Application of Impulse Oscillometry Combined with Fractional Exhaled Nitric Oxide in Monitoring Asthma Control Levels in Children.

PURPOSE

To investigate whether Impulse Oscillometry (IOS) could more effectively monitor children with uncontrolled asthma and evaluate small airway function changes, while establishing a prediction model in combination with fractional exhaled nitric oxide (FeNO) to assist in clinical management and treatment of asthmatic children.

PATIENTS AND METHODS

A retrospective study was conducted on 203 asthmatic children who were followed up in our hospital from August 2023 to August 2024. Patients were divided into controlled asthma group (n=80) and uncontrolled asthma group (n=123). Conventional ventilatory parameters, IOS parameters, FeNO levels, and clinical data were analyzed and compared between the two groups. The optimal prediction model was established through multivariate logistic regression.

RESULTS

In the uncontrolled asthma group, the respiratory system impedance at 5 hz (Z5), resistance at 5 hz (R5), the difference between resistance at 5 hz and resistance at 20 hz (R5-R20), resonant frequency (Fres), and FeNO levels were significantly higher compared to the controlled asthma group. The ratio of forced expiratory volume in one second to forced vital capacity (FEV/FVC), forced expiratory flow at 50% (FEF50), forced expiratory flow at 75% (FEF75), and maximal mid-expiratory flow (MMEF) were lower in the uncontrolled group (P<0.05). Receiver operating characteristic curve (ROC) analysis demonstrated that Z5, R5, R5-R20, Fres, and FeNO were valuable in asthma diagnosis (P<0.05), with higher sensitivity in monitoring small airway function compared to MMEF. Multivariate logistic regression analysis established the optimal prediction model combining R5+(R5-R20) +FeNO, with an area under curve (AUC) of 0.915 (P<0.05), sensitivity of 0.831, and specificity of 0. 892.

CONCLUSION

Compared to conventional pulmonary function tests, IOS effectively identifies uncontrolled status in asthmatic children, particularly in younger patients, with higher sensitivity to small airway function changes. The model comprising R5+(R5-R20) +FeNO demonstrates clinical value in identifying uncontrolled status in asthmatic children.