Some surgical procedures require general anesthesia (i.e., the patient is 'asleep'). When under general anesthesia, these patients' airways must be managed to ensure continuous flow of oxygen to the lungs, and in most cases, delivery of anesthetic gases to the lungs. Most often for airway management under general anesthesia, a plastic breathing tube is placed though the voicebox ("larynx") into the windpipe ("trachea"), a process known as "tracheal intubation". To safely intubate, the larynx must first be exposed. In many cases, this is achieved by using a device known as a direct laryngoscope, which is like a curved, lighted tongue depressor. It is used to gently move the tongue out of the way, to expose the larynx. When the larynx is easily seen, passing the breathing tube is usually also easy. Unfortunately, in 2-5% of cases, it is difficult or impossible to view the larynx using the direct laryngoscope. This then creates difficulty with tube passage. A number of options exist to deal with this situation, including, within the last 10 years, a class of device called "video laryngoscopes". These devices use a small video chip located towards the end of the blade, which, by providing transmission of an image of the larynx 'around the corner' to a screen outside the patient, enable a view to be obtained (when no such view could be obtained with direct laryngoscope). With the larynx now indirectly visualized, tube passage can proceed. However, it's not that easy. When using these 'around the corner' videolaryngoscopes, tube passage can be more difficult, as the tube must be guided around a 90 degree bend from the mouth to the trachea, which sits at right angles to the mouth. Less difficulty occurs with tube passage when the direct laryngoscope is used because the blade compresses the tongue out of the way, creating a straight line from teeth to the larynx and windpipe beyond.