Intraoperative hemodynamic instability (IOHI) is a common occurrence during cardiac surgery and is associated with organ hypoperfusion. However, the specific impact of IOHI on composite adverse outcomes remains unclear. This prospective cohort study aims to evaluate the association between intraoperative hemodynamic instability (defined as MAP \< 65 mmHg or vasopressor requirement) and major postoperative complications (Delirium, Acute Kidney Injury, Stroke, or Mortality) in adult patients undergoing elective cardiac surgery with cardiopulmonary bypass.