An unblinded anesthesia attending associated with the study prepared the FOS and ETT according to the randomization, and advanced the FOS into the trachea and the ETT into the posterior pharynx. The anesthesia provider advancing the ETT was always one of the trainees: student nurse anesthetists (SRNA) or resident who was not a part of the study and was blinded to whether or not the ETT has been rotated 90°counterclockwise. The attending member of the research team observed as the ETT was advanced by the trainee and made a note of whether or not the ETT got hung up. If it did, the research team member withdrew the ETT 2 cm, rotated it 90° CCR, and allowed the trainee to advance the ETT one or more times, noting the results.