Momentary high pressure valve

A valve (10) comprises a housing (12) with a valve element (14) which normally fluidicly couples a low pressure operating device, such as a transducer (30) and tubing (34) to be coupled to a patient (36) along a first flow path (42) including a flexible control wall (58) which normallyinterrupts a second flow path between a high pressure generating source such as an injector syringe (32) and the tubing (34), (72) but which flexes, in response to high pressure excursions from the syringe (32) to allow the second flow path (72) to open as it flexes into the first flow path (42) to thereby restrict same thus providing protection to the transducer (30) during the high pressure excursion from the syringe (32).