Lung function assessment in preschool children; a review of the utility of basic spirometry, interrupter technique and forced oscillation technique

Objective lung function assessment in preschool children is a challenge; the mechanics of the lungs are changing rapidly with advancing age and maturation, the population is too old to ethically justify routine sedation prior to lung function assessment, as in infants, and also, they are too young to be able to focus sufficiently and perform elaborate respiratory manoeuvers required by commonly used lung function tests in older children and adults. But, clinically, a clear evidence based demarcation between isolated non-significant episodes of respiratory symptoms and pathognomonic symptoms is vital for the management. Even though many different lung function techniques are commonly used in the assessment of preschool children, the purpose of this review is to evaluate three commonly used pulmonary function tests, viz. basic spirometry, interrupter technique and forced oscillation technique in order to assess their usefulness in preschool children. We conclude that contrary to common misbelief, ample evidence exists that preschool children are capable of performing lung function tests. Basic spirometry, which stood the test of time, remains one of the most commonly used lung function tests. The interrupter technique and the forced oscillation techniques are quickly gathering reputation as reliable alternatives for lung function assessment in preschool children, especially due to the minimal co-operation required from the subject and the versatility of the test. These techniques will enable definitive diagnosis, assessment of severity and the therapeutic response of multiple, complex and often challenging clinical respiratory conditions to enable efficient management