Patients will be intubated by an experienced anesthesiologists. Anesthesiologist first uses Macintosh laryngoscope then KingsVision videolaryngoscope and lastly C-MAC videolaryngoscope to intubate patients. Cormack-Lehane scores, the time from the start of laryngoscopy to visualization of the vocal cords and the time from the visualization of the vocals from the successful intubation will be recorded. The success of the intubation will be assessed with bilateral chest auscultation. If visualization of the vocal cords or placing of the endotracheal tube was not successful after 60 seconds with a particular laryngoscope, it will be left out and patient will be ventilated for 1 minutes and then pass to other laryngoscopes.

Patients will be preoxygenated with 100% oxygen for 3 minutes before the anesthesia induction. After induction when the train of four ratio reaches %0, patients will be intubated by one of three anesthesiologists with at least 10 years of experience. The anesthesiologist first will use the Macintosh laryngoscope then KingsVisionTM videolaryngoscope and lastly C-MAC videolaryngoscope to intubate the patients. The Cormack-Lehane scores observed during each laryngoscopy will be recorded

Patients will be preoxygenated with 100% oxygen for 3 minutes before the anesthesia induction. After induction when the train of four ratio reaches %0, patients will be intubated by one of three anesthesiologists with at least 10 years of experience. The anesthesiologist first will use the Macintosh laryngoscope then KingsVisionTM videolaryngoscope and lastly C-MAC videolaryngoscope to intubate the patients. The time from the start of laryngoscopy to the visualization of the vocal cords and the time from the visualization of the vocals from the successful intubation observed during each laryngoscopy will be recorded.