Fractional Exhaled Nitric Oxide Cutoff Value Research Articles

Clinical Value of FeNO for Pulmonary Hypertension Diagnosis in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease.

Objective To investigate the clinical value of fractional exhaled nitric oxide (FeNO) in the diagnosis of pulmonary hypertension (PH) in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Methods In this study, the medical records of AECOPD patients were retrospectively reviewed. The patients were divided into AECOPD and AECOPD + PH groups based on the absence or presence of PH. Moreover, FeNO and other indexes were compared between the two groups. The value of FeNO in diagnosing AECOPD with PH was determined using the ROC curve. Results A total of 83 patients were enrolled (56 in the AECOPD group and 27 in the AECOPD + PH group). The level of FeNO was significantly lower in the AECOPD + PH group than in the AECOPD group (P = 0.022). Moreover, FeNO level (25.22 ± 8.45 ppb) was higher in the mild PH subgroup than in the moderate (16.64 ± 5.67 ppb, P = 0.005) or severe (11.75 ± 2.36, P = 0.002) PH subgroups. FeNO level was positively correlated with C-reactive protein in AECOPD patients while negatively correlated with brain natriuretic peptide in the AECOPD + PH group. ROC analysis showed that the optimal cutoff value of FeNO in the diagnosis of AECOPD with PH was 24.5 ppb. Conclusion FeNO level at admission can act as an indicator for PH diagnosis in AECOPD patients.

Evaluation of Fractional Exhaled Nitric Oxide in Pediatric Asthma and Allergic Rhinitis.

Fractional exhaled nitric oxide (FeNO) is a non-invasive test for evaluating the degree of airway inflammation and for the diagnosis, evaluation, and treatment of asthma. We attempted to measure FeNO levels in Korean children with asthma and determine its cutoff value for diagnosing asthma. We enrolled 176 children and adolescents between the ages of 5 and 18 years, who visited for the evaluation of chronic cough, shortness of breath, and wheezing. Among them, 138 patients who underwent skin prick tests or inhalation Immuno CAP (UniCAP; Pharmacia, Uppsala, Sweden) tests for allergy testing together with a pulmonary function test were included. FeNO was measured using a NIOX MINO (Aerocrine AB, Solna, Sweden) instrument according to the American Thoracic Society/European Respiratory Society (ATS/ERS) guidelines. There were 29 patients with asthma, 43 with rhinitis, and 38 with asthma and allergic rhinitis. In the asthma group, FeNO levels significantly correlated with total immunoglobulin E (r = 0.572, p < 0.001), but did not show significant correlation with pulmonary function test parameters (forced vital capacity—FVC, forced expiratory volume in one second—FEV1, FEV1/FVC) or PC20 (provocative concentration of methacholine causing a 20% fall in FEV1). The FeNO cutoff values obtained in the asthma and asthma rhinitis groups were 16.5 ppb and 18.5 ppb, respectively. Hence, we provide a FeNO cutoff value according to the presence or absence of rhinitis in pediatric patients with asthma.

