Figure 2.

Demonstration of lung function measurements using FOT. On the left, a photograph of the FOT test being performed in a 5-year-old boy. The hands of the investigator support the cheeks and the floor of the mouth of the child. The nose is blocked using a nose clip. The lips are sealed around the mouthpiece. On the right, Different breathing patterns during FOT measurements are shown, as observed on the flow-time trace in L/s. A: Normal tidal breathing; B: Breath holding spells; C: An aberrant activity (e.g., coughing, swallowing, or noise); D: A leak around the mouthpiece. FOT: Forced oscillation technique.