A system and method of monitoring the fluid status of a patient. The system may include a patient monitor that receives blood pressure data. A first fluid model receives the blood pressure data, and a personalized fluid model is derived from the application of the blood pressure data to the first fluid model. An estimation of the patient's fluid status may be derived from the personalized fluid model. The method may include the steps of measuring a first blood pressure value, creating a personalized fluid model, measuring a second blood pressure value, applying the second blood pressure value to the personalized fluid model; and deriving an estimation of the fluid status of the patient.