature (same time window as exposure). Results: In fully adjusted linear models, 3- and 7-day moving averages for precipitation were positively associated with FeNO but not lung function. Every 2-mm increase in the 7-day moving average for precipitation was associated with a 4.0% (95% confidence interval, 1.1, 6.9) higher FeNO. There was evidence of effect modification by asthma status: Precipitation was associated with lower forced vital capacity and higher FeNO among adolescents with asthma. We also found that outdoor aeroallergen sensitization (immunoglobulin E against common ragweed, oak, ryegrass, or silver birch) modified associations of precipitation with FeNO, with higher FeNO in sensitized adolescents compared with nonsensitized adolescents. The associations of precipitation with FeNO were not explained by relative humidity or air pollution exposure. Conclusions: We found that greater short-term precipitation may trigger airway inflammation in adolescents, particularly among those with asthma.

Multivariate Regression in Conjunction with GA-BP for Optimization of Data Processing of Trace NO Gas Flow in Active Pumping Electronic Nose

Exhaled nitric oxide trace gas at the ppb level is a biomarker of human airway inflammation. To detect this, we developed a method for the collection of active pumping electronic nose bionic chamber gas. An optimization algorithm based on multivariate regression (MR) and genetic algorithm-back propagation (GA-BP) was proposed to improve the accuracy of trace-level gas detection. An electronic nose was used to detect NO gas at the ppb level by substituting breathing gas with a sample gas. The impact of the pump suction flow capacity variation on the response of the electronic nose system was determined using an ANOVA. Further, the optimization algorithm based on MR and GA-BP was studied for flow correction. The results of this study demonstrate an increase in the detection accuracy of the system by more than twofold, from 17.40%FS before correction to 6.86%FS after correction. The findings of this research lay the technical groundwork for the practical application of electronic nose systems in the daily monitoring of FeNO.

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.

An Evidence-Based Review of Application Devices for Nitric Oxide Concentration Determination from Exhaled Air in the Diagnosis of Inflammation and Treatment Monitoring

The measurement of nitric oxide (NO) in exhaled air is used in diagnostics and monitoring the pathologies not only in the respiratory system but also in the oral cavity. It has shown a huge increase in its level in asthma and diseases of the oral cavity. It seems reasonable to undertake research on the impact of inflammation on the level of NO in exhaled air. The aim of the study is to make an evidence-based review of the application of NO levels in exhaled air in the diagnosis of inflammation and treatment monitoring on the basis of selected measuring devices. Methods and Results: This paper presents an example of the application of NO measurement in exhaled air in individual human systems. Selected measuring devices, their non-invasiveness, and their advantages are described. Discussion: The usefulness of this diagnostic method in pathologies of the oral cavity was noted. Conclusions: Measuring the level of NO in exhaled air seems to be a useful diagnostic method.

Pilot Study of Use of Nitric Oxide in Monitoring Multiple Dental Foci in Oral Cavity—A Case Report

Background: The most common cause of implant loss and deteriorating restoration aesthetics is infection and chronic inflammation of the tissues around the implants. Inflammation in the oral cavity, confirmed by clinical and histopathological examination and determination of exhaled nitric oxide, is a situation which may cause the complications on the whole human body. Elimination of the patology in the oral cavity in some cases is the only resonable treatment. The aims and objectives of our work is to present a gradual treatment of advanced infalmmation and present huge reduction stamp of inflammation measured with marker nitric oxide (NO) in exhaled air. Materials and Methods: Simple treatment containing elimantion of pathology in the oral cavity was conducted. Patient that came to the dental practice suffered from the inflammation caused by lack of proper hygiene. First aid in this situation was to eliminate the inflammation which may affect negatively for general health. At first visit full hygienization was performed, at the second visit roots of abutment teeth and implants were removed under local anesthesia along with cystic changes. Results: The hygiene precedures and extraction of the unsteady inflammationprosthetic restorations significantly decreased the level of NO in exhaled air. Conclusions: During the examination of the patient coming to the dental practice great attention should be paid to the coexistence of pathologies related to the oral cavity. Omission of a dental examination and possible elimination of odontogenic foci may affect the implication of the results of general diagnostics and subsequent treatment. Measuring the level of NO on exhaled air seems to be useful diagnostic method.

Importance of type and degree of IgE sensitisation for defining fractional exhaled nitric oxide reference values

BACKGROUND

Fractional exhaled nitric oxide (FE_NO) is a marker of type 2 airway inflammation used in clinical practice in asthma. However, reference values are needed to broaden the clinical use of FE_NO and this is within the scope of a newly started Global Lung Function Initiative task force. We aim to study FE_NO levels with special emphasis on the upper limit of normal (ULN) in relation to the type and degree of IgE sensitisation.

