Ventilation apparatus includes a hat having an axis of symmetry and composed of a top and sides extending down to a rim extending all around the hat. An elongated flexible panel encircles the rim. Securements secure the panel to the rim at spaced-apart locations therearound to provide a plurality of relatively long channels extending between the rim and the panel. Each channel extends parallel to the axis and is sized to slidably receive a tube. In use, a patient wears the hat and inlet and outlet tubes are retained in selected hat channels so as to stabilize a patient interface cannula connected to the tubes so that the cannula's nasal prongs remain properly positioned in the patient's nares.