Comparison of learning curve between visual intubation LMA and common LMA: a single-center, prospective randomized, parallel control study

INTERVENTION: Common intubation LMA group:Common intubation laryngeal mask;Visual intubation LMA group:Visual intubation laryngeal mask; CONDITION: airway management education PRIMARY OUTCOME: One‐time insertion success rate; SECONDARY OUTCOME: Compare the time required for successful placement of LMA between the two groups;Fiberoptic bronchoscope rating;Success rate of in situ adjustment and re‐installation;Rate of tracheal intubation;Hemodynamic indexes before anesthesia induction (T0), 1 min after injection of induction drug (T1), 2 min after injection of induction drug (T2), 3 min after injection of induction drug (T3), 1 min after placement of LMA (T4), 2 min after placement of LMA (T5), and 3 min after placement of LMA (T6);Compare the throat complications of the two groups within 24 hours after operation: nausea and vomiting, throat pain, throat bleeding, dry throat cough and other discomfort;Bleeding can be seen by naked eyes of LMA; INCLUSION CRITERIA: 1. American Society of Anesthesiologists (ASA) Class I ‐ II; 2. Age 18‐70; 3. Cardiac function grade I ‐ II; 4. BMI 18‐25 kg/m2; 5. The operation time is less than 3 hours; 6. Sign the informed consent form voluntarily.