Lactate Blood Increase

Fluid therapy during surgery is an important factor that is related to long term mortality and morbidity and it's directly related to tissue perfusion as well. The main target in any surgery is what is the optimum fluid therapy to maintain the tissue perfusion and the precise balance between hazardous effects of hypervolemia that may cause delayed wound healing due to surgical anastomosis disruption or being hypovolemic that may cause tissue ischemia as acute kidney injury. Fluid management guidance changed from static methods like central venous pressure into dynamic methods like pulse pressure variation (PPV) and stroke volume variation (SVV), which are now the most famous dynamic measures. Electrical cardiometry is a non-invasive cardiac output monitor which uses electrical cardiometry, now a commonly used device, to measure SVV which can be used to guide fluid therapy during surgeries. Now robotic assisted surgery is a common method in preforming many surgeries especially urological, since it's associated with numerous desirable outcomes including shorter post-operative stay and faster return to preoperative function. With considerations related to severe Trendelenburg position and increased intra-abdominal pressure due to pneumo-peritoneum, robotic assisted surgeries are associated with many challenges in anesthesia especially the fluid therapy. Fluid therapy in robotic surgeries is an area with growing research focus that need further exploration while there are established guidelines for fluid management in traditional surgeries, the optimal protocols for robotic surgeries are less well defined, needing more research. We aim at this study to investigate the impact of liberal versus restricted fluid intake on the tissue perfusion reflected by serum lactate \& creatinine clearance, while guiding therapy through electrical cardiometry, to reach optimum fluid protocol in prostatic robotic surgeries.

During major surgical procedures performed under general anesthesia, changes in blood flow and oxygen delivery to tissues may occur due to blood loss, hemodynamic fluctuations, and anesthesia-related physiological effects. These changes can lead to impaired tissue perfusion, which is commonly reflected by increased arterial lactate levels. However, lactate measurements are intermittent and may not detect early perfusion abnormalities. This prospective observational study aims to investigate the relationship between submental tissue oxygenation measured by near-infrared spectroscopy (NIRS), microvascular reactivity assessed by the vascular occlusion test, and arterial lactate levels during major surgery. Adult patients undergoing major abdominal, neurosurgical, or orthopedic procedures will be monitored intraoperatively using non-invasive NIRS techniques, while arterial blood gas analyses will be performed as part of routine clinical care. The study does not involve any changes to standard anesthesia or surgical management. All treatments and clinical decisions will be made by the responsible care team according to routine practice. By evaluating non-invasive indicators of tissue oxygenation and microvascular function, this study aims to improve the understanding of early intraoperative tissue perfusion changes and their association with metabolic markers.

The aim of the proposed study is to investigate the effect of increased plasma lactate concentrations on the heart and brain's metabolism of other energy sources, primarily glucose in the brain and glucose and FFA in the heart. The investigator hypothesize that: * An acute increase in lactate plasma concentration will decrease cerebral glucose uptake and increase cerebral blood flow * An acute increase in lactate plasma concentration will decrease palmitate and glucose uptake in the myocardium, and increase myocardial perfusion