Effects of operator experience and method in the inflation of endotracheal tube pilot balloon on cuff pressure

INTERVENTION: 1)Operators were divided into following groups according to experiences: Group T1 (n=50): Anesthesia technician with less (than two years) experience (5 operators) Group T2 (n=50): Anesthesia technician with more (than two years) experience (5 operators) Group A1 (n=50): Research assistant doctor with less (than three years) experience (5 operators) Group A2 (n=50): Research assistant doctor with more (than three years) experience (5 operators) 2) After intubation, endotracheal tube cuff was inflated by two different methods, until the leakage sound was discontinuated or pilot balloon palpation by operators. Each of the operator from these groups were to conduct the application on 10 patients, and endotracheal tube cuffs were inflated according to leakage sound in half of the patients (n=5) and pilot balloon palpation in the other half (n=5). 3) After endotracheal entubation, cuff was inflated immediately. cuff pressures were measured at the 5th and 60th minutes of endotracheal intubation and immediately before emergence from anesthesia CONDITION: endotracheal tube cuff pressure PRIMARY OUTCOME: endotracheal cuff pressure (via aneroid manometer) ; In case the cuff pressure was above 30 cmH2O or below 20 cmH2O, the pressure was intervened to bring back to normal limits SECONDARY OUTCOME: Postoperative complaint ; (sore throat, hoarseness of voice, coughing, and dysphagia) INCLUSION CRITERIA: 16‐60 years old, ASA status I‐III, elective surgery in supine position, endotracheal tube inner diameter 7 ‐8.5 mm,