Inclusion Criteria:  Pediatric patients younger than 18 yr old who will be operated in our hospital and intubated with cuffed tubes numbered 4.5, 5.0, and 5.5 under general anesthesia are included in this study.  Exclusion Criteria:  ASA physical status score of III and IV, Tracheostomy, airway obstruction or other airway anatomical abnormalities, Difficult intubation prediction, History of airway hyperreactivity or bronchial asthma, Body mass index above the 85th percentile and below the 5th percentile, Patients whose parents were unable to read, understand and sign the consent form or whose parents did not want to sign the consent form will not included in the study.