Method and device for determining volemic status and vascular tone

A method for determining a volemic status and a vascular tone of the hemodynamic system, wherein the method comprises:

• (i) sensory detection of a photoplethysmography (PPG) signal from a living tissue, the PPG signal having an alternating current (AC) component as a PPG amplitude and a direct current (DC) component as a PPG baseline,
• (ii) determining a multiplicity of PPG signals from the living tissue;
• (iii) determining a multiplicity of AC components of the PPG signals,
• (iv) determining a multiplicity of DC components of the PPG signals,
• (v) determining a multiplicity of AC waveforms from the AC components, and
• (vi) identifying differences in the AC waveforms over time by comparing at least two of the AC waveforms,
• (vii) determining a DC signal trend over time by comparing at least two of the DC components;
• and
• (viii) determining the vascular tone and the volemic status of the hemodynamic system of the living tissue as a reaction to at least one of the AC waveform difference and/or the DC signal trend over time, respectively,
• and wherein a computer analyzes the AC components of the multiplicity of PPG signals as a measure for the vascular tone and determines a shift of the DC components of the multiplicity of PPG signals over time as a measure for the volemic status.