A device for dilating an Eustachian tube of a patient including an inner member, an inflation fluid supply tube, a balloon, and a coupler. The inner member includes a lumen fluidly open at distal and proximal ends. The inner member has a distal portion, a proximal portion, and a central portion. The inflation fluid supply tube is fixedly disposed around the central. The inflation fluid supply tube has an opening disposed between first and second ends. A proximal portion of the inner member extends through the opening and the opening is fluidly sealed against an exterior surface of the inner member. The coupler is configured to selectively couple the inflation fluid supply tube to an endoscope. The coupler is configured to engage against an exterior surface of the inflation fluid supply tube. The coupler is disposable between the first end and the opening of the inflation fluid supply tube.
