Bladder instillation involves introducing a therapeutic liquid (e.g. a therapeutic treatment agent) into the bladder and leaving it there for a variable ‘holding time’ to dissolve particulates or encrustations, alter pH or suppress bacterial growth.
Bladder washout involves introducing a sterile fluid into the bladder, then allowing it to drain almost immediately, in order to dilute the bladder contents or remove an obstruction and restore free catheter drainage.