Nasopharyngeal isolates and their clinical impact on young children with asthma: a pilot study.

INTRODUCTION: Respiratory infections have significant effects on childhood asthma. Viral respiratory infections, such as rhinovirus and respiratory syncytial virus are likely to be important in the development and exacerbation of asthma. In this study, we investigated the nasopharyngeal colonization in children with asthma to determine the prevalence of pathogens and their contribution to respiratory symptoms and airway resistance during winter. METHODS: From December 2016 to March 2017, 50 nasopharyngeal specimens were collected from 18 patients (age, 5.0±1.1 years) with asthma and 9 specimens from 9 control children (age, 4.9±1.0 years). Samples were tested for 19 viruses and 7 bacteria, using multiplex real-time PCR. Respiratory disease markers included the Global Asthma Network Questionnaire, the Common-Cold Questionnaire, the Global Initiative for Asthma assessment of asthma control, and the airway resistance at 5 Hz by forced-oscillation technique. RESULTS: The most commonly isolated organisms in both groups (patients and controls) were Streptococcus pneumoniae, Haemophilus influenzae, and rhinovirus. Most patients had multiple isolates (median, 3.5; range, 1-5), which changed during the study period. Types of isolates were 4 bacteria (S. pneumoniae, H. influenzae, Bordetella pertussis, and Bordetella parapertussis) and 6 viruses (rhinovirus, enterovirus, metapneumovirus, adenovirus, coronaviruses, and parainfluenza viruses). Similar isolates, including influenza A-H3 virus and bocavirus, were detected in the controls. Of the 9 patients with "wheezing disturbing sleep ≥1 per week", 6 had rhinovirus, 2 coronaviruses, and 1 no detectable viruses. Patients with mild common cold symptoms had significantly higher airway resistance at 5 Hz z-score (P=0.025). CONCLUSION: Multiple respiratory pathogens were isolated from many patients with asthma, which appeared to contribute to disease symptoms and airway resistance. Minimizing children's exposure to respiratory pathogens might be beneficial, especially during winter.

Respiratory function in healthy Emirati children using forced oscillations.

BACKGROUND: The forced oscillation technique (FOT) allows the quantification of respiratory function, does not require active cooperation and as such is ideally suited for use in young children. The application of the FOT in non-Caucasian populations is limited and it remains unclear if current reference ranges for the FOT in Caucasian children are appropriate for children in the Arabian Peninsula. This study explored the use of the FOT in healthy school-aged children in the United Arab Emirates (UAE). METHODS: Lung function using FOT was assessed in healthy Emirati children aged 4-12 years. Using a validated questionnaires general medical and respiratory histories were obtained. Prediction equations for resistance (Rrs), reactance (Xrs), and area under reactance curve (AX) were calculated and compared to previous studies. RESULTS: FOT was successfully obtained in 291 healthy Emirati children. Linear regression modelling including weight, height, age, and gender in transformed FOT outcomes demonstrated that height was the strongest predictor of FOT outcomes (P < 0.001). Using the equated prediction equation Z-scores were calculated. FOT outcomes in Emirati children did not match previously published reference equations in Caucasians children (P < 0.001). CONCLUSION: FOT measurements were feasible in Emirati school-children. New FOT reference equation in Emirati children were derived. FOT reference equation in Emirati children was different from published equations in Caucasians.

Is forced oscillation technique the next respiratory function test of choice in childhood asthma.

Respiratory diseases, especially asthma, are common in children. While spirometry contributes to asthma diagnosis and management in older children, it has a limited role in younger children whom are often unable to perform forced expiratory manoeuvre. The development of novel diagnostic methods which require minimal effort, such as forced oscillation technique (FOT) is, therefore, a welcome and promising addition. FOT involves applying external, small amplitude oscillations to the respiratory system during tidal breathing. Therefore, it requires minimal effort and cooperation. The FOT has the potential to facilitate asthma diagnosis and management in pre-school children by faciliting the objective measurement of baseline lung function and airway reactivity in children unable to successfully perform spirometry. Traditionally the use of FOT was limited to specialised centres. However, the availability of commercial equipment resulted in its use both in research and in clinical practice. In this article, we review the available literature on the use of FOT in childhood asthma. The technical aspects of FOT are described followed by a discussion of its practical aspects in the clinical field including the measurement of baseline lung function and associated reference ranges, bronchodilator responsiveness and bronchial hyper-responsiveness. We also highlight the difficulties and limitations that might be encountered and future research directions.