EVALUATION OF FRACTIONAL EXHALED NITRIC OXIDE IN INTERSTITIAL LUNG DISEASE

SESSION TITLE: Diffuse Lung Disease Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: October 18-21, 2020 PURPOSE: No established biomarkers are available to guide the treatment of chronic interstitial lung diseases (ILDs). Nitric oxide reflects the inflammation in the airway, and fractional exhaled nitric oxide (FeNO) is a non-invasive and reproducible biomarker in lung-disease diagnosis and treatment. Whether FeNO can help manage ILDs remains uncertain. This study aimed to determine the role of FeNO in ILDs and the association between FeNO and ILD subtype. METHODS: Fifty-three patients with ILDs were retrospectively recruited. Patient characteristics, FeNO values, pulmonary function test (PFT) data, and inflammatory markers values were obtained. RESULTS: This group of patients with ILDs had decreased vital capacity(VC)and total lung capacity(TLC) of 71.75 ± 17.58% and 75.27 ± 14.07%, respectively. The diffusion capacity of the lung for carbon monoxide (DLCO) also declined, with an average level of 38.15 ± 11.10%. The average FeNO value was 20.34 ± 9.97 ppb. According to the characteristics of chest computed tomography, patients were divided into usual interstitial pneumonia (UIP)-ILD (n = 24) and non-UIP-ILD (n = 29). The FeNO value in the UIP-ILD group was 12.58 ± 3.63 ppb. This value was significantly lower than that of the non-UIP-ILD group (26.62 ± 8.61 ppb, P<0.0001). However, no significant differences were observed in the PFT values, blood eosinophils, IgE, and systemic inflammatory markers between the two groups. According to the etiology, all patients with ILDs were divided into connective tissue diseases associated with interstitial lung disease (CTD-ILD) (n = 30) and non-CTD-ILD (n = 23). There were more female patients in CTD-ILD group compared to non-CTD ILD group and patients in CTD-ILD group were younger. With regard to the FeNO, PFT values, and systemic inflammatory markers, no significant differences were observed between groups. In the overall ILD population, FeNO level correlated with blood eosinophil (r = 0.3066, P=0.0333), but no statistically significant correlations were observed between the FeNO and blood eosinophil percentage, IgE or systemic inflammatory markers. Among the 29 patients with non-UIP-ILDs, 20 received systemic treatment like corticosteroid and they all responded well. The response rate was higher than that of UIP-ILD group (P<0.01). The FeNO cut-off value of 18.5 ppb showed a sensibility of 83.3% and a specificity of 95.8% in discriminating non-UIP-ILDs from UIP ILDs. CONCLUSIONS: Our study suggested the importance of FeNO test in patients with ILDs. High FeNO levels may indicate the need of systemic treatment, and FeNO can be a helpful biomarker for ILD management. CLINICAL IMPLICATIONS: FeNO can be a helpful biomarker for ILD management. High FeNO levels may indicate the need of systemic treatment in ILDs. DISCLOSURES: No relevant relationships by Xuefei Li, source=Web Response No relevant relationships by Gengpeng Lin, source=Web Response No relevant relationships by Zhaohui Zhang, source=Web Response

Assessment of the role of fractional exhaled nitric oxide in the diagnosis of asthma–chronic obstructive pulmonary disease overlap

Introduction Bronchial asthma and chronic obstructive pulmonary disease (COPD) are airway diseases with different etiology and a different presentation. Sometimes, asthma and COPD are present within the same patient as asthma–COPD overlap syndrome (ACOS). Aim To assess the role of fractional exhaled nitric oxide (FeNO) in the diagnosis of ACOS. Patients and methods A total of 60 patients with newly diagnosed stable COPD (n=20), bronchial asthma (n=20), and ACOS (n=20) were included from May 2016 to May 2017. COPD, asthma, and ACOS diagnosis depended on clinical history and examination and spirometric criteria according to GINA guidelines (2015). FeNO was measured and compared between the studied patients groups. The cutoff value for FeNO which can help in differentiating ACOS from COPD was determined. Results In the current study, the level of FeNO was significantly higher in the studied patients with ACOS in comparison with patients with COPD alone, and FeNO had significant positive correlation with sputum eosinophils % in patients with ACOS (P=0.013). Moreover, this study showed that the cutoff value of FeNO to differentiate ACOS from COPD was 20 parts per billion (with 80% sensitivity and 85% specificity and area under the curve=0.84). Conclusion This study showed that the measurement of FeNO can be used for early differentiation of ACOS from COPD alone for helping their proper management as early as possible.

