New Testing Technique for Cystic Fibrosis Shown to Effectively Evaluate Lung Function

In a recent study published in the journal BioMedical Engineering OnLine, a research team from the University of Rio de Janeiro assessed the effectiveness of Forced Oscillation Technique for the evaluation of biomechanical lung function changes in patients with Cystic Fibrosis.

With a mortality rate of 85%, pulmonary disease is a major cause of morbidity and mortality in individuals with Cystic Fibrosis (CF). As a result, there is a clinical need to further understand the overall changes in CF patients’ lung function and the mechanisms of lung injury. Increased knowledge in these areas could help guide choices in clinical care and the development of new therapies.

Forced Oscillation Technique (FOT) offers a simple and detailed approach to investigate the mechanical properties of the respiratory system and represents the current state-of-the-art assessment of lung function. This method consists of the application of sinusoidal signals during normal respiration by means of an external pressure generator, allowing for the measurement of respiratory system impedance. In addition to being useful in furthering our understanding of respiratory biomechanical function, these model parameters could improve the detection, diagnosis, and treatment of different respiratory diseases. Therefore, FOT has the potential to increase knowledge about the biomechanical abnormalities of adults with CF.

Background Terminology

• Sinusoidal signals: describes a smooth repetitive oscillation. 
• Spirometry: is the measurement of breath.
• Plethysmography indexes: is a new, totally non-invasive, easy-to use dynamic parameter that has been validated to guide fluid administration by predicting fluid responsiveness in adult patients.

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In their study entitled “Forced oscillations and respiratory system modeling in adults with cystic fibrosis,” a total of 27 adults with CF and a control group of 23 healthy individuals were examined with the FOT, plethysmography and spirometry. To gain further insight into biomechanics changes, all participants were examined with an equivalent electrical circuit mode.

When compared to the healthy controls, adult patients with CF had an increase in total respiratory resistance, an increase in the resistance curve slope and also a reduction in the dynamic compliance. The results also showed that patients with CF had an increase in peripheral resistance and a reduction in compliance. The researchers found correlations between the resistive parameters and spirometric and plethysmographic indexes. When they evaluated the reactive parameters the results were similar to associations between peripheral resistance and plethysmographic parameters.

Based on the results, the research team strongly believes that FOT is an effective tool to assess CF-related biomechanical changes. In the article, the authors further indicate that this model is accurate in providing lung function indicators, and also is able to differentiate between obstructed and non-obstructed airway conditions in patients with CF.