This video illustrates an Infant Air-Jet DPI with a variable aerosolization chamber for the rapid administration of high-dose dry powder aerosol to infants. A 30 mg dose of synthetic lung surfactant (SLS-) excipient enhanced growth (EEG) powder formulation is initially loaded into the aerosolization chamber. Total device preparation time is ~20 sec. The device is then actuated to form an aerosol with 10 mL boluses of air. Rotation of the lower unit through levels 1-4 raises the floor of of the aerosolization chamber and presents a new consistent dose for aerosol formation during the next actuation. Using this process, the 30 mg loaded dose can be fully delivered in 4 actuations with a highly consistent mass per actuation and a highly uniform small-particle aerosol size in the range of 1.4-1.5 micrometers (volumetric median diameter) across all actuations. Total delivery time for the 30 mg dose is 20 sec.