Diagnostic value of FeNO and MMEF for predicting cough variant asthma in chronic cough patients with or without allergic rhinitis

Objective To evaluate the diagnostic value of fractional exhaled nitric oxide (FeNO) and maximum mid-expiratory flow (MMEF) for differentiating cough variant asthma (CVA) from chronic cough in patients with or without allergic rhinitis. Methods In total, 328 patients with chronic cough who underwent spirometry and FeNO testing were consecutively included in the retrospective analysis. Patients were divided into the CVA (n = 125) or NCVA (n = 203) groups according to the diagnostic criteria of CVA. Receiver operating characteristic (ROC) curves were established to assess the diagnostic efficiency and optimal cutoff points of FeNO and MMEF for the prediction of CVA. Results The optimal cutoff values of FeNO and MMEF to discriminate CVA from chronic cough were 24.5 ppb (AUC, 0.765; sensitivity, 69.60%; specificity 72.91%; PPV, 61.27%; NPV, 79.57%) and 66.2% (AUC, 0.771; sensitivity, 67.20%; specificity 78.33%; PPV, 65.63%; NPV, 79.50%). The optimal cutoff values of combining FeNO with MMEF to discriminate CVA from chronic cough were >22 ppb for FeNO and <62.6% for MMEF (AUC, 0.877). In patients with and without allergic rhinitis, the optimal cutoff point of FeNO to discriminate CVA from chronic cough was 24.5 ppb (AUC, 0.820) and 33.5 ppb (AUC, 0.707), respectively. Conclusions FeNO and MMEF might have greater value as negative parameters for differentiating CVA from chronic cough. Combining FeNO and MMEF provided a significantly better prediction than either alone. The diagnostic accuracy of FeNO for predicting CVA in chronic cough patients with allergic rhinitis was higher than in chronic cough patients without allergic rhinitis.

Values of fractional exhaled nitric oxide for cough-variant asthma in children with chronic cough.

Chronic cough is a common symptom in children. We wished to explore the value of fractional exhaled nitric oxide (FeNO) for cough-variant asthma (CVA) in children with chronic cough. This prospective cohort study was conducted in the Children's Hospital of Soochow University from January 2012 to December 2014. Children aged 6-14 years with a cough of duration >4 weeks were enrolled. They underwent FeNO measurement, sputum cytology and pulmonary function tests. A total of 115 patients and 25 healthy controls were evaluated. For the diagnosis of CVA, the optimal FeNO cutoff value was 25 ppb with a sensitivity of 84.0%, specificity of 97.1%, positive predictive value of 97.5%, and negative predictive of being 81.4%. The FeNO level had a significant correlation with eosinophil count in sputum (P<0.05). FeNO level in CVA was decreased significantly after treatment (P=0.001). In children, FeNO measurement might be an excellent method for diagnosing CVA with high sensitivity and specificity.

Clinical utility of fractional exhaled nitric oxide and blood eosinophils counts in the diagnosis of asthma-COPD overlap.

BackgroundAsthma–COPD overlap (ACO) is difficult to diagnose because it is characterized by persistent airflow limitation, and patients present with several manifestations that are usually associated with both asthma and COPD. In this retrospective study, we aimed to evaluate the diagnostic accuracy of fractional exhaled nitric oxide (FeNO) and blood eosinophil counts for the clinical diagnosis of ACO.Patients and methodsA total of 121 patients were divided into two study groups, COPD alone or ACO, which was based on criteria from the joint document by the Global Initiative for Asthma and the Global initiative for chronic Obstructive Lung Disease. From July 2014 to April 2017, FeNO levels and blood eosinophil counts were measured in specimens from patients naïve to inhaled corticosteroids (ICS) and those using ICS. Receiver operating characteristic curve analysis was used to determine the cutoff values of FeNO and blood eosinophil levels that provided the best differential diagnosis between ACO and COPD.ResultsAmong a total of 121 patients, 65 patients were diagnosed with COPD and 56 patients with ACO. The FeNO level was higher in patients with ACO than in patients with COPD (median 24.5 vs 16.0 ppb, respectively; P<0.01). Among patients naïve to ICS, the area under the receiver operating characteristic curve of FeNO values was 0.726, and the optimal diagnostic cutoff level of FeNO was 25.0 ppb, with 60.6% sensitivity and 87.7% specificity for differentiating ACO from COPD. FeNO (≥25.0 ppb) combined with blood eosinophil counts (≥250/μL) showed 96.1% specificity.ConclusionThese results demonstrate that the FeNO level combined with blood eosinophil count is useful for the differential diagnosis between ACO and COPD.

