Central Venous Pressure (CVP) is non-invasively determined with accuracy comparable to invasive measurement techniques. To do so, curves are plotted based on non-invasively determined patient information obtained by applying a controllable variable (pressure) to a vein of interest at a non-distal point and taking certain measurements (such as pressure and volume measurements) from the patient. An example of a controllable variable is voltage applied in incremental inflation/deflation of a vascular cuff (1). A curve is plotted based on datapoints (such as a volume increase curve or a volume decline curve). Pertinent, accurate CVP and/or blood volume information is obtained from the slope of the non-invasive-based curve. Accurate CVP information is provided without the risks and disadvantages of invasive measurements.