• Tuberculosis and Respiratory Diseases
• /
• v.83 no.1
• /
• pp.42-50
• /
• 2020

Background: Fractional exhaled nitric oxide (FeNO) is regarded as a potential biomarker for identifying eosinophilic inflammation. We aimed to evaluate the clinical implication of FeNO and its influence on inhaled corticosteroids (ICS) prescription rate in Korean chronic obstructive pulmonary disease (COPD) patients. Methods: FeNO level and its association with clinical features were analyzed. Changes in the prescription rate of ICS before and after FeNO measurement were identified. Results: A total of 160 COPD patients were divided into increased (≥25 parts per billion [ppb], n=74) and normal (<25 ppb, n=86) FeNO groups according to the recommendations from the American Thoracic Society. Compared with the normal FeNO group, the adjusted odds ratio for having history of asthma without wheezing and with wheezing in the increased FeNO group were 2.96 (95% confidence interval [CI], 1.40-6.29) and 4.24 (95% CI, 1.37-13.08), respectively. Only 21 out of 74 patients (28.4%) with increased FeNO prescribed ICS-containing inhaler and 18 of 86 patients (20.9%) with normal FeNO were given ICS-containing inhaler. Previous exacerbation, asthma, and wheezing were the major factors to maintain ICS at normal FeNO level and not to initiate ICS at increased FeNO level. Conclusion: Increased FeNO was associated with the history of asthma irrespective of wheezing. However, FeNO seemed to play a subsidiary role in the use of ICS-containing inhalers in real-world clinics, which was determined with prior exacerbation and clinical features suggesting Th2 inflammation.

• Tuberculosis and Respiratory Diseases
• /
• v.71 no.2
• /
• pp.106-113
• /
• 2011

Background: While asthma control is defined as the extent to which the various manifestations of asthma are reduced by treatment, current guidelines of asthma recommend assessment of asthma control without consideration of airway inflammation. Our aim was to investigate the relationships between fractional exhaled nitric oxide (FeNO), a reliable marker of airway inflammation, and levels of asthma control in patients treated with inhaled corticosteroids (ICS). Methods: We enrolled 71 adult patients with asthma who had been treated with ICS for more than four months. FeNO was measured and spirometry was performed at the time of enrollment. Asthma control was assessed (a) by the physician based on the Global Initiative for Asthma guidelines, (b) by the patients, and (c) by using the Asthma Control Test (ACT). Statistical analyses were done to analyze the relationships between (i) FeNO and (ii) measures of asthma control and clinical indices for asthma manifestations. Results: There was no significant difference in FeNO levels between the three groups according to levels of asthma control (controlled, partly controlled and uncontrolled) as determined by the physician (p=0.81), or by the patients (p=0.81). In addition, FeNO values were not significantly correlated with the ACT scores (r=0.031, p=0.807), while FeNO showed a correlation with peripheral blood eosinophil counts (p<0.001). Conclusion: These findings demonstrate that FeNO levels are not associated with measures of asthma control in patients treated with ICS. Information on airway inflammation from FeNO concentrations seems to be unrelated to levels of asthma control

• Tuberculosis and Respiratory Diseases
• /
• v.74 no.1
• /
• pp.7-14
• /
• 2013

Background: Fractional exhaled nitric oxide (FeNO) can be measured easily, rapidly, and noninvasively for the assessment of airway inflammation, particularly mediated by eosinophil, such as asthma. In bronchiectasis (BE), the pathogenesis has been known as chronic airway inflammation and infection with abnormal airway dilatation; however, there are little studies to evaluate the role of FeNO in BE. Methods: From March 2010 to February 2012, 47 patients with BE, diagnosed by high resolution computed tomography (HRCT), performed FeNO, compared with asthma and chronic obstructive pulmonary disease (COPD). All patients carried out a complete blood count including eosinophil count, chemistry, sputum examination, and spirometry, if indicated. A retrospective analysis was performed to elucidate the clinical role of FeNO in BE patients. Results: The mean FeNO levels in patients with BE was $18.8{\pm}1.5$ part per billion (ppb), compared to $48.0{\pm}6.4$ and $31.0{\pm}4.3$ in those with asthma and COPD, respectively (p<0.001). The FeNO levels tended to increase along with the disease severity scores by HRCT; however, it was statistically not significant. FeNO in BE with a co-infection of nontuberculous mycobacteria was the lowest at $17.0{\pm}3.5$ ppb among the study population. Conclusion: FeNO in BE was lower than other chronic inflammatory airway diseases, particularly compared with asthma. For clinical application of FeNO in BE, more large-scaled, prospective studies should be considered.

