Forced Oscillation and Breathing Pattern in Asthma

Plain-language summary

Asthma is a chronic respiratory disease characterised by airway inflammation, bronchoconstriction, and airway hyperresponsiveness. Accurate and reliable assessment of lung function is crucial in diagnosing and monitoring asthma. The forced oscillation technique (FOT) is a non-invasive method that has gained attention in recent years as a valuable tool for evaluating respiratory mechanics in asthma. FOT involves applying small amplitude oscillations at various frequencies to the respiratory system and measuring the resulting pressure and flow responses. These measurements provide valuable insights into the mechanical properties of the airways, including resistance, compliance, and reactance. FOT offers several advantages over traditional spirometry, such as its ability to assess peripheral airway function, sensitivity to small airway abnormalities, and ease of use, particularly in young children or individuals with severe airflow limitation. FOT also allows for assessment of respiratory mechanics in individuals who may struggle with performing spirometry manoeuvres. However, it is unclear whether a change in breathing pattern in patients with obstructive lung disease impacts the assessment of a response to treatment utilising FOT. Several studies have demonstrated a high prevalence of Breathing Pattern Disorders (BPDs) in individuals with asthma. These findings suggest that BPDs may be common in asthma and could contribute to the manifestation and severity of respiratory symptoms. Evidence suggests that BPDs can adversely affect pulmonary function in individuals with asthma. One study demonstrated that children with asthma and dysfunctional breathing exhibited significantly reduced forced expiratory volume in one second (FEV1) compared to asthmatics without BPD. This suggests that abnormal breathing patterns may contribute to airflow limitation in asthma, leading to decreased lung function. We therefore wish to determine the impact of different breathing frequencies on parameters measured using FOT in patients diagnosed with asthma and concomitant obstructive lung function abnormality.

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