Alveolar Nitric Oxide and Peripheral Oxygen Saturation in Frequent Exacerbators with Asthma: A Pilot Study

<b><i>Introduction</i></b>: Asthmatics can experience recurrent exacerbations (AEs), irrespectively of asthma severity. Airway inflammatory monitoring could be fundamental to optimize the asthma management. The present study evaluated whether exhaled NO concentrations in proximal and distal respiratory compartments are different in AE-prone patients in combination with T2 blood biomarkers and resting oxygen saturation (SpO₂). <b><i>Methods</i></b>: In this observational cross-sectional study, 91 mild-to-severe asthmatics were enrolled. Clinical characteristics, blood and lung function parameters including SpO₂, and F_ENO were evaluated. On 50 randomly selected patients, C_ANO and J_awNO were also analyzed. Then, patients were stratified in frequent exacerbators (FEs) or non-frequent exacerbators (nFEs), according to AE frequency in the previous year (phase I). Chart data were re-evaluated through a 12-month follow-up period post exhaled NO measurement to detect occurrence of novel AE (phase II). <b><i>Results</i></b>: FE asthmatics had poorer asthma control and required higher therapeutic intensity (<i>p</i> &#x3c; 0.05). F_ENO, C_ANO, and J_awNO were similar between FE and nFE. FE exhibited higher total serum IgE levels and residual volume values but reduced SpO₂ than nFE (<i>p</i> &#x3c; 0.05); SpO₂&#x3c;96.5% characterized the FE patient (odds ratio = 2.94). In phase II, C_ANO was higher in the group with novel AE at 1-month post-NO measurement (<i>p</i> &#x3c; 0.05), but not afterward. A higher prevalence of C_ANO &#x3e;6 ppb was detected in asthmatics who developed AE within 1 month, suggesting its potential clinical use as biomarker in predicting near-future AE (RR = 11.20). <b><i>Conclusion</i></b>: AE-susceptible asthmatics are characterized by air trapping and distal airway inflammation in conjunction with lower oxygen saturation. C_ANO and SpO₂ could exert specific roles, respectively, in predicting AE and monitoring FE asthmatics.

Measurement of Exhaled Nitric Oxide in 456 Lung Cancer Patients Using a Ringdown FENO Analyzer

The objective of this study was to investigate the clinical value of exhaled nitric oxide (NO) for diagnosing lung cancer patients by using a relatively large sample. An online and near-real-time ringdown exhaled NO analyzer calibrated by an electrochemical sensor at clinical was used for breath analysis. A total of 740 breath samples from 284 healthy control subjects (H) and 456 lung cancer patients (LC) were collected. The recorded data included exhaled NO, medications taken within the last half month, demographics, fasting status and smoking status. The LC had a significantly higher level of exhaled NO than the H (H: 21.0 ± 12.1 ppb vs. LC: 34.1 ± 17.2 ppb). The area under the receiver operating characteristic curve for exhaled NO predicting LC and H was 0.728 (sensitivity was 0.798; specificity was 0.55). There was no significant difference in exhaled NO level between groups divided by different types of LC, tumor node metastasis (TNM) stage, sex, smoking status, age, body mass index (BMI) or fasting status. Exhaled NO level alone is not a useful clinical tool for identifying lung cancer, but it should be considered when developing a diagnosis model of lung cancer by using breath analysis.

