A pump device (10) operable with a syringe (11) having a barrel (12) and a plunger (13). The pump device (10) is operable to cause relative movement between the syringe plunger (13) and the syringe barrel (12) for discharging fluid from the syringe (11). The pump device (10) comprises a portion (31) adapted to engage the syringe barrel (12), and a drive mechanism for moving the syringe plunger (13) relative to the syringe barrel (12) to discharge fluid from the syringe (11). The drive mechanism comprises an actuator (45) adapted to engage the syringe plunger (13) and a power mechanism (61) for moving the actuator (45) to effect movement of the syringe plunger (13) relative to the syringe barrel (12). The pump device (10) thus provides a syringe driving means. There is also provided an infusion system comprising a syringe driving means, the syringe driving means comprising the pump device (10). Further, there is provided an infusion system comprising a syringe driving means operable to maintain a constant pressure within a syringe and tubing with viscosity corrections for various antibiotic concentrations.
