Preschool Lung Functıon Testıng and the Upper Respıratory Tract

Respiratory tract diseases occur due to improper and incompliant functioning of upper and lower airways according to united airway theory. Respiratory function tests have an important place in the diagnosis, treatment, and follow-up of these conditions. The selection of the treatment method appropriate for the age group, taking anatomical, physiological, and psychosocial parameters into consideration, provides beneficial outcomes. In this review, we will emphasize the changes in the upper airways based on age in preschool children and their consequences, and will explain the various techniques used to evaluate the respiratory function and their applicability.