A valve assembly (50) comprising a three way connector (51) operatively interconnecting: an inlet (58) an outlet (56) and a vent (66) the inlet (58) being operatively connectable in use to an aspirator tube； the outlet (56) being operatively connectable in use to a syringe (82)； and the vent (66)comprising a one way valve (70) permitting in use the flow of a fluid out of the three way connector (51) wherein the inlet (58) comprises a receptacle (60) containing a porous or perforated element (62) which when dry permits the flow of gasses into the three way connector (51) but which when wetted by a liquid inhibits or prevents the flow of liquid into the three way connector (51).
