75 patients undergoing UGC surgery (25 each of the three most common cancer types of UGC) will be included. This study will use a novel skin flushing measuring method called laser speckle contrast imaging (LSCI) to measure skin blood flow of the forehead. LSCI is a real-time and non-touch measuring device capable of measuring blood flow on a large field surface (15 cm x 20 cm). In parallel, inflammatory and hormonal stress biomarkers considered to be associated with SSR, will be measured. In this study, it is hypothesized, that by correlating a new method of quantifiable flushing measurement and known biomarkers, it is possible to relate the extent of flushing to the severity of hypotension and MTS and by proxy the extent of complications.