There is no strong evidence about the optimal fluid resuscitation for the patients undergoing major surgeries. Avoiding excess fluid resuscitation in the perioperative period is essential for reducing postoperative complications, morbidity and long-term mortality. In the perioperative period, ANP is released with increased wall stress in the cardiac atrium due to excess fluid loading. With the release of ANP, damage occurs in the glycocalyx layer, which is the structure primarily responsible for the permeability in the vascular endothelium.~Thus, the amount of ANP released from atrium and heparan sulfate, syndecan 1, hyaluronan in the glycocalyx layer structure increases in the blood.~The aim of this study is to compare changes in the glycocalyx structure by measuring the blood levels of ANP and heparan sulfate, hyaluronan and syndecan 1, which form the glycocalyx structure on the patients who received the liberal and restrictive fluid treatments during major urological surgeries. The blood samples will be taken at the beginning and at the end of the surgery.~The primary outcome of this study is the increase in ANP levels and heparan sulfate , hyaluronic acid, syndecan 1 levels which are the glycocalyx damage products in blood.~Secondary outcomes are intraoperative advanced hemodynamic cardiac measurement values, the amount of blood and blood products replaced to patients, duration of intensive care stay, duration of hospital stay, cardiac and respiratory complications, gastrointestinal complications, urinary complications, surgical complications such as anastomotic leaks, wound infection and fistula.
The aim of this study is to compare the effect of the liberal and restrictive fluid treatments which are routinely performed in major urological surgeries in the perioperative period on ANP release and the endothelial glycocalyx layer.~In the study, the investigators aimed to compare changes in the glycocalyx structure by measuring the blood levels of ANP and heparan sulfate, hyaluronan and syndecan 1, which form the glycocalyx structure on the patients who received the liberal and restrictive fluid treatments during major urological surgeries.