Forced oscillation technique as a predictor for loss of control in asthmatic children

BACKGROUND: A reliable objective tool using as a predictor of asthma control status could assist asthma management.OBJECTIVE: To find the parameters of forced oscillation technique (FOT) as predictors for the future loss of asthma symptom control.METHODS: Children with well-controlled asthma symptom, aged 6–12 years, were recruited for a 12-week prospective study. FOT and spirometer measures and their bronchodilator response were evaluated at baseline. The level of asthma symptom control was evaluated according to Global Initiative for Asthma.RESULTS: Among 68 recruited children, 41 children (60.3%) maintain their asthma control between 2 visits (group C-C), and 27 children (39.7%) lost their asthma control on the follow-up visit (group C-LC). Baseline FOT parameters, including the values of respiratory resistance at 5 Hz (R5), respiratory resistance at 20 Hz (R20), respiratory reactance at 5 Hz, area of reactance, %predicted of R5 and percentage of bronchodilator response (%∆) of R5 and R20 were significantly different between C-C and C-LC groups. In contrast, only %∆ of forced vital capacity, forced expiratory volume in 1 second (FEV₁), and FEF25%–75% (forced expiratory flow 25%–75%) were significantly different between groups. Multiple logistic regression analysis revealed that %predicted of R5, %∆R5, %predicted of FEV₁ and %∆FEV₁ were the predictive factors for predicting the future loss of asthma control. The following cutoff values demonstrated the best sensitivity and specificity for predicting loss of asthma control: %predicted of R5=91.28, %∆R5=21.2, %predicted of FEV₁=89.5, and %∆FEV₁=7.8. The combination of these parameters predicted the risk of loss of asthma control with area under the curve of 0.924, accuracy of 83.8%.CONCLUSION: Resistance FOT measures have an additive role to spirometric parameter in predicting future loss of asthma control.

Efficacy of Nasal Cellulose Powder in the Symptomatic Treatment of Allergic Rhinitis: A Randomized, Double-Blind, Placebo-Controlled Trial

PURPOSE: Nasal Cellulose Powder (NCP), which can prevent from binding an allergen to nasal mucosa, may reduce allergic rhinitis (AR) symptoms in dust mite-sensitized children. This study was conducted to assess the efficacy of NCP in improving clinical symptoms of a nasal airflow limitation and the response of nasal inflammatory cells. METHODS: Children with dust mite-sensitized AR aged 6–18 years were recruited. After a 4-week run-in period, NCP or a placebo was administered, 1 puff per nostril 3 times daily for 4 weeks. The nasal provocation test (NPT) with Dermatophagoides pteronyssinus (Der p) was performed before and after treatment. The daily symptom scores (DSS), daily medication scores (DMS), the peak nasal inspiratory flows (PNIF), nasal airway resistance (NAR), as well as the maximum tolerated dose of NPT and eosinophil counts in nasal scraping, were evaluated. RESULTS: Sixty children (30 NCP and 30 placebos) were enrolled. Before treatment, there were no significant differences in age, dust mite control measures, DSS, DMS, PNIF, NAR, the maximum tolerated dose of NPT, or nasal eosinophil scores between children receiving NCP and placebos. After treatment, there were no significant differences between the NCP and placebo groups in the median (range) of the outcomes—DSS: 2.06 (0.18–3.77) vs. 1.79 (0.08–7.79), P=0.756; DMS: 1.60 (0–5.13) vs. 0.56 (0–4.84), P=0.239; PNIF (L/min): 110 (60–160) vs. 100 (50–180), P=0.870; NAR (Pa/cm³/s): 0.40 (0.20–0.97) vs. 0.39 (0.24–1.32), P=0.690; the maximum tolerated dose of NPT and the nasal eosinophil scores: 1 (0–4) vs. 1 (0–4), P=0.861. CONCLUSIONS: NCP treatment may not be more effective than placebo treatment in dust mite-sensitized AR children.

Airway remodelling in asthma: role for mechanical forces

Asthma is a chronic airway inflammatory disease with functional and structural changes, leading to bronchial hyperresponsiveness and airflow obstruction. Airway structural changes or airway remodelling consist of epithelial injury, goblet cell hyperplasia, subepithelial layer thickening, airway smooth muscle hyperplasia and angiogenesis. These changes were previously considered as a consequence of chronic airway inflammation. Even though inhaled corticosteroids can suppress airway inflammation, the natural history of asthma is still unaltered after inhaled corticosteroid treatment. As such there is increasing evidence for the role of mechanical forces within the asthmatic airway contributing to airway structural changes.