Phenotype classification using the combination of lung sound analysis and fractional exhaled nitric oxide for evaluating asthma treatment

BackgroundWe report the utility of combining lung sound analysis and fractional exhaled nitric oxide (FeNO) for phenotype classification of airway inflammation in patients with bronchial asthma.We investigated the usefulness of the combination of the expiration-to-inspiration sound power ratio in the mid-frequency range (E/I MF) of 200–400 Hz and FeNO for comprehensively classifying disease type and evaluating asthma treatment. MethodsA total of 233 patients with bronchial asthma were included. The cutoff values of FeNO and E/I MF were set to 38 ppb and 0.36, respectively, according to a previous study. The patients were divided into 4 subgroups based on the FeNO and E/I MF cutoff values. Respiratory function, the percentages of sputum eosinophils and neutrophils, and patient background characteristics were compared among groups. ResultsRespiratory function was well controlled in the FeNO low/E/I MF low group (good control). Sputum neutrophil was higher and FEV1,%pred was lower in the FeNO low/E/I MF high group (poor control). History of childhood asthma and atopic asthma were associated with the FeNO high/E/I MF low group (insufficient control). The FeNO high/E/I MF high group corresponded to a longer disease duration, increased blood or sputum eosinophils, and lower FEV1/FVC (poor control). ConclusionsThe combination of FeNO and E/I MF assessed by lung sound analysis allows the condition of airway narrowing and the degree of airway inflammation to be assessed in patients with asthma and is useful for evaluating bronchial asthma treatments.

Exhaled nitric oxide helps discriminating asthmatic children with and without positive specific IgE to aeroallergens.

Aeroallergen sensitization may predict higher fractional exhaled nitric oxide (FeNO) levels. We evaluate cut-off values of FeNO in asthmatic children with and without positive specific immunoglobulin E (IgE) to at least one of 5 aeroallergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae, cat, dog, and cockroach). 564 patients with asthma and allergic rhinitis (AR) aged 5 to 18 years were enrolled into two groups. Sensitized group included 378 children with positive IgE to at least one of 5 inhaled allergens. Non-sensitized group included 186 children. Pulmonary function tests, FeNO, eosinophil counts, and IgE levels were examined. Patients were divided into preschool age (5~6 years old), elementary school children (7~11 years old) and adolescents (12~18 years old). In preschool children, FeNO≥15.5 ppb differentiates between non-sensitized and sensitized groups. (sensitivity 54.3%; specificity 87.5%; positive predictive value (PPV) 86.2%; negative predictive value (NPV) 57.1%; area under receiver operating characteristic curve (AUC) 0.72) Among elementary school children, the cut-off value of FeNO≥19.5 ppb showed sensitivity 66.4%; specificity 85.8%; PPV 90.5%; NPV 55.7%; AUC 0.81. In adolescents, FeNO≥27.5 ppb showed sensitivity 60.2%; specificity 85.4%; PPV 91.2%; NPV 46.1%; AUC 0.76. In asthmatic children, aeroallergen sensitization appears to contribute to higher FeNO levels than those not sensitized. Cut-off values of FeNO which well discriminate asthmatic children with and without aeroallergen sensitization should be chose according to different ages.

Association between fractional exhaled nitric oxide (FeNO) cutoff values (25 ppb) and risk factors of cough.

