The use of exhaled nitric oxide and peak expiratory flow to demonstrate improved breathability and antimicrobial properties of novel face mask made with sustainable filter paper and Folium Plectranthii amboinicii oil: additional option for mask shortage during COVID-19 pandemic

Background

Medical face masks are integral personal protective equipment against infectious airborne disease and become scarce during epidemic outbreaks such as COVID-19. A novel, sustainably manufactured face mask with antimicrobial and anti-inflammatory properties from oil of Folium Plectranthii amboinicii can be an effective alternative to internationally sold masks.

Methods

This prospective, randomized study assigned subjects (n=67) to either conventional surgical face mask or Lamdong Medical College (LMC) face mask for three hours. Fractional concentration of nitric oxide in exhaled breath (FE_NO) and peak expiratory flow (PEF) was measured before and after mask use. Subjective reporting on respiratory symptoms was also analyzed. Masks were then incubated and analyzed for microorganism growth.

Results

Subjects assigned the LMC mask had a lowered FE_NO (p<0.05) compared to conventional face masks after mask wearing. Subjects with LMC mask use reported higher comfortability (p<0.05), breathability (p<0.05), and lower allergy symptoms (p<0.05). The LMC mask has visually less microorganism growth in the cultured medium, measured by sterile ring radius.

Conclusions

The LMC face mask is a renewably manufactured personal protective tool with antibacterial capacity that can serve as an effective alternative to internationally sold surgical face mask during shortage of mask due to COVID-19.

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 (FE_NO) has been used to predict the responsiveness to 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 perspective observational study. Asthmatic children who were naïve to inhaled corticosteroid (ICS) were included in the present study. The measurements of FE_NO and CA_NO (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. All study subjects started proper asthma treatment after the enrollment.

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 FE_NO and CA_NO 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 FE_NO and lower levels of CA_NO at inclusion (P<0.05 and P<0.05). FE_NO<20 ppb or CA_NO>5ppb 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). FE_NO>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.

Study of nasal exhaled nitric oxide levels in diagnosis of allergic rhinitis in subjects with and without asthma

Background

The measure of fractional exhaled nitric oxide (FENO) in the airways is a useful tool to guide the diagnosis and titration of inhaled corticosteroids in patients with asthma. However, its role in diagnosis of allergic rhinitis (AR), especially in subjects with asthma, is not well established.

Objective

To study the cutoff of nasal FENO in the diagnosis of subjects with AR and AR-asthma compared to age-matched subjects without AR or asthma and its correlations with the clinical and functional characteristics.

Methods

The study was cross sectional and descriptive. Subjects were grouped into control subjects, AR, and AR-asthma, based on the inclusion criteria. Exhaled NO (nasal FENO, bronchial FENO, and alveolar concentration of NO) was measured by multiple flow electro-luminescence device.

Results

Six hundred twenty-eight subjects were included: 217 control subjects (children: n=98, 10±4 years; adults: n=119, 50±16 years), 168 subjects with AR (children: n=54, 10±3 years; adults: n=114, 49±15 years), and 243 subjects with AR-asthma (children: n=115, 10±3 years; adults: n=128, 51±14 years). Nasal peak inspiratory flow and peak expiratory flow were lower in subjects with AR and AR-asthma than in control subjects (P<0.01 and P<0.01; and P<0.05 and P<0.01, respectively). Nasal FENO levels were significantly higher in subjects with AR and AR-asthma than in control subjects (1614±629 and 1686±614 ppb vs 582±161 ppb; P<0.001 and P<0.001, respectively). In subjects with AR non-asthma, the cutoffs of nasal FENO for those diagnosed with AR were 775 ppb in children, 799 ppb in adults, and 799 in the general population (sensitivity: 92.68%, 92.63%, and 92.65%, respectively; specificity: 91.67%, 95.00%, and 96.87%, respectively). In subjects with AR-asthma, the cutoffs of nasal FENO were higher, especially in asthma children (1458 ppb; sensitivity: 72.97% and specificity: 95.83%).

Conclusion

Nasal FENO measurement is a useful technique for the diagnosis of AR in subjects with and without asthma.

[Early detection of smoking related chronic obstructive pulmonary disease in Vietnam]

INTRODUCTION

Epidemiological studies of chronic obstructive pulmonary disease (COPD) are rare in the developing countries, particularly in Viet Nam where the consumption of tobacco continues to increase. The aim of this study was to evaluate the feasibility of early screening of smokers for bronchial obstruction using the Piko-6 apparatus.

MATERIALS AND METHODS

Smokers over 40 years of age who had smoked for more than 10 years were included. The subjects were classified into 3 groups according to the degree of bronchial obstruction measured by the Piko-6. (group 1: FEV1/FEV6>0.8; group 2: 0.7-0.8; group 3:<0.7). The smokers in group 3 and a sample of the smokers in groups 1 and 2 were recalled for full spirometric assessment.

RESULTS

2397 smokers were included, comprising 2130 active smokers and 267 ex-smokers. The mean age was 52 +/- 13 years. The mean smoking history was 24 +/- 13 pack years. 267 smokers from the 3 groups responded to the recall for full investigation. The prevalence of COPD detected by the Piko-6 in the study population was 13.5%. For the threshold FEV1/FEV6<0.7 and with the detected prevalence, the Piko-6 had a sensitivity of 97.8%, a specificity of 93.8%, a positive predictive value of 71% and a negative predictive value of 99.6% (confidence interval 95%).

CONCLUSIONS

The Piko-6 is a useful tool for the early screening for COPD in smokers in a developing country where the prevalence of this disease appears to be under estimated.