Apparatus for transporting particles through a patient's trachea into the respiratory system include a delivery tube having at least a ventilation lumen and a particle delivery lumen. The delivery tube has a centering device near its distal tip, such as a balloon eccentrically mounted on the tube to position an outlet of the particle delivery lumen near a centerline of the trachea above the carina branching into the right and left bronchus. A proximal end of the delivery tube connects to a source of particles, and a controller may be provided to adjust a rate and/or an amount of the particles delivered to the patient. In a specific example, frozen particles are delivered to control core body temperature. In other instances, the particle may be a medicament or other substance for effecting other therapies or diagnostic procedures.