Hypotension prediction index (HPI) was applied in various types of non-cardiac surgery with convincing benefits of preventing hypotensive events and clinical sequelae. Although HPI was validated in cardiac surgery, its clinical benefits are not proven yet. We aim to evaluate its effects on intraoperative hypotension and postoperative adverse events in cardiac surgery. In this randomized, single-blind trial, we will enroll adults scheduled for elective primary cardiac surgery under general anesthesia. Participants will be randomly assigned to intraoperative HPI-guided or non-HPI-guided hemodynamic management. The primary endpoint is the time-weighted average intraoperative hypotension below a mean arterial pressure threshold of 65 mmHg. The secondary endpoints are postoperative complications.