METHODS

FE_NO was measured in 1855 non-smoking, respiratory healthy subjects from the Swedish CArdioPulmonary bioImage Study (SCAPIS). Atopic subjects (n = 424), defined as being IgE-sensitised to aeroallergens (ImmunoCAP Phadiatop™, ≥0.35 PAU/l) were compared to non-atopic subjects (<0.35 PAU/l, n = 1431). Atopic subjects were further characterised according to their grade of IgE sensitisation (IgE antibody tertiles: (T1<1.16, T2 1.16-3.72 and T3 >3.72 PAU/l) and sensitisation to perennial (cat or mite) or seasonal (birch) allergens.

RESULTS

Subjects IgE-sensitised to cat or mite had higher FE_NO compared to non-atopic subjects (FE_NO (ppb): median 20.0 vs. 15.0, and ULN 50.4 vs. 33.0, p < 0.001). This was seen to a lesser extent for subjects IgE-sensitised to birch only (median 18.0 vs. 15.0, and ULN 38.0 vs. 33.0, p = 0.048). Atopic subjects with a high degree of IgE sensitisation (Phadiatop: >3.72 PAU/l) had the highest FE_NO compared to non-atopic subjects (median 20.0 vs. 15.0, and ULN 56.0 vs. 33.0, p < 0.001).

CONCLUSIONS

The type and degree of IgE sensitisation should be considered in generating FE_NO reference values.

Determining the Best Tool Comparable with Global Initiative for Asthma Criteria for Assessing Pediatric Asthma Control

Background: Guidelines such as Global Initiative for Asthma (GINA) recommend disease control as the mainstay of asthma management. Objective: To investigate which measure of asthma control best correlates with the GINA criteria for determining asthma control in children. Methods: Child asthma-patients at a tertiary hospital were enrolled in the study after evaluation of response to treatment. Asthma control test (ACT)/pediatric asthma control test (PACT), Pediatric Asthma Quality of Life Questionnaire (PAQLQ), fractional exhaled nitric oxide (FeNO), and lung function parameters were evaluated. Patients were examined by asthma specialists and control status was evaluated based on GINA. Results: The median age (interquartile range) of patients was 10.7 (8.4-12.9) years, 57.9% of patients were boys. Of 228 children, 84.2%, 9.6%, and 6.1% displayed "well-controlled", "partially controlled", and "uncontrolled" asthma, respectively, according to GINA. The patients with "partially controlled" and "uncontrolled" asthma were grouped as "not well-controlled." The cutoff levels were 22, 21, and 5.9 for PACT, ACT, and PAQLQ, respectively, for determining "well-controlled" asthma (P < 0.001). With these cutoff values, ACT exhibited higher comparability with GINA than PACT and PAQLQ (κ = 0.473, 0.221, and 0.150, respectively, P < 0.001). PAQLQ had higher agreement with GINA criteria in children ≥12 years old (κ = 0.326, P < 0.001 and κ = 0.151, P = 0.014, respectively). Correctly classified patients with PACT, ACT, and PALQLQ based on GINA with these cutoff levels were 93 (64.1%), 63 (75.9%), and 139 (62.9%), respectively. FeNO and lung function parameters were unsuccessful at revealing control status according to GINA. Conclusion: ACT is better than PACT for comparability with GINA. Better correlation of PAQLQ and ACT and better comparability of PAQLQ and GINA were evident in older children.

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

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.

Obesity, sedentary lifestyle, and exhaled nitric oxide in an early adolescent cohort

Fractional exhaled nitric oxide (FeNO) is a marker of airway inflammation that is well-characterized in allergic disease states. However, FeNO is also involved in nonallergic inflammatory and pulmonary vascular mechanisms or responses to environmental stimuli. We sought to determine the extent to which obesity or sedentary lifestyle is associated with FeNO in adolescents not selected on the basis of allergic disease. In Project Viva, a prebirth cohort study, we measured body mass index (BMI), skinfold thicknesses, waist circumference, body fat, hours watching television, hours of physical activity, and heart rate after exercise among 929 adolescents (median age, 12.9). We measured FeNO twice and averaged these as a continuous, log-transformed outcome. We performed linear regression models, adjusted for child age, sex, height, and race/ethnicity, maternal education and smoking during pregnancy, household income and smoking, and neighbourhood characteristics. In secondary analysis, we additionally adjusted for asthma. More than 2 hours spent watching TV was associated with 10% lower FeNO (95% confidence interval [CI]: -20, 0%). Higher body fat percentage was also associated with lower FeNO. After additional adjustment for asthma, teens who are underweight (BMI <5th %tile, 3%) had 22% lower FeNO (95%CI: -40, 2%) and teens who are overweight (BMI ≥85th %ile, 28%) had 13% lower FeNO (95%CI: -23, -2%). Each of these associations of lifestyle and body weight with lower FeNO were greater in magnitude after adjusting for asthma. In summary, sedentary lifestyle, high and low BMI were all associated with lower FeNO in this adolescent cohort.

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.

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.

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.

Association of short-term exposure to ambient air pollutants with exhaled nitric oxide in hospitalized patients with respiratory-system diseases

BACKGROUND

Previous studies have suggested that exposure to ambient air pollutants may adversely affect human health. However, few studies have examined the health effects of exposure to ambient air pollutants in hospitalized patients.

