Goal-directed intraoperative fluid therapy monitored by Esophageal Doppler identifies volume-responders, thereby decreasing length of stay in hospital in orthopedic [Sinclair 1997], cardiac [Mythen 1995], and abdominal surgery patients [Gan 2002, Wakeling 2005, Noblett 2006]. However, all these studies have been performed with a colloid to be the substance applied. Thus, it has been questioned whether monitoring with the Esophageal Doppler monitor, or the application of additional colloid improved outcome [Horowitz, Kumar 2003].