Besides common vital signs such as SpO2, RR and ECG, esCCO™ also offers a realtime non-invasive CO-measurement. Mainly, the esCCO™ principle is based on the possibility to obtain CO-values using pulse pressure analysis: CO = SV × HR = (C × PP) × HR [SV: stroke volume; C: constant value; PP: Pulse Pressure; HR: Heart Rate]. Since studies have shown that there is a greater correlation between SV and PWTT than between SV and PP, the CO calculation was stated as followed as a result of the PWTT information: CO = SV × HR= C × (α × PWTT ＋ β) × HR = esCCO [α, β: experimental constants].