OBJECTIVES

To evaluate the association between short-term exposure to ambient air pollutants and exhaled nitric oxide fraction (FeNO) in a large cohort of hospitalized patients.

METHODS

FeNO was detected for 2986 hospitalized patients (ages 18-88 years). Daily average concentrations of SO₂, NO₂, O₃, CO, PM_2.5 and PM₁₀ in 2014 and 2015 were obtained from nine fixed-site monitoring stations. Multiple linear regression models were chosen to assess the associations of exposure to ambient air pollutants with FeNO while adjusting for confounding variables. Lagged variable models were selected to determine the association between FeNO and ambient air pollutants concentrations with lags of up to 7 days prior to FeNO testing.

RESULTS

Interquartile-range (IQR) increases in the daily average SO₂ (8.00 μg/m³) and PM_2.5 (37.0 μg/m³) were strongly associated with increases in FeNO, with increases of 3.41% [95% confidence interval (CI), 0.94-5.93%] and 2.72% (95%CI, -0.09% to 5.61%), respectively. However, FeNO levels were not statistically associated with PM₁₀, NO₂, O₃ or CO. In the two-pollutant models, the maximum correlation was for ambient SO₂. We also found that FeNO was associated with IQR increases in daily average ambient concentrations of SO₂ up to 3 and 4 days after the exposure events.

CONCLUSIONS

Short-term exposure to SO₂ and PM_2.5 were positively correlated with FeNO levels in hospitalized patients in Shanghai.

A Randomized Pragmatic Trial of Changing to and Stepping Down Fluticasone/Formoterol in Asthma

BACKGROUND

Guidelines recommend reducing treatment in patients with well-controlled asthma after 3 months of stability. However, there is inadequate real-life data to guide physicians on therapy change in daily practice.

OBJECTIVE

To assess asthma control after change to and step-down of fluticasone propionate/formoterol fumarate dihydrate (FP/FOR) in real-life patients.

METHODS

In a randomized controlled, pragmatic, open-label trial, 225 well-controlled patients with asthma were randomized (1:2) to maintain high-dose fluticasone propionate/salmeterol xinafoate (FP/SAL, 1000/100 μg) or switch to FP/FOR (1000/40 μg) daily for 12 weeks (phase 1). One hundred sixteen patients stable on FP/FOR at week 12 were subsequently randomized (1:1) to maintain this therapy, or stepped down to FP/FOR (500/20 μg) daily for 12 weeks (phase 2). The primary end point was the 7-question Asthma Control Questionnaire (ACQ7) score.

RESULTS

In phase 1, FP/FOR (1000/40 μg) (n = 126) was noninferior to FP/SAL (1000/100 μg) (n = 73) for ACQ7 (difference in means, -0.12; 95% CI, -0.32 to 0.09). In phase 2, FP/FOR (500/20 μg) (n = 52) was noninferior to FP/FOR (1000/40 μg) (n = 52) for ACQ7 (difference in means, 0.01; 95% CI, -0.20 to 0.22). There was no significant difference in exacerbation rate between the groups in either phase. However, 1 to 2 exacerbations in 12 months before phase 1 were associated with the occurrence of an exacerbation after step-down (P = .007).

CONCLUSIONS

In patients with well-controlled asthma, a change from FP/SAL to FP/FOR did not compromise asthma control. Step-down of FP/FOR was well tolerated; however, in contrast to current guidelines, our data suggest caution in stepping down patients uncontrolled in the last 12 months. Larger step-down studies are required to confirm these findings.

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.

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.

Exhaled nitric oxide in school children: Searching for the lost variability

OBJECTIVE

The factors - including asthma and rhinoconjunctivitis - which influence FeNO values in a general population of school children have been studied in order to know to what extent the variability of those values can be explained.

METHODS

FeNO was measured in a population of 240 school children aged 6-12 years by means of a Niox-Mino™ device in a standardised way. Parents filled in an ISAAC-validated questionnaire of symptoms and environmental factors. Diagnoses were checked against clinical records. Height and weight were measured. A multivariate regression analysis including all variables in the questionnaire was performed, which was followed by two Xi stepwise tests in order to build a predictive model which included the main variables influencing FeNO values.

RESULTS

Among the 240 children, 10 suffered from asthma, 16 from rhinoconjunctivitis and 15 from both conditions. FeNO values (GM±GSD) in children with rhinoconjunctivitis (19.61±1.20ppb), with asthma (18.62±1.32ppb), and with both conditions (17.62±1.19ppb) tended to be significantly higher than control children (11.42±1.04ppb), p=0.0016, p=0.08 and p=0.01, respectively. The different predictive models were able to explain only 20-27% of FeNO variability.

CONCLUSIONS

The proportion of FeNO inter-individual variability which can be explained by individual (including suffering from asthma or rhinoconjunctivitis), family, and environmental factors is very low (20-27%). This could have implications on the usefulness of FeNO as a diagnostic tool in asthma.