Cough is among the most common symptoms for patients to seek medical attention. The purpose of this study is to evaluate the association between fractional exhaled nitric oxide (FeNO) cutoff values (25 ppb) and risk factors related to cough, hoping to evaluate the feasibility of the FeNO cut point values (25 ppb) for clinical prediction of cough in etiology. In 107 adult patients with acute, subacute, or chronic cough, the FeNO, forced expiratory volume for 1 second (FEV1), forced vital capacity (FVC), blood routine (white blood cell and neutrophil), immunoglobulin E (IgE), lymphocyte eosinophils, and hemoglobin were measured. The Student's t-test was used to test the differences of FeNO levels compared with FEV1/FVC, lymphocyte, and hemoglobin level. For evaluating the correlation of FeNO levels with IgE, eosinophil, blood routine, pulmonary infection, and smoking status, the chi-square test was performed. FeNO cutoff value (25 ppb) significantly correlated with serum IgE (P < .0001) between ≥200 IU/mL and <200 IU/mL level, eosinophil (P = .039) between ≥5% and <5% level, lymphocyte percentage (P = .032) and the ratio of FEV1/FVC (P = .032), while weakly correlated with pulmonary infection, blood routine (white blood cell and neutrophil), hemoglobin, and smoking. The cutoff values of FeNO (≥25 ppb or <25 ppb) are useful for etiological detection of cough with high sensitivity.

Fractional exhaled nitric oxide for identification of uncontrolled asthma in children

To determine the utility of Fractional Exhaled Nitric Oxide (FENO) in the identification of uncontrolled asthma in children on therapy, and to identify its cut-off value for determining asthma control. 207 children (age 5-15 y) with physician-diagnosed asthma on therapy with at least 12 months follow up were enrolled. Spirometry and FENO measurements were performed. Asthma control was assessed as per GINA guidelines. Sensitivity and specificity of various cut-off values of FENO (15 ppb, 20 ppb, 25 ppb, 30 ppb) for identification of status of control of asthma were calculated. 156 (75%) children had uncontrolled or partly controlled asthma and 51 children were assessed to have controlled asthma. Median (IQR) FENO in children with controlled and uncontrolled asthma was 16 (11-23) ppb and 13 (11-25) ppb, respectively (P=0.26). No FENO cut-off had a reasonable combination of sensitivity and specificity to discriminate between controlled and uncontrolled asthma. FENO, in itself, does not have good discriminatory value in assessment of controlled and uncontrolled asthma in children on asthma therapy.

Clinical value of fractional exhaled nitric oxide level in predicting bronchial hyperreactivity in asthmatic children

Objective To evaluate the clinical value of fractional exhaled nitric oxide (FeNO) level in asthmatic children to predict bronchial hyperresponsiveness by analyzing the correlation between fraction of exhaled nitric oxide and bronchial provocation test. Methods One hundred and fourteen asthma outpatients of Shengjing Hospital were enrolled, FeNO levels, spirometry and bronchial provocation test were measured. Results In the bronchial provocation test, there were 33 positive and 81 negative cases.The positive group had a significantly higher FeNO levels than the negative ones(19.0×10-9 vs.16.0×10-9, P=0.000). By the ROC curve, the best FeNO cut-off value to predict bronchial hyperresponsiveness was 38.5×10-9 with high specificity(92.6%) but relatively low sensitivity(36.4%). There was no relationship between methacholine provocative dose causing a 20% fall in FEV1(PD20-FEV1) and the level of FeNO. Conclusion FeNO level has important predicting value for bronchial hyperreactivity in children with asthma.The level of FeNO >38.5×10-9 has high predictive value in asthmatic children with bronchial hyperreactivity. Key words: Exhaled nitric oxide; Methacholine bronchial provocation test; Asthma; Children

Biomarker-based detection of asthma-COPD overlap syndrome in COPD populations.

