A pump assembly 12 for use as part of a pumped aspirator 10, the pump assembly 12 comprising a vacuum pump 38 and a chamber 30, the chamber 30 comprising an inlet 26 connectable to an aspirator tube 14 and an outlet 34 connectable to the pump 38. The chamber 30 further comprises a hollow interior volume containing a porous or perforated element 32 separating the inlet 26 from the outlet 34 the porous or perforated element 32, when dry, permitting the passage of gas from the inlet 26 to the outlet 34, but when wetted by a liquid, inhibiting the passage of fluids from the inlet 26 to the outlet 34. The pump 38 is further preferably driven by a motor 40 connected to a power supply 44 via a switch gear of a control circuit 42, and wherein the switch gear is adapted to switch off the motor 38 when the air pressure downstream of the outlet 34 drops below a threshold value indicative of the porous or perforated element 32 inhibiting the passage of fluids from the inlet 25 to the outlet 34.
