Body Composition Monitoring for Determination of the Fluid Status in Volunteers Undergoing Intravenous Fluid Therapy

This volunteer study tests a recently developed whole-body bioimpedance spectroscopy device called Body Composition Monitor (BCM) which measures the body composition (i.e. the water content of the body). Specifically, the investigators will evaluate the use of BCM for correct detection of intravenous administered crystalloids in the volunteers´ fluid compartments. Furthermore we will test the change over time of the volunteers´ volume status after an intravenous fluid therapy.