A plurality of tubes is combined to form a tube assembly, which may be used as an airway dilation shaft. The tubes define lumens that extend along parallel axes that are laterally offset from each other. The tubes may be contained within an outer tube or within a shrink wrap. Different functions may be achieved by the different lumens, such as inflating an airway dilation balloon, carrying oxygen or suction, delivering drugs or other substances, and carrying a guide wire. The hardness, inner diameter, outer diameter, and/or wall thickness of each tube may vary along its length. The tubes may distally terminate at different longitudinal positions. A first tube may be disposed within a second tube, with a third tube being external to yet parallel with the first and second tubes. The tubes may be tested for integrity before or after they are combined to form a tube assembly.
