Abstract: A lung ventilation device has a stem to fit in a trachea, having at least two ventilation passageways communicating with distal passageways configured to fit in the bronchi at the carina. There is a positioning balloon to engage the walls at the carina when inflated. The positioning balloon has a proximal annular portion surrounding a distal end of the stem, and a plurality of annular distal portions, each surrounding a distal passageway end. The distal balloon portions are extensions of the proximal balloon portion. There may be a frangible link between the distal passageways, to break to separate the distal passageways in situ for bronchi entry as the positioning balloon is inflated. There may be stylets extending along the stem and arranged to provide stiffness to the distal passageways during device advancement in the trachea.