A connection adapter for producing a detachable fluid connection between a first fluid system and a second fluid system is provided, the connection adapter comprising a switching valve; a housing including a pressure chamber and a valve chamber fluidly connected; an actuation element to actuate the switching valve to selectively open and close the fluidic connection; a ventilation path leading out of the connection adapter from the valve chamber; a ventilation shut-off means to close and open the ventilation path; a connection element fluidly connecting the pressure chamber to the first fluid system; a quick fastener socket fluidly connecting to the valve chamber and connects the valve chamber to a connection element of the second flush system; and a locking mechanism to lock the quick fastener socket and is restricted to a locked position when the ventilation shut-off means closes off the ventilation path.