Asthma–chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) was proposed by the science committees of both Global Initiative for Asthma (GINA) and Global Initiative for Chronic Obstructive Lung Disease (GOLD). However, the definition of ACOS has remained unclear all over the world, and the prevalence rate of ACOS is basically dependent on the patient’s symptoms or the physician’s opinion, based on questionnaire testing. In the current case report, we investigated the prevalence rate of COPD patients with high levels of fractional exhaled nitric oxide (FENO) or immunoglobulin E (IgE) as candidate markers of ACOS in COPD, as a multicenter, cross-sectional study. Outpatients with COPD were enrolled from Tohoku University Hospital, Sendai, Japan, and five hospitals (Tohoku University Hospital, Sendai, Japan; NTT East Tohoku Hospital, Sendai, Japan; Wakayama Medical University Hospital, Kimiidera, Japan; Hiraka General Hospital, Yokote, Japan; Iwate Prefectural Isawa Hospital, Oshu, Japan) with pulmonary physicians from March 1, 2013 to February 28, 2014. When they were estimated using 35 ppb as the cutoff value of FENO, the prevalence rate of ACOS was 16.3% in COPD. When estimated by both FENO and IgE, the high-FENO/high-IgE group was 7.8% in COPD. To the best of our knowledge, this study is the first to detect the prevalence rate of ACOS in COPD populations by using objective biomarkers. The results from the current study should be useful to identify the subgroup requiring early intervention by inhaled corticosteroids/long-acting beta agonist combination in COPD in order to improve the long-term management for ACOS.

Utility of tools for the assessment of asthma control in childhood asthma

Purpose: The goal of asthma control is to maintain well-controlled state. In this study, we investigated whether childhood asthma control test (C-ACT) may reflect lung function and whether fractional exhaled nitric oxide (FeNO) can be used to improve the accuracy of C-ACT in reflecting the asthma control level. Methods: We reviewed the medical records of 155 patients with asthma underwent lung function tests and C-ACT upon visiting our outpatient clinic. We compared lung function test results according to the C-ACT score stratified by atopy and also examined FeNO according to C-ACT and the Global Initiative for Asthma (GINA) guidelines. The diagnostic accuracy of well-controlled asthma by C-ACT, FeNO, and C-ACT+FeNO was examined. We also calculated the cutoff value of FeNO and C-ACT for well-controlled asthma. Results: Peak expiratory flow (PEF) showed a significant correlation with the C-ACT score. Stratified by atopy, PEF, and forced expiration in one second (FEV1) showed significant correlations with the C-ACT score in the atopic asthma group. There was no difference in FeNO between subjects with C-ACT≥20 and <20, but FeNO was significantly higher in the uncontrolled asthma according to the GINA guidelines. The diagnostic accuracy of well-controlled asthma was higher when FeNO was combined with the C-ACT score than C-ACT or FeNO. Our study showed that the cutoff values of C-ACT and FeNO 19 and 18.3 ppb (parts per billion), respectively, for well-controlled asthma. Conclusion: C-ACT showed a significant correlation with PEF, and atopic asthma group showed significant correlations with PEF and FEV1. A combination of C-ACT with FeNO might reflect asthma control status more accurately. (Allergy Asthma Respir Dis 2015;3:261-266)

Fractional exhaled nitric oxide in bronchial inflammatory lung diseases

To explore the change of fractional exhaled nitric oxide (FeNO) and its correlation with forced expiratory volume in the first second (FEV1), the first second forced expiratory volume percentage of forced vital capacity (FEV1/FVC) in bronchial asthma and chronic obstructive pulmonary disease (COPD). FeNO, FEV1 and FEV1/FVC were measured in 57 suspected asthmatics (21 acute onsets, 12 non-acute and 24 non-asthma), 38 COPD patients (25 acute exacerbations and 13 stable stages) and 26 healthy subjects. In the 57 suspected asthmatic patients, when the optimal cut off value of FeNO was 20.15 PPb, which was used to diagnose asthma and differentiate asthma and non-asthma, the positive predictive value, the negative predictive value, the sensitivity and the specificity was 94.1%, 95.7%, 97.0%, and 91.7% respectively. There was significant difference in the FeNO level between the 33 asthmatics and 26 healthy subjects (P<0.05). There was also significant difference in the FeNO level between the acute onset and the non-acute (P<0.05), but not in the FEV1 and FEV1/FVC level (both P>0.05). There was no significant correlation between FeNO and FEV1, FEV1/FVC in patients with asthma (r=-0.186, -0.236, both P>0.05). There was significant difference in the levels of FeNO, FEV1 and FEV1/FVC between the 38 COPD patients and the 26 healthy subjects (all P<0.05), and also between the 25 acute exacerbations and 13 stable COPDs (all P<0.05), but not between the 13 stable COPDs and 26 healthy subjects (all P>0.05). FeNO was not correlated with FEV1 and FEV1/FVC level in COPD patients (r=-0.167, -0.285, both P>0.05). FeNO level is increased obviously in patients with asthma. The optimal cut off value of FeNO at 20.15 PPb can differentiate asthma and non-asthma with high sensitivity and specificity. FeNO is higher for the acute onset than non-acute, which may be useful to evaluate the control degree. FeNO level is increased in COPD patients in the acute exacerbations, but there is no change in stable COPD patients compared with the healthy subjects.

