ABSTRACT
Sensitive measures of lung function are important for the assessment of chronic diseases such as cystic brosis (CF). In CF, lung disease is known to be present in early childhood, and, if le untreated, leads to a progressive spiral of infection and inammation, resulting in lung damage and ultimately pulmonary insuciency. Spirometry derived parameters, such as the forced expiratory volume in 1 second (FEV1), are used extensively in the assessment and follow-up of CF patients. Not only are they used to classify severity of disease but also to predict outcomes as FEV1 has been linked to mortality. However, it is common for children with CF to maintain FEV1 within the normal range well into the second decade of their lives.1 is is despite evidence of progression of lung disease when assessed by other techniques such as high-resolution computed tomography (CT) scans.2,3 With the advent of newborn screening and the recognition that CF lung disease begins in early life, there has been increased attention on developing noninvasive methods to detect these early abnormalities. ese new objective assessment methods are critical to perform interventional trials in early childhood. Sensitive noninvasive tests of lung function replacing spirometry are, therefore, needed both for the clinical setting and research studies.
