The maintenance of arterial blood pressure is essential for organ perfusion pressure. Intraoperative hypotension is a frequent complication both after induction and during maintenance of anaesthesia, ranging from 5% to 75% depending on the chosen definition. Tissue hypoperfusion exposes to the occurrence of a systemic inflammatory response syndrome and is a key determinant of postoperative complications. Persistent intraoperative hypotension has been reported as an important prognostic factor of postoperative morbidity and mortality. Adequate treatment of arterial hypotension is therefore of particular importance during surgery, but optimal strategy of intraoperative blood pressure management remains undetermined, especially in high-risk patients. Target ranges for arterial pressure are not clearly defined, and hypotension is usually defined as a systolic pressure of less than 80 mmHg or a decrease of more than 40% from baseline.