• Tuberculosis and Respiratory Diseases
• /
• v.83 no.3
• /
• pp.234-241
• /
• 2020

Background: The fractional exhaled nitric oxide (FENO) test is useful in asthma patients. However, a few studies on its usefulness in chronic obstructive pulmonary disease (COPD) patients have been reported. We analyzed the FENO level distribution and clinical characteristics according to the FENO level in COPD patients. Methods: From December 2014 to June 2019, COPD patients who underwent pulmonary function and FENO tests at Chonnam National University Hospital were retrospectively evaluated for FENO, comorbidities, asthma history, blood eosinophil, and pulmonary function test. The high FENO group was defined as those with FENO level>25 parts per billion (ppb). Results: A total of 849 COPD patients (mean age, 70.3±9.4 years) were included. The mean forced expiratory volume at 1 second was 66.5±21.7% and the mean FENO level was 24.3±20.5 ppb. Patients with FENO ≤25 ppb were 572 (67.4%) and those with FENO >25 ppb were 277 (32.6%). Blood eosinophil percentage was significantly higher (4.2±4.8 vs. 2.7±2.5, p<0.001) in patients with the high FENO group than the low FENO group. The high FENO group revealed a significantly higher frequency of patients with blood eosinophil percentage >3% (46.9% vs. 34.8%, p=0.001) and asthma history (25.6% vs. 8.6%, p<0.001) than the lower FENO group. Asthma history, blood eosinophil percentage >3%, and positive bronchodilator response (BDR) were independent risk factors for the high FENO level (adjusted odds ratio [aOR], 3.85; p<0.001; aOR, 1.46; p=0.017; and aOR, 1.57, p=0.034, respectively) in the multivariable analysis. Conclusion: The FENO level distribution varied in COPD patients and the mean FENO value was slightly elevated. Asthma history, eosinophil percent, and positive BDR were independent risk factors for the high FENO level.

• Ceramist
• /
• v.22 no.1
• /
• pp.70-81
• /
• 2019

Breath analysis is rapidly evolving as a non-invasive disease recognition and diagnosis method. Metal oxide gas sensors are one of the most ideal platforms for realizing portable, hand-held breath analysis devices in the near future. This paper reviewed the recent developments in metal oxide gas sensors detecting exhaled biomarker gases such as nitric oxides, acetone, ammonia, hydrogen sulfide, and hydrocarbons. Emphasis was placed on strategies to tailor sensing materials/films capable of highly selective and sensitive detection of biomarker gases with negligible cross-response to ethanol, the major interfering breath gas. Specific examples were given to highlight the validity of the strategies, which include optimization of sensing temperature, doping additives, utilizing acid-base interaction, loading catalysts, and controlling gas reforming reaction. In addition, we briefly discussed the design and optimization method of gas sensor arrays for implementing the simultaneous assessment of multiple diseases. Breath analysis using high-performance metal oxide gas sensors/arrays will open new roads for point-of-care diagnosis of diseases such as asthma, diabetes, kidney dysfunction, halitosis, and lung cancer.

