A coupling for connecting a ventilator tube to an improved single cannula tracheotomy tube has a latching mechanism which prevents the coupling from inadvertently axially displacing from a tapered tubular extension of the tracheotomy tube after they have been mated in a pneumatically discrete path. Non-axial and non-rotational forces are used to engage and disengage the coupling from the tracheotomy tube. The coupling has a trailing end adapter which permits rotation of the coupling relative to the ventilator tube rather than to the tracheotomy tube.