Investigation of Primary Ciliary Dyskinesia in Children with Bronchiectasis in Iran

Background: Primary ciliary dyskinesia (PCD) is a rare genetic disorder with signs and symptoms of recurrent chronic sinusitis, otitis media, pneumonia, bronchiectasis, male infertility, and situs inversus. The diagnosis of PCD has always been one of the more challenging issues that is mostly made through screening tests. These include the saccharin test and measurements of exhaled and nasal nitric oxide (NO) level, transmission electron microscopy (TEM) for evaluating ultrastructure of the cilia, high-speed video microscopy for evaluating ciliary beat patterns, immunofluorescent staining of the cilia in the biopsies, and genetic studies. As there had not been any epidemiological studies in Iran to detect the prevalence of PCD in the general population, the current research has been undertaken for the first time using screening tests of saccharin and measurement of the level of exhaled NO (fractional exhaled NO) to investigate the prevalence of PCD. Objectives: Primary ciliary dyskinesia (PCD) is a rare genetic disorder with the basis of an abnormal ciliary movement that causes chronic respiratory infections, bronchiectasis, infertility in males, and situs inversus. The significance of earlier diagnosis is for better care and prevention of complications. In this regard, we studied the PCD in children with bronchiectasis by saccharin test and measurement of exhaled nitric oxide. Methods: In this cross-sectional study, 31 patients with a definite diagnosis of bronchiectasis were evaluated regarding nitric oxide exhalatory measurement (FeNO) and a saccharin test for the confirmation of PCD diagnosis. The cut-off point of 20 ppb was considered as the normal level for FeNO test and the sensation of fewer than 60 minutes for the normal range of the saccharin test. Age, gender, and cardioposition were recorded for the patients. Results: Unlike the saccharine test, the measurement of exhaled nitric oxide had a high sensitivity (90.3% versus 54.8%) for the diagnosis of PCD. Cardioposition and gender did not have significant effects on the outcomes of exhaled NO and saccharin test (P-value > 0.05). Besides, the patients’ age did not affect FeNO measurement but was significantly higher among those with abnormal saccharin test (P-value = 0.028). Conclusions: The FeNO test had a remarkable sensitivity of 90.3% for the diagnosis of PCD, and its outcomes were not affected by age, gender, and cardioposition. The saccharin test had a sensitivity of 54.8% and was influenced by age, while not by gender or cardioposition. Although there are more accurate tests for diagnosis of PCD such as TEM and genetic studies, we decided to investigate PCD in children with bronchiectasis by performing two screening tests, NO and saccharin, because of several issues.

Study of the role of exhaled nitric oxide (NO) in predicting controlled or uncontrolled asthma in asthmatic children

Background: Exhaled nitric oxide (NO), especially fractional concentration of exhaled NO (FENO) has been used to predict the responsiveness of inhaled corticosteroid (ICS) in children with asthma. However, the use of exhaled NO for predicting asthma control in children is still controversial.Methods: This was a randomized and cross-sectional study. Asthmatic children who were naïve to inhaled corticosteroid (ICS) were included in the present study. The measurements of FENO and CANO (concentration of NO in the gas phase of the alveolar), spirometry, blood eosinophil counts (BEC), and total IgE levels were done for each asthmatic child.Results: Ninety three asthmatic children (9±3 years) with moderate (63.4%) to severe (36.6%) asthma were included and finished the 3 month study. The levels of FENO and CANO at inclusion were 37±11 ppb and 5.8±1.4 ppb, respectively; the mean of BEC was 617±258 cells/µL; the level of total IgE was 1563±576 UI/mL; 89% of subjects were positive for at least one respiratory allergen. The percentage of severe asthma was reduced significantly after 3 months (P<0.001). Well controlled asthma subjects at 3 months had higher levels of FENO and lower levels of CANO at inclusion (P<0.05 and P<0.05). FENO <20 ppb or CANO >5 ppb had a risk of uncontrolled asthma at 3 months (OR: 1.7, CI 95% [(0.8) – (3.3)], P<0.05; OR: 1.9, CI 95% [(0.9) – (2.7)], p<0.05; respectively). FENO >35 ppb at inclusion had a positive predictive value for asthma control at 3 months (OR: 3.5, CI 95% [2.2 – 5.9], P<0.01).Conclusions: Exhaled NO is a biomarker of asthma which may have a potential role to predict the control of asthma in short-term follow-up in asthmatic children.