Nonintubated Anesthesia for Adult Cardiac Surgery With Cardiopulmonary Bypass

Inclusion Criteria: * Age 18 years or older, regardless of sex * Scheduled to undergo elective cardiac valve surgery with cardiopulmonary bypass * Considered eligible for either the non-intubated supraglottic airway anesthesia with early restoration of spontaneous breathing (NIA) strategy or the conventional anesthesia strategy, based on a joint preoperative assessment by the anesthesiology and cardiac surgery teams * Relatively stable vital signs and able to complete the required perioperative assessments and follow-up * Willing to participate in the study and able to provide written informed consent personally or through a legally authorized representative Exclusion Criteria: * Emergency or urgent cardiac surgery * Severe pulmonary infection, severe respiratory failure, or another preoperative condition that clearly precludes use of the NIA strategy * Severe preoperative hemodynamic instability requiring high-dose vasoactive medications or mechanical circulatory support * Known difficult airway, high risk of aspiration, or another anesthetic contraindication to the NIA strategy * Severe hepatic, renal, or neurological disease that may substantially affect the assessment of perioperative outcomes * Pregnant or breastfeeding * Previous or concurrent participation in another interventional clinical trial that may affect the results of this study, if the participant remains within the relevant intervention or carryover period * Any other protocol-specified clinical condition that, in the opinion of the investigator, makes the participant unsuitable for enrollment