А rectal drainage appliance (10) is disclosed. The appliance has а tubular element (12) defining а drain passage with an inflatable balloon (20) at а distal end for insertion into the rectum. An auxiliary lumen (24) communicates with the inflatable balloon (20) and is coupled to a pressure indicator (34) on an inflation port (26) for indicating а pressure level within the balloon (20). The pressure indicator (34) comprises а first mechanical element (36) configured to flip between first and second physical states depending on the sensed pressure.