A medical device comprises a fluid cartridge (810) comprising a chamber (811, 812) and a piston (813). The medical device further comprises an impeller located within the chamber (811, 812) and a static mixer in fluid communication with the chamber (811, 812). A lockout mechanism is reversibly coupled to the fluid cartridge (810), wherein (a) the lockout mechanism is movable between a first configuration which prevents the movement of the piston (813) and a second configuration which permits the movement of the piston (813) and (b) the lockout mechanism moves from the first configuration to the second configuration after the impeller has undergone a predetermined number of rotations within the chamber (811, 812).
