Long-term Respiratory Complications in Infants With Perinatal COVID-19

Patients will undergo pulmonary function tests with the Exhalyzer D (Ecomedics, Switzerland) device. This device consists of 1) an ultrasonic flow measuring system for measuring flow, volume and molecular mass, 2) a nitrogen washout system to measure functional residual capacity (FRC) and other indices, 3) a carbon dioxide infrared measurement device for monitoring the level of carbon dioxide in exhaled breath.