Usefulness of impulse oscillometry and fractional exhaled nitric oxide in children with Eosinophilic bronchitis

Eosinophilic bronchitis (EB) is a common cause of chronic cough. Although EB shares many immunopathologic features with asthma, it does not show airway hyperresponsiveness or reversible airway obstruction by spirometry. Compared to healthy children without pulmonary disease, we hypothesized that EB patients would demonstrate abnormal pulmonary function and inflammation with impulse oscillometry (IOS) and fractional exhaled nitric oxide (FeNO), which are more sensitive tests of these parameters than spirometry. A total of 232 children with asthma, 109 with EB, and 115 control subjects were enrolled. We compared pulmonary function parameters and FeNO levels among the three groups. Additionally, we designated a screening cutoff value of FeNO combined with IOS parameters to distinguish EB from the control group, and identify which children with EB have more asthmatic characteristics. By IOS, the bronchodilator response of the EB and asthma groups increased significantly compared to controls for both reactance at 5 Hz (Δ X5) and reactance area (Δ AX) (P < 0.0001). Cutoff values to distinguish EB from controls were a Δ X5 of -20% (sensitivity, 77.5%; specificity, 49.6%), and Δ AX of -30% (sensitivity, 75.0%; specificity, 46.0%), when the FeNO is 20 ppb. Reversible airway obstruction in IOS and elevated FeNO levels can be detected in children with EB. This would support that EB in children shows airway characteristics similar to those of asthma, and that a continuum exists between asthma and EB.

Usefulness of Impulse Oscillometry In Children With Eosinophilic Bronchitis

FEBRUARY 2012 AB4 Abstracts S A T U R D A Y 13 Usefulness of Impulse Oscillometry In Children With Eosinophilic Bronchitis Y. Kim, K. Kim, J. Baek, H. Park, H. Lee, M. Sohn, K. Kim; Department of Pediatrics and Institute of Allergy, Severance Biomedical Science Institute, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, REPUBLIC OF KOREA, Kwandong University College of Medicine, Goyang, REPUBLIC OF KOREA. RATIONALE: Eosinophilic bronchitis (EB) has been shown to resolve, whereas it has been shown to progress to asthma in some patients, despite treatment with inhaled steroids. It is controversial whether EB is a pre-form of asthma.We evaluated pulmonary function by impulse oscillometry (IOS) and airway inflammation by measuring fractional exhaled nitric oxide (FeNO) of children with EB in comparison of those with asthma and healthy children as a control. METHODS: A total of 232 children with asthma, 109 with EB, and 115 control subjects were enrolled. We compared pulmonary function test parameters and FeNO levels among three subject groups, and designated a cutoff value of FeNO combined with IOS parameters to distinguish EB from the control group. RESULTS: Pulmonary function and bronchodilator response for EB in spirometry were of normal range as well as for the control. In IOS, the percentage change in reactance at 5 Hz (D X5) and the percentage change in reactance area (DAX) of the EB as well as the asthma groups decreased significantly compared to the control (P < .0001). A cutoff value to distinguish EB from control was D X5 is220% (sensitivity, 77.5%; specificity, 49.6%), and D AX is 230% (sensitivity, 75.0%; specificity, 46.0%) when FeNO is 20 ppb. CONCLUSIONS: Reversible airway obstruction in IOS and elevated FeNO levels can be useful for evaluation of EB in children. This would support that EB shows airway characteristics similar to those of asthma.