Exercise-Induced Changes in Exhaled NO Differentiates Asthma With or Without Fixed Airway Obstruction From COPD With Dynamic Hyperinflation

Asthmatic patients with fixed airway obstruction (FAO) and patients with chronic obstructive pulmonary disease (COPD) share similarities in terms of irreversible pulmonary function impairment. Exhaled nitric oxide (eNO) has been documented as a marker of airway inflammation in asthma, but not in COPD. To examine whether the basal eNO level and the change after exercise may differentiate asthmatics with FAO from COPD, 27 normal subjects, 60 stable asthmatics, and 62 stable COPD patients were studied. Asthmatics with FAO (n = 29) were defined as showing a postbronchodilator FEV1/forced vital capacity (FVC) ≤70% and FEV1 less than 80% predicted after inhaled salbutamol (400 μg). COPD with dynamic hyperinflation (n = 31) was defined as a decrease in inspiratory capacity (ΔIC%) after a 6 minute walk test (6MWT). Basal levels of eNO were significantly higher in asthmatics and COPD patients compared to normal subjects. The changes in eNO after 6MWT were negatively correlated with the percent change in IC (r = -0.380, n = 29, P = 0.042) in asthmatics with FAO. Their levels of basal eNO correlated with the maximum mid-expiratory flow (MMEF % predicted) before and after 6MWT. In COPD patients with air-trapping, the percent change of eNO was positively correlated to ΔIC% (rs = 0.404, n = 31, P = 0.024). We conclude that asthma with FAO may represent residual inflammation in the airways, while dynamic hyperinflation in COPD may retain NO in the distal airspace. eNO changes after 6MWT may differentiate the subgroups of asthma or COPD patients and will help toward delivery of individualized therapy for airflow obstruction.

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.

Airway inflammation and ammonia exposure among female Palestinian hairdressers: a cross-sectional study

OBJECTIVES

Little is known about the working conditions and airway inflammation in hairdressers in Palestine. We aimed to investigate if hairdressers in Palestine have a higher level of airway inflammation as compared to a control group. We also assessed the hairdressers' physical working conditions and exposure to ammonia gases at the hair salons. Lastly, we investigated the association between ammonia levels and inflammation markers in the airways and the blood.

METHODS

Our study participants were 33 non-smoking hairdressers (aged 19-50 years) and 35 non-smoking control subjects (aged 18-49 years). Both groups answered a questionnaire on respiratory symptoms, and performed lung function and exhaled nitric oxide (eNO) tests. Blood and sputum samples were collected from all participants and air concentration levels of ammonia were measured in 13 salons.

RESULTS

Hairdressers had a higher level of sputum neutrophil count (absolute numbers/mg sputum (median (25th-75th centiles)) compared to controls, 376 (183-980) and 182 (96-358), respectively. Hairdressers also had significantly elevated eNO and blood C reactive protein (CRP) levels compared to the control subjects, controlled for age and body mass index. Exposure measurements showed that the hairdressers in salons with scarce ventilation were exposed to ammonia concentration, ranging from 3 to 61 mg/m(3).

CONCLUSIONS

Compared to unexposed controls, the hairdressers had signs of neutrophilic airway inflammation, higher eNO levels and higher CRP. The hairdressers were exposed to high concentrations of ammonia from hairdressing chemicals and their working conditions were unsatisfactory.

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.

Clinical and biological markers of asthma control

Asthma has substantial impact on the patient, their family and health systems, and its control has gained increasing attention. Perception of asthma control has varied widely among patients as well as healthcare providers. Several clinical markers have been developed to define and standardize the measurement of asthma control. They are based primarily on patients' symptoms and have been popular in clinical practice and in clinical studies. With the advances in basic research on the pathology of asthma, several biological markers have evolved that have the advantages of being objective, quantitative and more reflective of the underlying pathology, which makes them a better guide for selecting optimal therapy. In addition to the cost and expertise required, biological makers are influenced by multiple factors that limit their application in clinical practice. Ongoing research is expected to define the role of individual biological markers, the optimal method of their application, and their appropriate interpretation.

Effect of shisha (waterpipe) smoking on lung functions and fractional exhaled nitric oxide (FeNO) among Saudi young adult shisha smokers

Shisha (waterpipe) smoking is becoming a more prevalent form of tobacco consumption, and is growing worldwide, particularly among the young generation in the Middle East. This cross-sectional study aimed to determine the effects of shisha smoking on lung functions and Fractional Exhaled Nitric Oxide (FeNO) among Saudi young adults. We recruited 146 apparently healthy male subjects (73 control and 73 shisha smokers). The exposed group consisted of male shisha smokers, with mean age 21.54 ± 0.41 (mean ± SEM) range 17-33 years. The control group consisted of similar number (73) of non-smokers with mean age 21.36 ± 0.19 (mean ± SEM) range 18-28 years. Between the groups we considered the factors like age, height, weight, gender, ethnicity and socioeconomic status to estimate the impact of shisha smoking on lung function and fractional exhaled nitric oxide. Lung function test was performed by using an Spirovit-SP-1 Electronic Spirometer. Fractional Exhaled Nitric Oxide (FeNO) was measured by using Niox Mino. A significant decrease in lung function parameters FEV1, FEV1/FVC Ratio, FEF-25%, FEF-50%, FEF-75% and FEF-75-85% was found among shisha smokers relative to their control group. There was also a significant reduction in the Fractional Exhaled Nitric Oxide among Shisha smokers compared to control group.

