Hypotension with potentially serious consequences for organ perfusion is a common complication in extracorporeal procedures such as heart-lung-machine. The exact reasons for this are still insufficiently clarified. Probably periinterventional vasorelaxant released substances play a crucial role in these procedures. These substances could be due to contact of blood cells with the Membrane in the HLM arise. In this project the hypothesis will be checked, if EETs / DHETs are released by Erythrocytes during this extracorporeal procedure and thus act as potential candidate products for the result of hypotonic phases during usage of heart-lung-machine.

We will determine differences in RBC fatty acids profiling in patients before and after heart-lung-machine intervention. RBC fatty acids profiling will be achieved by using targeted HPLC-MS mass spectrometry.

It is believed that during HLM there is an increase in EETs / DHETs in the serum and in the erythrocytes. It is believed that shear forces play an important role in the release of erythrocyte EETs / DHETs.

Inclusion Criteria:

• Patients who are undergoing an operation with the aid of the heart-lung machine for cardiac surgery
• Age over 18 years
• Ability to consent
• There is a written consent of the study participant

Exclusion Criteria:

•none