• Clinical and Experimental Pediatrics
• /
• v.64 no.2
• /
• pp.60-67
• /
• 2021

Eosinophils are a type of granulocyte with eosinophilic granules in the cytoplasm that play an important role in allergic and parasitic diseases. Eosinophils are important in the pathogenesis of asthma, and many studies have examined the relationship between them. In allergic eosinophilic asthma, eosinophils act not only as important effector cells but also as antigen-presenting cells in allergic inflammatory reactions. In nonallergic eosinophilic asthma, type 2 innate lymphoid cells in the airways play an important role in eosinophil activation. Direct methods, including bronchial biopsy, bronchoalveolar lavage, and the induced sputum test, are used to evaluate eosinophilic inflammatory reactions in patients with asthma, however, because of difficulty with their implementation, they are sometimes replaced by measurements of blood eosinophils, fraction of exhaled nitric oxide, and serum periostin level. However, these tests are less accurate than direct methods. For the treatment of patients with severe eosinophilic asthma, anti-interleukin-5 preparations such as mepolizumab, reslizumab, and benralizumab have recently been introduced and broadened the scope of asthma treatment. Although eosinophils are already known to play an important role in asthma, we expect that further studies will reveal more details of their action.

• Clinical and Experimental Pediatrics
• /
• v.46 no.3
• /
• pp.284-290
• /
• 2003

Purpose : A new airway inflammatory marker, exhaled nitric oxide(ENO) has been reported to correlate with bronchial hyperresponsiveness(BHR) and atopy. The purpose of this study was to analyze the relationship of ENO with BHR or atopy in patients with asthma and with allergic rhinitis. Methods : The subjects consisted of 55 children with asthma, 17 with allergic rhinitis, and 14 healthy controls. The asthma group was subdivided into the atopic asthma group(n=37) and the nonatopic asthma group(n=18) and the allergic rhinitis group into BHR group(n=7) and non-BHR group(n=10). All were investigated with spirometry and measurements of ENO concentration. The correlations between ENO concentration and both methacholine $PC_{20}$(provocative concentration causing a 20% decrease in forced expiratory volume in one second) and the number of allergen skin test positivity were analyzed. Results : ENO concentrations of both asthma and allergic rhinitis groups were significantly greater than that of control(P<0.01). ENO concentration of atopic asthma was significantly greater than that of nonatopic asthma(P<0.01). In allergic rhinitis, ENO concentration did not differ according to the presence or absence of BHR(P=0.50). ENO concentrations correlated significantly with the number of skin test positivity(r=0.32, P=0.02) or methacholine $PC_{20}$(r=-0.38, P<0.01) in asthma group, but not in the allergic rhinitis group(r=0.42, P=0.09; r=-0.06, P=0.83). Conclusion : In asthma patients, some pathogenetic mechanisms associated with atopy and BHR seem to influence ENO concentration. In allergic rhinitis patients, some factors other than BHR may be important in determining ENO concentration.

• Clinical and Experimental Pediatrics
• /
• v.51 no.2
• /
• pp.181-187
• /
• 2008

Purpose : Asthma is characterized by reversible airway obstruction and bronchial hyperresponsiveness result from airway inflammation. Fraction of nitric oxide in expired air (FeNO) has recently been investigated as a noninvasive measure of airway inflammation. FeNO has been reported to correlate with induced sputum eosinophilia and methacholine challenge test that it is represent severity of asthma. The purpose of this study was to analyze the relationship of FeNO with pulmonary function tests in patients with intermittent asthma. Methods : Eighty children included in this study were diagnosed as asthma from April through August, 2005 in Department of Pediatrics, College of Medicine, Kyunghee University. They aged from 4 to 15 years who were able to conduct spirometry and FeNO monitoring. They did not have upper respiratory tract infection and did not use an asthma controller which contain corticosteroids within 4 weeks. Pulmonary function test was done and FeNO was measured with online tidal breathing method using a chemiluminescence NO analyzer (CLD 88 sp, Eco Medics, Duernten, Switzerland). The correlations between pulmonary function test and FeNO were analyzed using Spearman correlation coefficient method. Results : The mean of FeNO of subject was 16.88 parts per billion (ppb). The mean of forced expiratory volume in 1 second ($FEV_1$) was $0.890{\pm}0.455L$ and forced vital capacity (FVC) was $1.071{\pm}0.630L$. The mean of predicted $FEV_1%$ ($FEV_1%pred$) was $98.39{\pm}34.27%$ and $FEV_1/FVC$ was $88.53{\pm}19.49$. FeNO was significantly correlate with $FEV_1$ (r=0.345, P<0.01) and FVC (r=0.244, P<0.05). FeNO did not correlate with $FEV_1%pred$ or $FEV_1/FVC$. Conclusion : The measurement of FeNO could be a useful marker in the management of childhood asthma and it is evolving to provide a complementary role alongside existing pulmonary function test. We propose that measuring technique and establishment of normal reference range are important area for future research.

