During general anesthesia the basic non-invasive monitoring of hemodynamic parameters (blood pressure, O2-saturation, cardiogram) is crucial. It can be enhanced to so called "extended hemodynamic monitoring" depending on the operation and patient. Frequently an invasive arterial cannula is used to provide continuous information on the blood pressure. This invasive method is very accurate and clinically established, but can be linked to adverse effects e.g. reduction of the circulation flow distal of the canulla, haematoma, infection etc. ccNexfin (Edwards Lifescience) is a finger cuff measuring the blood pressure in a non-invasive manner. It thus offers beat-to-beat information even about the extended hemodynamic parameters as cardiac output (CO), cardiac index (CI), stroke volume (SV), stroke volume index (SVI) and stroke volume variation (SSV), if connected to the clinical platform EV1000 (Edwards Lifescience).

Assuming that the two methods are equal we plan to measure extended hemodynamic parameters before, during induction and during ongoing anesthesia both invasive and non-invasive. Data will be recorded every 30sec.

Clinical evaluation of the ccNexfin technology in respect to extended hemodynamic parameters is to our knowledge rare and further assessment in this field is needed to offer patients a potentially equally reliable but less invasive monitoring. Furthermore the study should model the effect of remifentanil, propofol or its combination on haemodynamics .

Inclusion Criteria:

• elective surgery with the necessity of an arterial catheter

Exclusion Criteria:

• patient not consented
• peripheral vascular disease

Patients that get an elective surgery under general anesthesia