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

Piyawut Kreetapirom; Potjanee Kiewngam; Wanlapa Jotikasthira; Wasu Kamchaisatian; Suwat Benjaponpitak; Wiparat Manuyakorn

doi:10.5415/apallergy.2020.10.e3

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

Asia Pac Allergy. 2020 Jan 17;10(1):e3. doi: 10.5415/apallergy.2020.10.e3. eCollection 2020 Jan.

Authors

Piyawut Kreetapirom¹, Potjanee Kiewngam¹, Wanlapa Jotikasthira¹, Wasu Kamchaisatian¹, Suwat Benjaponpitak¹, Wiparat Manuyakorn¹

Affiliation

¹ Division of Allergy and Immunology, Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.

Abstract

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 FEF_25%-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.

Keywords: Asthma; Frequency of resonance; Reactance; Resistance; Spirometry.