Spirometry relates poorly to symptoms, new lung function tests may help dismantle disease mechanisms

5 April, 2019

In a new article published in the European Respiratory Review, Sabine Zimmermann, Katrina Tonga and Cindy Thamrin describe two emerging lung function tests that have the capability to yield novel pulmonary function indices, including the forced oscillation technique (FOT) and the multiple breath nitrogen washout (MBNW) test, focusing on their use in asthma and COPD assessment.

The authors describe the ability of FOT and MBNW to assess detailed pulmonary mechanics for diagnostic and management purposes, including response to bronchodilation and other treatments, relationship with symptoms, evaluation of acute exacerbations and recovery, and telemonitoring.

The review notes that spirometry remains the gold standard test of lung function, particularly in asthma and COPD, but highlight how this method has several shortcomings, including that it relates poorly to symptoms and lacks sensitivity in detecting early disease. Further, the authors criticise spirometry for being effort-dependent because it requires forced expiratory manoeuvres that can be very difficult for some patients to perform.

In outlining the capabilities of FOT, the review covers aspects including: detection of expiratory flow limitation; relationship with symptoms, disease status and severity; evaluation of bronchodilator/treatment response; changes during recovery from exacerbation; home telemonitoring of chronic airway disease; and disease phenotyping and classification.

Further, the review also discusses the MBNW test, assessing how it performs regarding: relationship with symptoms and disease status; relationship with airway hyperresponsiveness; and evaluation of bronchodilator/treatment response.

The authors also outline current limitations of both tests and discuss open questions and directions for further research.