For this purpose, there will be four questionaires. After informed consent, the first questionaire will cover the patient's history, risk factors and previous operations. The second questionaire will cover intraoperative fluid management, documented with the actual operation step. Furthermore, it will also intraoperative complications, cardiovascular-active medication. For closer monitoring, data from Picco will also be included. The third questionaire will be complete in the ICU covering similar content as the second questionaire. The last questionaire will cover the patient's progress on the general ward. Fluid management and tube feeding, as well as general postoperative complication and flap specific complications will be noted.