Profiled dialysis is a new conceptual approach to patient intradialytic vascular instability. It is based on the continuous modulation of dialysis operative parameters, such as dialysate sodium and UF rate, according to pre-established profiles. The points to be defined for profiled dialysis are: (a) the patient's individual sodium and masses already stated; (b) the patient's individual algorithms to fit the clinically effective intradialytic variations in plasma sodium and sodium mass; (c) a mathematical model from which sodium and UF profiles are automatically worked out at the beginning of each session. The basic concept of profiled dialysis should evolve towards an ongoing "profiling' programme. This is based on the continuous on-line intradialytic adjustment of profiles according to the patient's emerging clinical requirements.