The goal of this prospective, multicenter, randomized clinical trial is to learn whether a nonintubated supraglottic airway anesthesia strategy with early restoration of spontaneous breathing can reduce postoperative pulmonary complications and improve early recovery in adults undergoing elective cardiac surgery with cardiopulmonary bypass.

The main questions it aims to answer are whether, compared with conventional endotracheal fast-track anesthesia, the nonintubated strategy can reduce pulmonary complications within 30 days after surgery, reduce the need for postoperative invasive mechanical ventilation and other respiratory support, and shorten the time spent in the intensive care unit.

Participants will be randomly assigned to undergo cardiac surgery using either a standardized nonintubated supraglottic airway anesthesia strategy with early restoration of spontaneous breathing or a conventional endotracheal fast-track anesthesia strategy. Both groups will receive standardized perioperative care, with objective criteria for airway removal and readiness for discharge from the intensive care unit. Endotracheal intubation or escalation of respiratory and circulatory support will be performed whenever clinically necessary.

Participants will be followed from screening through hospitalization, at 30 days after surgery, and for up to 1 year. Routine perioperative data and key postoperative outcomes, including pulmonary complications, respiratory support, intensive care unit stay, major organ complications, safety events, recovery, rehospitalization, and survival, will be collected.