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.

Exhaled nitric oxide in childhood allergic asthma management: a randomised controlled trial

OBJECTIVE

We investigated the potential yield of incorporating fractional exhaled nitric oxide (FeNO) measurements in childhood allergic asthma management.

METHODS

Ninety-nine children with persistent allergic asthma were included in this multicentre, single-blind, randomized controlled trial. Treatment was based on the Global Initiative for Asthma (GINA) guidelines. In the FeNO group, asthma management was also guided by FeNO measurements. Health outcomes were evaluated over a 52-week timeframe.

RESULTS

Fewer asthma exacerbations were registered in the FeNO group. 24% of the children in the FeNO group experienced one or more exacerbations per year, compared with 48% in the clinical group (P = 0.017). The proportion of symptom-free days did not differ between groups. In the FeNO group, more months of leukotriene receptor antagonist use (median (interquartile range)) were observed: 12 (9-12) months, compared with 9 (3-12) months in the clinical group (P = 0.019). Next, the evolution of inhaled corticosteroid doses between visits 1 and 5 (median change (interquartile range)) showed a significant increase of +100 µg (0, +400) in the FeNO group and a change of 0 µg (-200, +80) in the clinical group (P = 0.016).

CONCLUSIONS

FeNO measurements in childhood asthma management did not improve the proportion of symptom-free days, but did result in fewer asthma exacerbations associated with an increased leukotriene receptor antagonist use and an augmentation of the inhaled corticosteroid doses.

Office-based exhaled nitric oxide measurement in children 4 years of age and older

BACKGROUND

Fractional exhaled nitric oxide (FENO) is increasingly being used in the office-based management of asthma, but data in children are limited.

OBJECTIVES

To report FENO values in 4- to 7-year-old children with suspected asthma and characterize their relation to clinical variables and describe the relation among FENO levels, age, and sex in 4- to 18-year-old children with suspected asthma.

METHODS

Retrospective data in 4- to 18-year-old children (n = 825) who underwent FENO testing using the NIOX MINO device were collected and analyzed. Chart reviews were performed for the 4- to 7-year-old children (n = 75).

RESULTS

FENO values ranged from less than or equal to 5 to 89 ppb in 75 4- to 7-year-old children and less than or equal to 5 to 300 ppb in 750 > 7 to 18-year-old children. Approximately one tenth of 4- to 7-year-old children and one third of > 7 to 18-year-old children had FENO values indicative of eosinophilic/allergic inflammation (>35 ppb). In regression analysis of the 4- to 7-year-old children, increasing age (P = .03) and asthma severity (P = .01) were associated with higher FENO levels. Atopic dermatitis was significantly associated (P = .03), whereas allergic rhinitis was marginally associated (P = .06), with higher FENO levels. Inhaled corticosteroid use was associated with lower FENO levels (P = .02).

CONCLUSION

This study characterizes the largest cohort of 4- to 7-year-old children to undergo FENO testing in ambulatory asthma management. Correlations between FENO levels and clinical variables were consistent with established findings in older children. This preliminary real-world study suggests that FENO assessment may be feasible and useful in the office-based asthma management of children as young as 4 years.

DASH for asthma: a pilot study of the DASH diet in not-well-controlled adult asthma

This pilot study aims to provide effect size confidence intervals, clinical trial and intervention feasibility data, and procedural materials for a full-scale randomized controlled trial that will determine the efficacy of Dietary Approaches to Stop Hypertension (DASH) as adjunct therapy to standard care for adults with uncontrolled asthma. The DASH diet encompasses foods (e.g., fresh fruit, vegetables, and nuts) and antioxidant nutrients (e.g., vitamins A, C, E, and zinc) with potential benefits for persons with asthma, but it is unknown whether the whole diet is beneficial. Participants (n = 90) will be randomized to receive usual care alone or combined with a DASH intervention consisting of 8 group and 3 individual sessions during the first 3 months, followed by at least monthly phone consultations for another 3 months. Follow-up assessments will occur at 3 and 6 months. The primary outcome measure is the 7-item Juniper Asthma Control Questionnaire, a validated composite measure of daytime and nocturnal symptoms, activity limitations, rescue medication use, and percentage predicted forced expiratory volume in 1 second. We will explore changes in inflammatory markers important to asthma pathophysiology (e.g., fractional exhaled nitric oxide) and their potential to mediate the intervention effect on disease control. We will also conduct pre-specified subgroup analyses by genotype (e.g., polymorphisms on the glutathione S transferase gene) and phenotype (e.g., atopy, obesity). By evaluating a dietary pattern approach to improving asthma control, this study could advance the evidence base for refining clinical guidelines and public health recommendations regarding the role of dietary modifications in asthma management.