Values of fractional exhaled nitric oxide in the diagnosis of chronic cough

To evaluate the diagnostic value of fractional exhaled nitric oxide (FeNO) in the diagnosis of chronic cough. A total of 106 subjects with chronic cough and normal chest radiographs were recruited from October 2009 to September 2010. Based on the management guidelines of the Chinese Respiratory Society for cough, the golden standard methods were used to make the definite diagnosis of chronic cough, including sputum cell counts, pulmonary function tests, bronchial hyperresponsiveness, 24-h esophageal pH monitoring, skin pricking test and serum immunoglobulin E. All subjects received a FeNO test by a NIOXMINO analyzer. The values of FeNO to diagnose cough variant asthma (CVA) from chronic cough and EB from non-asthma cough were respectively assessed by the receiver operating characteristic (ROC) curves. Among them, the definite diagnoses were cough variant asthma (CVA, n = 39), eosinophilic bronchitis (EB, n = 30) and other causes (n = 37). The FeNO levels in CVA [(54 ± 21) ppb)] (1 ppb = 1 × 10(9) mol/L) were significantly higher than those in EB [(34 ± 17) ppb, P < 0.01] and other causes [(21 ± 10) ppb, P < 0.01]. And the FeNO levels in EB were higher than those in other causes (P < 0.01). To diagnose CVA from chronic cough, the optimal FeNO cutoff value was 40 ppb with a sensitivity of 75%, a specificity of 86%, a positive predictive value of 77%, a negative predictive value of 86% and an accuracy of 81%. To diagnose EB from non-asthma chronic cough, the optimal FeNO cutoff value was 31 ppb with a sensitivity of 63%, a specificity of 92%, a positive predictive value of 88%, a negative predictive value of 92% and an accuracy of 72% respectively. There are significant differences between the FeNO levels of different causes of chronic cough. A marked elevation of FeNO level helps to make a final diagnosis of CVA or EB. FeNO test is useful for making the diagnosis and differential diagnosis of chronic cough in clinic practices.

Usefulness of Exhaled Nitric Oxide for Diagnosing Asthma

Rationale. A standard asthma diagnosis is made based on clinical history, reversibility of airway obstruction, and bronchial hyperresponsiveness. Fractional exhaled nitric oxide (FeNO) is a noninvasive airway inflammatory marker that has been suggested as a diagnostic tool for asthma. The aim of this study was to establish a FeNO cut-off value for asthma diagnosis. Methods. One hundred and fourteen consecutive adult patients (mean age 34 ± 13 years) reporting symptoms consistent with asthma, with normal spirometric parameters and a negative bronchodilator test, were included in the study. All underwent a methacholine challenge test following the five-breath dosimeter protocol. FeNO was measured with a portable device (NioxMino, Aerocrine AB, Sweden) just before the methacholine challenge. The sensitivity, specificity, and diagnostic performance of FeNO measurement were calculated. Results. Thirty-five out of the 114 patients (30.7%) were diagnosed with asthma. A positive methacholine challenge was associated with higher FeNO levels and with lower forced expiratory volume in one second (FEV1) at baseline. No correlation was found between methacholine provocative concentration causing a decrease of 20% in FEV1 (PC20) and FeNO levels. A receiver-operating characteristic curve was constructed for FeNO levels (area under the curve [AUC]: 0.762; 95% confidence interval [CI]: 0.667-0.857; p < .001). The FeNO cut-off point with maximal specificity and sensitivity for asthma diagnosis was 40 ppb. Conclusions. Patients with confirmed asthma showed higher FeNO levels. A cut-off value of 40 ppb was calculated as the most efficient for asthma diagnosis in our population. The use of FeNO measurement may be a helpful tool to rule out a diagnosis of asthma, especially in patients in whom a methacholine challenge is not feasible or available.