Second-Generation Laryngeal Mask Airway vs Endotracheal Intubation in Adult Liver Transplantation

Inclusion Criteria: * Adults aged 18 to 75 years, regardless of sex. * Clinical diagnosis of end-stage liver disease, including hepatocellular carcinoma, and scheduled to undergo a first elective allogeneic liver transplantation using the conventional or piggyback technique. Participants with hepatocellular carcinoma must meet the indications for liver transplantation specified in the Chinese Clinical Practice Guidelines for Liver Transplantation for Hepatocellular Carcinoma (2021 Edition). Causes of end-stage liver disease may include, but are not limited to, viral hepatitis-related cirrhosis, alcoholic cirrhosis, and autoimmune liver disease. * No severe airway abnormality on preoperative assessment, including severe laryngeal malformation, laryngeal tumor, restricted neck movement, mouth opening less than 3 cm, thyromental distance less than 6.5 cm, or Mallampati class IV. * No history or evidence of a high risk of pulmonary aspiration, including gastric retention, intestinal obstruction, severe gastroesophageal reflux disease, or active upper gastrointestinal bleeding. * No severe cardiac, pulmonary, or renal organ failure, except for liver disease-related kidney injury, and meeting all of the following criteria: * Left ventricular ejection fraction of at least 50% on echocardiography performed within 3 months before surgery, without moderate or severe valvular stenosis or regurgitation, severe ventricular hypertrophy or dilation, regional wall-motion abnormalities, or a large pericardial effusion. * No severe and uncorrectable coronary artery stenosis involving the left main coronary artery or multiple major coronary vessels. * No acute heart failure or myocardial infarction within 6 months before surgery. * No severe or uncontrolled chronic obstructive or restrictive pulmonary disease, with FEV1/FVC greater than 70% and vital capacity greater than 80% of the predicted value. * No hepatopulmonary syndrome or severe pulmonary hypertension at rest, with mean pulmonary artery pressure no greater than 35 mmHg. * No active pulmonary infection. * Estimated glomerular filtration rate of at least 60 mL/min/1.73 m2, corresponding to chronic kidney disease stage 1 or 2. * Body mass index no greater than 30 kg/m2. * Model for End-Stage Liver Disease score no greater than 30. * The participant and family members are adequately informed, willing and able to comply with all study procedures, and provide written informed consent. Exclusion Criteria: * Emergency liver transplantation or repeat liver transplantation. * Contraindication to a laryngeal mask airway or endotracheal intubation, or a known or anticipated difficult airway, including severe airway obstruction, severe cervical spine injury, laryngeal edema, or restricted mouth opening. * Previous esophageal or pharyngeal/laryngeal surgery. * High risk of regurgitation or pulmonary aspiration, including severe gastroesophageal reflux disease, markedly increased intra-abdominal pressure due to massive ascites, an inadequately fasted state, or a full stomach. * History of two or more upper abdominal operations with extensive intra-abdominal adhesions and an expected operative duration greater than 8 hours. * Severe preoperative pulmonary disease meeting criteria for severe respiratory failure, severe chronic obstructive pulmonary disease, or severe restrictive pulmonary disease that is expected to limit tolerance of increased airway pressure. * Severe preoperative cardiac disease, including unstable angina or malignant arrhythmia, severe heart failure, or severe pulmonary hypertension. * Poorly controlled hypertension, defined as resting blood pressure not adequately controlled to 140/90 mmHg or lower despite systematic pharmacologic treatment. * Other severe disease that may limit participation, including poorly controlled diabetes mellitus with glycated hemoglobin greater than 8% after treatment, pulmonary embolism, transient ischemic attack, or stroke. * Known allergy to any anesthetic medication planned in the protocol, including propofol, rocuronium, or sufentanil, or to silicone or polyvinyl chloride materials used in the laryngeal mask airway. * For participants with hepatocellular carcinoma, severe adverse effects after preoperative chemotherapy, radiotherapy, targeted therapy, or immunotherapy, such as severe bone marrow suppression or acute deterioration of hepatic or renal function, resulting in inability to tolerate surgery or anesthesia. * Another concurrent or previously diagnosed malignancy that has not been cured within the previous 5 years, except for malignancies considered clinically curable, such as cervical carcinoma in situ or basal cell carcinoma of the skin. * History of psychiatric illness or cognitive impairment, including epilepsy or dementia, that prevents the participant from understanding or complying with study procedures. * Pregnancy or breastfeeding. * Participation in another interventional clinical study within 3 months before enrollment. * Any other condition that, in the investigator's judgment, may substantially increase study-related risk or interfere with evaluation of study outcomes.