Impedance Oscillometry: Emerging Role in the Management of Chronic Respiratory Disease

Chronic respiratory diseases affecting adults and children are widely prevalent, so lung function testing is imperative for diagnosis and management. Spirometry is the traditional standard measure of lung function; however, certain groups of patients are unable to provide accurate and reproducible exhalation maneuvers. Consequently, the impedance oscillometry system (IOS) has been developed as an effort, independent technique to assess airway function in children and the elderly. To better understand this emerging modality, the following review will compare IOS with spirometry, examine the function of the device, provide interpretation strategies, and discuss the evidence supporting its use in adults and children with chronic lung disease.

In a population of symptomatic adults with suspected COPD, impedance oscillometry resistance measurements correlate with FEV₁ and lung resistance increases with the severity of airflow limitation. In patients with asthma, IOS is a sensitive measure of airway hyperresponsiveness and bronchodilator response. Impedance oscillometry is evolving as an alternative measure to assess lung function pediatric and adult populations.