• Tuberculosis and Respiratory Diseases
• /
• v.59 no.4
• /
• pp.361-367
• /
• 2005

Background : Differential diagnosis of lymphocytic pleural effusion is difficult even with many laboratory findings. Nitric oxide(NO) level is higher in the sputum or exhaled breath of patients with active pulmonary tuberculosis than in those without tuberculosis. In addition, there are some reports about the increased level of NO metabolites in body fluids of cancer patients. However, there is no data on the NO levels in the pleural fluid of patients with tuberculous pleurisy. Method : The serum and pleural fluid NO in the patients with acute lymphocytic pleural effusion were analyzed. Results : Of total 27 patients, there were 14 males and average age of patients was 48 years. The final diagnosis was tuberculous pleurisy in 17 cases and malignant pleural effusion in 10. The pleural fluid NO level was $540.1{\pm}116.4{\mu}mol$ in the tuberculous pleurisy patients and $383.7{\pm}71.0{\mu}mol$ in the malignant pleural effusion patients. The serum NO level was $624.7{\pm}142.0{\mu}mol$ in tuberculous pleurisy patients and $394.4{\pm}90.4{\mu}mol$ in malignant pleural effusion patients. There was no significant difference in the serum and pleural fluid NO level between the two groups. The NO level in the pleural fluid showed a significant correlations with the pleural fluid neutrophil count, the pleural fluid/serum protein ratio, and pleural fluid/serum albumin ratio (p<0.05 in each). The protein concentration, leukocyte and lymphocyte count in the pleural fluid were significantly higher in the tuberculous pleurisy patients than the malignant pleural effusion patients (p<0.05 in each). Conclusion : NO is not a suitable marker for a differential diagnosis of lymphocytic pleural effusion. However, the NO level in the pleural fluid might be associated with the neutrophil recruitment and protein leakage in the pleural space.

• Journal of Environmental Health Sciences
• /
• v.46 no.6
• /
• pp.685-693
• /
• 2020

Objectives: Recent data indicate that sensitization to mold contributes to the severity and persistence of asthma. The aim of this study was to investigate relationships between indoor mold concentrations and pulmonary function parameters in asthmatic children with mold sensitization. Methods: Asthmatic subjects who had a positive result in skin-prick testing to more than one mold allergen, such as Alternaria, Aspergillus, or Penicillium, were enrolled. Their pulmonary function and methacholine challenge test results were collected. Measurements of blood eosinophil, serum IgE, and fractional exhaled nitric oxide (FeNO) were taken. Indoor levels of VOC, CO2, PM10 and PM2.5 in each subject's house were measured. We counted mold and bacteria colonies from the subjects' house air samples. Results: The mean levels of FEV1, FVC, FEV1/FVC, and FEF25-75 were 82.8±19.7, 87.3±17.9, 85.8±8.3, and 82.3±28.9%, respectively. The mean FeNO level was 19.8±11.2 ppb and the geometric mean (range of one SD) of methacholine PC20 was 3.99 mg/mL (0.67-23.74 mg/mL). The average indoor air pollutant levels were below the recommended levels set by the Ministry of Environment for multiplex buildings. Indoor mold levels showed a significant inverse correlation with methacholine PC20, but not with the baseline pulmonary function parameters. Conclusion: Indoor mold concentrations are a risk factor for increased bronchial hyperresponsiveness among asthmatic children with mold sensitization. Targeted environmental intervention should be considered for selected asthmatic children with mold sensitization for avoiding severe airway hyperresponsiveness.