This article does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (December 2007)

Fiber optic intubation is a specialized technique within the field of anesthesiology. The purpose fiber-optic intubation is to facilitate the insertion of an endotracheal tube through the mouth or nose, and into the trachea (wind-pipe) of suitably prepared patient.

General anesthesia (unconsciousness) is required for many surgical procedures. However, in addition to effecting the brain by removing awareness, general anesthesia has a profound impact on other systems of the body, such as the respiratory and cardiovascular systems. It can be difficult or impossible to separate the desired action of anesthesia on the neurological system, from the less-desirable side effects that are caused to the breathing and circulation.

The impact of anesthesia on breathing (respiration) is profound. Under normal circumstances the patients’ breathing may reduce or stop entirely. In addition the airway (the nose, mouth and throat) may become blocked, usually due to the tongue relaxing backward and obstructing the air passages (colloquially known as ‘swallowing your tongue’). This situation must be promptly corrected by the anesthesiologist, or else the patient will become deprived of oxygen and severe harm may result. This correction is usually accomplished by conventional intubation, followed by artificial breathing (mechanical ventilation).

However, if it proves difficult or impossible for the anesthesiologist to correctly place the endo-tracheal tube, and anesthesia has already abolished the patients’ normal breathing, then a crisis may develop where the patient is becoming deprived of oxygen, and the anesthesiologist is unable to remedy the problem. In the worst-case scenario, death or brain damage may occur within a few minutes.

Difficulty in placing the endo-tracheal tube is more likely in patients with an abnormal airway, such as an inability to open the mouth or move the upper spine, patients with tumors or swelling within the throat, the overweight, or those with relatively short jawbone or large neck.

In these patients who are at high risk of difficulty occurring, it is sensible to avoid administering a general anesthetic and precipitating a crisis. The alternate approach is to insert the endo-tracheal tube before the general anesthetic, so that normal breathing continues until success in tube placement has been achieved. Then general anesthesia can be administered with the knowledge that maintenance of the open airway is guaranteed.

Unfortunately, it is impossible for the awake patient to tolerate the insertion of the curved metal plate of the laryngoscope into the throat and the insertion of the endo-tracheal tube into the larynx without severe coughing, gagging and distress to be caused.

Therefore, the technique of fiber-optic intubation is used to overcome these problems. First, the patient is sedated, so that distress and explicit memory is reduced, and tolerance is improved. Then local anesthesia is applied to the airway and throat, so that the surfaces become numb, gagging is reduced, and tolerance is further increased. Then an endoscope is introduced through the nose or mouth, which contains fiber-optic glass threads to enable the anesthesiologist to ‘see around corners’. With this, the anesthesiologist can navigate through the patients nose, throat and voice box and into the trachea by actually seeing and finding a clear path through these structures. If the endo-tracheal tube has been placed around the endoscope prior to commencing the procedure, then once the trachea is visualized, the tube can be made to follow into the correct position. The tube following the endoscope into position is analogous to a train following railway tracks, and is therefore referred to as ‘railroading’.

Once the endo-tracheal tube is in its correct position, then general anesthesia and surgery can proceed as normal.