A device 9 is configured for separating fluid F recovered from a patients cavity from gas G recovered from the cavity. Preferably, the device comprises a chamber 10 with a gas inlet port 11, respective gas and fluid outlet ports 12, 13, and sloped condensation surfaces 15. The device 9 is for use with an apparatus (1, fig 2) for providing agitation inside the cavity when filled with a therapeutic fluid by circulating gas through the cavity, such as during hyperthermic intraperitoneal chemotherapy. Preferably, the separated gas G and fluid F output from the device 9 are recirculated into gas and fluid delivery systems (3,14, fig 2) of the agitation apparatus 1 respectively. The device may be secured to the patient by a hollow pin (18, fig 7B) which engages with the inlet port 11 and has a base (18A, fig 7B) for positioning under an opening in the patients skin adjacent the cavity. A bowl-shaped filter (21, fig 10) adjacent the pin base may prevent blockage of the inlet port 11.