Enhanced generation of suppressor T cells in patients with asthma taking oral contraceptives

Introduction. A dysregulation of regulatory T cells (Tregs) could play a major role in the pathogenesis of bronchial asthma. Sex-dependent differences as well as the impact of hormonal changes in the incidence and severity of asthma are widely recognized. Emerging evidence suggests that asthma symptoms are alleviated in female patients taking hormone oral contraceptives (OCs). The impact of OCs on the generation of induced Tregs (iTregs) was assessed in a cohort of female patients with asthma. Methods. Thirteen patients were included in this pilot study. During three distinct phases of their menstrual cycles, we measured exhaled nitric oxide (eNO) levels, forced expiratory volume at 1 second (FEV1s), asthma control test (ACT) score, sex steroid hormone levels in serum, natural Tregs in peripheral blood, and the ability of CD4(+) T cells to generate iTregs ex vivo. Results. The luteal serum levels of estradiol and progesterone negatively correlated with the proportion of iTregs generated ex vivo in patients not taking OCs. In addition, physiological doses of estradiol and progesterone prevented the acquisition of a suppressor T cell phenotype in vitro. Interestingly, patients taking OCs had reduced serum sex hormone levels associated with higher iTreg induction, a better ACT score, and a tendency toward lower eNO levels. Conclusions. Our results identify an impact of sex hormones on the capacity of T cells to polarize towards a regulatory phenotype and suggest the regulation of peripheral T cell lineage plasticity as a potential mechanism underlying the beneficial effects of OCs in women with asthma.

Comparison of two exhaled nitric oxide analyzers: the NIOX MINO hand-held electrochemical analyzer and the NOA280i stationary chemiluminescence analyzer

BACKGROUND AND OBJECTIVE

Measurement of the fraction of nitric oxide (FeNO) in exhaled air is useful in the management of asthma. A new hand-held nitric oxide (NO) analyzer, the NIOX MINO, is simple and easy to use in clinical practice. In this study, FeNO values measured using the NIOX MINO were compared with those obtained using a stationary chemiluminescence analyzer, the Sievers NOA280i.

METHODS

FeNO was measured in 100 adults, using both the NIOX MINO and the NOA280i. Nine (9.0%) of these subjects had asthma. The first acceptable measurement with the NIOX MINO and the mean of two acceptable measurements with the NOA280i were compared.

RESULTS

There was a significant correlation between FeNO concentrations measured with the two devices (r = 0.876, P < 0.001). A Bland-Altman plot showed a high degree of agreement between the two devices: the mean inter-device difference was 3.3 parts per billion (ppb), and the 95% limits of agreement were -7.0 and 13.6 ppb. In addition, the mean relative difference was 14.5%, with the 95% limits of agreement being -33.7 and 62.7%. The mean value (± standard error of the mean) for FeNO as measured with the NIOX MINO (18.8 ± 0.9 ppb) was significantly lower than that measured with the NOA280i (22.1 ± 1.2 ppb, P < 0.001).

CONCLUSIONS

There was a significant correlation, but only moderate agreement, between FeNO values measured with the NIOX MINO and those measured with the NOA280i, with the NIOX MINO values being significantly lower than the NOA280i values. Significant differences in FeNO values obtained with these two NO analyzers should be considered when interpreting the results of FeNO measurements.

Fractional exhaled nitric oxide among cement factory workers: a cross sectional study

BACKGROUND

It has been suggested that dust exposure causes airway inflammation among cement factory workers. However, there is limited information on the mechanisms of this effect. We explored any associations between total dust exposure and fractional exhaled nitric oxide (FENO) as a marker of airway eosinophilic inflammation among cement production workers in Tanzania. We also examined possible differences in FENO concentration between workers in different parts of the production line.

METHODOLOGY

We examined 127 cement workers and 28 controls from a mineral water factory. An electrochemistry-based NIOX MINO device was used to examine FENO concentration. Personal total dust was collected from the breathing zone of the study participants using 37 mm cellulose acetate filters placed in three-piece plastic cassettes. Interviews on workers' background information were conducted in the Swahili language.

RESULTS

We found equal concentrations of FENO among exposed workers and controls (geometric mean (GM)=16 ppb). The GM for total dust among the exposed workers and controls was 5.0 and 0.6 mg/m(3), respectively. The FENO concentrations did not differ between the exposed workers with high (GM≥5 mg/m(3)) and low (GM<5 mg/m(3)) total dust exposure. There was no significant difference in FENO concentration between workers in the two main stages of the cement production process.

CONCLUSIONS

We did not find any difference in FENO concentration between dust-exposed cement workers and controls, and there were similar FENO concentrations among workers in the two main stages of cement production.

