In sharp contrast, other studies (Charra, Özkahya)(3,4) have shown that a strict volume control strategy decreases blood pressure (BP) without drugs, and prolongs survival. This suggests that volume control is insufficient in most dialysis centers, despite the fact that treating physicians may consider that ''Dry Weight'' (DW) of their patients has been reached. In fact, there is no easily applicable method to determine extra cellular volume and consequently estimate DW. Thus DW has to be clinically defined by ''trial and error'' and several indirect methods.