Goal of the Study is to Study the precision of semi-invasive cardiac index monitoring by means of the ProAQT (PULSION Medical Systems SE) sensor, whereby the pulmonary artery catheter will serve as gold standard.

Goal of the Study is to Study the precision of semi-invasive cardiac index monitoring by means of the ProAQT (PULSION Medical Systems SE) sensor, whereby the pulmonary artery catheter will serve as gold standard.

Measurements will be performed contemporaly with both devices every 4 hours and all clinical and hemodynmaic parameters will be recorded, including but not limited to central venous pressure, wege pressure, mechanical ventilation pressures, blood pressures, volume balance as well as vasoaktive medikation doses. This precise evaluation shall serve to evaluate the precision of the ProAQT to estimate the cardiac index under different clinical situation in the intensive care unit. A precision difference of below 30% between both methods will be regarded as clinically irrelevant, suggesting equipoise between both methods.

Inclusion Criteria:

• In situ pulmonary artery catheter
• Above 16 years of age
• At least 36 hours of continuous hemodynamic monitoring with the pulmonary artery catheter planed

Exclusion Criteria:

• Patients with:
• Permanent or pesisting Atrial Fibrilation or Ventricular Arrythmias
• Moderate to Severe Aortic Insuficiency or Aortic Stenosis
• Intravascular Cardiac Assist Device
• Planed removal of the pulmonary artery catheter <36 hours

All Patients admitted to the Medical ICU of the University Hospital Zürich complying with the inclusion and exclusion criteria