Fractional exhaled nitric oxide in Chinese children with asthma and allergies--a two-city study

Fractional exhaled nitric oxide (FeNO) is a non-invasive biomarker of eosinophilic airway inflammation. Our aim was to study associations between FeNO in Chinese children in two cities and asthma, asthmatic symptoms, rhinitis, eczema, and selected childhood and home environmental factors. A random sample of children in Shanghai (n = 187) and Taiyuan (n = 127), and additional randomly selected children reporting current wheeze (n = 115) were invited for FeNO measurements by NIOX MINO. A questionnaire survey was performed among all subjects (12-14 y) in 59 classes in Shanghai and 44 in Taiyuan. Associations were studied using multiple linear regression using 10log transformed FeNO data and mutual adjustment. The geometric mean FeNO in the random sample (GM ± GSD) was higher in Shanghai (16.2 ± 1.9 ppb) as compared to Taiyuan (12.8 ± 1.6 ppb) (P < 0.001). In the total material (n = 429), Shanghai residency (P = 0.001), male gender (P = 0.02), parental asthma/allergy (P = 0.04), doctors' diagnosed asthma (DDA) (P < 0.001) and current wheeze (P < 0.001) were associated with higher FeNO levels. In non-wheezers (n = 291), Shanghai residency (P = 0.007), male gender (P = 0.002), DDA (P = 0.04), current rhinitis (P = 0.004) and reported pollen/furry pet allergy (P = 0.04) were positively associated with FeNO. In wheezers (n = 138), DDA was the only significant factor (P = 0.009). In conclusion, male gender, current wheeze, DDA, parental asthma/allergy, current rhinitis, pollen/furry pet allergy can be independent determinants of increased FeNO. The lower level of FeNO in Taiyuan is in agreement with previous studies showing lower prevalence of asthma and allergy in Taiyuan as compared to Shanghai.

Comparative repeatability of two handheld fractional exhaled nitric oxide monitors

BACKGROUND

The use of portable fractional exhaled nitric oxide (FENO) devices is increasingly common in the diagnosis and management of allergic airways inflammation.

METHODS

We tested two handheld FENO devices, to determine (a) if there was adequate intradevice repeatability to allow the use of single breath testing, and (b) if the devices could be used interchangeably. In a mixed pediatric population, including normal, asthmatic, and children with peanut allergies, 858 paired values were collected from the NIOX-MINO® and/or the NObreath® devices.

RESULTS

The NIOX-MINO® showed excellent repeatability (mean difference of 0.1 with 95% limits of agreement between -7.93 to 7.72 ppb), while the NObreath® showed good repeatability (mean difference of -1.61 with 95% limits of agreement between -14.1 and 10.8 ppb). Intradevice repeatability was good but not adequate and the NIOX-MINO® systematically produced higher results than the NObreath® [mean difference of 7.8 ppb with 95% limits of agreement from -11.55 to 27.52 ppb (-33% to 290%)].

CONCLUSIONS

Our results support the manufacturer's advice that single breath testing is appropriate for the NIOX-MINO®. NObreath® results indicate that the mean of more than one breath should be utilized. The devices cannot be used interchangeably.

Identifying uncontrolled asthma in children with the childhood asthma control test or exhaled nitric oxide measurement

BACKGROUND

International guidelines highlight the importance of assessing asthma control status in children with asthma, and research on practical and objective instruments for assessing asthma control is ongoing.

OBJECTIVE

To determine the role of the Childhood Asthma Control Test (C-ACT) and fractional concentration of exhaled nitric oxide (FeNO) in identifying children with not well-controlled asthma.

METHODS

Children 6 to 11 years of age with asthma were enrolled in the study. They completed C-ACT and underwent FeNO and spirometric measurements during the monthly clinic visits. An asthma specialist assessed asthma control according to the gold standard Global Initiative for Asthma guideline and decided the treatment of the patients.

RESULTS

Seventy-six children with a mean (SD) age of 8.7 (1.4) years were evaluated in the first visit, whereas 64 and 51 children were admitted for second and third visits, respectively. A C-ACT score of 22 or less had 69% sensitivity and 77% specificity in determining not well-controlled asthma, whereas an FeNO value of 19 ppb or higher had 61% sensitivity and 59% specificity in patients who completed 3 visits. Receiver operating characteristic curve analysis revealed that the C-ACT was better than FeNO for identifying patients with not well-controlled asthma (area under the curve, 0.79; P < .001 [C-ACT] vs .58, P = .10 [FeNO]) Results of multivariate generalized estimating equation analysis revealed that a C-ACT score of 22 or less (odds ratio, 8.75; 95% confidence interval, 4.35-17.59; P < .001) and an FeNO of 19 ppb or greater (odds ratio, 2.60; 95% confidence interval, 1.07-6.29; P = .03) were significant indicators for the presence of not well-controlled asthma.

CONCLUSION

The C-ACT is superior to FeNO in determining the control status of children with asthma and may be used as a complementary tool in clinical practice to detect children with not well-controlled asthma.

Air pollution and acute respiratory response in a panel of asthmatic children along the U.S.-Mexico border

BACKGROUND

Concerns regarding the health impact of urban air pollution on asthmatic children are pronounced along the U.S.-Mexico border because of rapid population growth near busy border highways and roads.

