A valve (20) for the sealing cuff (10) of a tracheal tube has a valve member (40) urged against a valve seal (36, 37) by an MRI-safe resilient member (42) of neoprene or nitrile. The valve includes a two-part actuator (70) by which the valve member is displaced. Before use, during storage, the valve member is in a closed position with the resilient member relatively relaxed. When the valve is opened for the first time by inserting a syringe or the like, the two-part actuator arrangement is moved forwards to unseat the valve member to allow flow. This causes inclined surfaces (88) and (92) on the two parts (72) and (73) of the actuator to rotate the forward part slightly. When the syringe is removed to allow the valve to close, the forward part of the actuator latches on a surface (34) of the housing (21) in an operational position where the valve is closed.
