Orotracheal intubation refers to the placement of a breathing tube into the trachea through the mouth, or orally. In an emergency or critical care situation, this method of providing respiratory assistance is preferred over the alternatives of nasotracheal intubation — where the tube is inserted through the nose — or an emergency tracheotomy or cricothyroidotomy where the tube is inserted directly into an emergency opening made in the trachea. Orotracheal intubation is considered the best choice as it allows insertion of a larger diameter airway tube than does nasotracheal intubation or intubation via cricothyroidectomy and presents fewer side effects than does an emergency tracheotomy. Often referred to by only its shortened name — intubation — this procedure constitutes the "A" or airway of the ABC's of emergency care. Without establishing the means to provide adequate oxygen to the brain and body, any additional medical care or intervention is fruitless.
A laryngoscope fitted with an appropriate blade is the essential piece of equipment necessary to perform an orotracheal intubation. This device is a metal cylinder that acts as the handle of the full laryngoscope during the procedure and provides an energy supply for a small blade bulb to assist in intubation. Laryngoscope blades are available in different sizes and are of two general types, curved or straight. The curved, or Macintosh, blade is used most commonly although the actual use of a given blade depends upon availability and preference. Regardless of the choice of blade, the laryngoscope is always held in the left hand.
In order to perform an orotracheal intubation, the doctor, paramedic or advanced cardiac life support (ACLS) provider stands over the patient's head — upside down to the patient's anatomy — and uses the blade of the laryngoscope to lift the tongue and epiglottis out of the way. The epiglottis protects the top of the trachea, or airway, from the accidental entry of food or liquid. When lifted up and out of the way, the vocal cords at the top of the trachea can be identified with the lighted laryngoscope blade and the breathing tube introduced into the trachea. As the esophagus — the tube to the stomach — is adjacent to the trachea, an attempted orotracheal intubation can easily introduce the breathing tube into the esophagus instead of the trachea. There are several types of evaluations used to confirm correct placement of the breathing tube, including listening for breath sounds in the proper location and a chest x-ray, when available.
The breathing tube is held in proper position by inflating a small bulb located near the end of the tube. The tube is taped where it emerges from the patient's mouth and additional taping is performed to further secure the endotracheal tube. As noted above, proper placement of the endotracheal tube is always confirmed with a chest x-ray as soon as possible.