OBJECTIVES

We conducted the first binational study of the impacts of air pollution on asthmatic children in Ciudad Juarez, Mexico, and El Paso, Texas, USA, and compared different exposure metrics to assess acute respiratory response.

METHODS

We recruited 58 asthmatic children from two schools in Ciudad Juarez and two schools in El Paso. A marker of airway inflammation [exhaled nitric oxide (eNO)], respiratory symptom surveys, and pollutant measurements (indoor and outdoor 48-hr size-fractionated particulate matter, 48-hr black carbon, and 96-hr nitrogen dioxide) were collected at each school for 16 weeks. We examined associations between the pollutants and respiratory response using generalized linear mixed models.

RESULTS

We observed small but consistent associations between eNO and numerous pollutant metrics, with estimated increases in eNO ranging from 1% to 3% per interquartile range increase in pollutant concentrations. Effect estimates from models using school-based concentrations were generally stronger than corresponding estimates based on concentrations from ambient air monitors. Both traffic-related and non-traffic-related particles were typically more robust predictors of eNO than was nitrogen dioxide, for which associations were highly sensitive to model specification. Associations differed significantly across the four school-based cohorts, consistent with heterogeneity in pollutant concentrations and cohort characteristics. Models examining respiratory symptoms were consistent with the null.

CONCLUSIONS

The results indicate adverse effects of air pollution on the subclinical respiratory health of asthmatic children in this region and provide preliminary support for the use of air pollution monitors close to schools to track exposure and potential health risk in this population.

Pharmacotherapy of patients with mild persistent asthma: strategies and unresolved issues

In studies comparing regular versus on-demand treatment for patients with mild persistent asthma, on-demand treatment seems to have a similar efficacy on clinical and functional outcomes, but it does not suppress chronic airway inflammation or airway hyper-responsiveness (AHR) associated with asthma. Data on the efficacy of a continuous treatment with inhaled corticosteroids (ICS) in preventing the progression of asthma are conflicting. There is the possibility that patients without a regular treatment with ICS may develop a more severe asthma associated with airway structural changes (remodeling) and a progressive loss of lung function. However, the possible clinical and functional consequences of persistent, not controlled, airway inflammation in patients with asthma have to be established. Assessment of asthma control should include inflammatory outcomes, such as fraction of exhaled nitric oxide and sputum eosinophil counts. Until the relationships between symptoms, lung function tests, AHR, airway inflammation, exacerbations, and airway remodeling are clarified, regular treatment seems to be generally more appropriate than on-demand treatment to warrant a greater control of asthma. Select subgroups of patients with mild asthma who are well controlled by regular treatment might adopt the on-demand treatment plan as an intermediate step toward the suspension of controller medication. The increasing evidence for heterogeneity of asthma, the growing emphasis on asthma subphenotypes, including molecular phenotypes identified by omics technologies, and their possible implications for different asthma severity and progression and therapeutic response, are changing the paradigm of treating patients with asthma only based on classification of their disease severity to a pharmacological strategy more focused on the individual asthmatic patient. Pharmacological treatment of asthma is going toward a personalized approach.

Hand-held nitric oxide sensor NIOX MINO® for the monitoring of respiratory disorders

Measurements of exhaled nitric oxide have been proposed as a tool to improve the control of asthma and inflammatory airways disease, including the patient's response to anti-inflammatory treatment and to predict loss of control and to monitor compliance with treatment. Several techniques have been used to assess exhaled nitric oxide gas and the majority of studies have used the chemiluminescence method. More recently, a new hand-held electrochemical sensor NIOX MINO(®) has been developed. Here, we will review the use of the NIOX MINO for the study of respiratory disorders.

Control maintenance can be predicted by exhaled NO monitoring in asthmatic patients

BACKGROUND

Fractional exhaled nitric oxide (F(E)NO) is a marker of airway inflammation in asthma. Monitoring of such inflammation is currently not included in asthma guidelines and remains controversial. The hypothesis underlying the present study was that, F(E)NO could help assessing asthma control and, therefore, improve its management, by predicting loss of control in asthmatics.

METHODS

A total of 90 adult asthmatics were included in the study. Asthma control was evaluated according to ACQ. All patients underwent F(E)NO by chemiluminescent (EndoNO) and hand-held (MINO) devices, followed by lung function testing.

RESULTS

MINO was accurate as compared to EndoNO. F(E)NO was significantly increased in uncontrolled as compared to controlled asthmatics using both devices. F(E)NO measurement was able to predict control maintenance in controlled asthmatics in the absence of any change in their treatment. Indeed, using cut-off values of 31 and 40 ppb, the negative predictive values were 95 and 97% for EndoNO and MINO, respectively. EndoNO and MINO were also able to assess asthma control, although to a lesser extent.

CONCLUSIONS

These findings suggest that F(E)NO can predict the persistence of asthma control in controlled patients and may now be used in asthma management since it can accurately be measured by means of hand-held devices.