Speaking valves, tracheostomy tubes and assemblies

摘要

A fenestrated tracheostomy tube (1) intended for use with a speaking valve (3) has a machine end coupling (15) of circular section with two opposite flat surfaces (51). The speaking valve (3) is similarly formed with a mating inner surface (35) having matching flat surfaces (36) that prevent the valve being fitted on conventional couplings with an entirely circular section. A fenestrated inner cannula (40) can be fitted in the tracheostomy tube (1), the inner cannula having a flange (45) at its machine end with flat regions (46) that align with the flat surfaces (51) on the coupling (15) so that the speaking valve (3) can be fitted over the flange. The speaking valve (3) also has an inner ring (38) that is a close sliding fit within the hub (44) of the inner cannula (40) and prevents the valve being fitted with conventional inner cannulae having a hub with a smaller internal diameter.