Section II. ENDOTRACHEAL TUBE
An endotracheal tube (ET) is a tube inserted into the trachea for administration of
anesthesia, maintenance of an airway, aspirations of secretions, ventilation of the lungs,
or prevention of the entrance of foreign material into the tracheobronchial tree. The two
types of ETs dealt with in this lesson are the orotracheal tube and the nasotracheal
tube. The orotracheal tube is inserted through the mouth into the trachea. The
nasotracheal tube is inserted through the nose into the trachea. In this lesson, both the
orotracheal tube and the nasotracheal tube are used to establish an airway.
ADVANTAGES/DISADVANTAGES OF ET
a. Advantages of ET. The chief advantage is that the endotracheal tube
provides an unobstructed airway if the tube is properly placed. Air is channeled through
the larynx and trachea to the lungs where it is needed. In normal breathing, some air
breathed remains in the larynx and trachea where the air is unused. The space holding
the unused air is called anatomic dead space, and the endotracheal tube reduces that
space by about 50 percent. Once inserted, the ET prevents the casualty from breathing
in secretions such as blood, stomach contents and bowel contents. The ET also makes
positive pressure breathing (assisted or controlled) easier without gastric inflation.
b. Disadvantages of ET. With the ET in place, air goes directly through the
mouth without being warmed, humidified, or filtered--all of which normally take place in
the nasal passages. It is possible to cause further injury to the casualty by accidentally
inserting the tube into the wrong area. A tube inserted into the esophagus, for example,
can cause the airway to be completely obstructed. Also, the presence of the tube may
be such an irritant to the casualty's body that he may have breathing problems. The
tube may cause bronchial spasms or increase the production of mucous, both make it
more difficult for air to reach the casualty's lungs.
INDICATIONS/CONTRAINDICATIONS FOR USE OF ET
a. Indications. Indications for using the endotracheal tube are the same as for
using the esophageal obturator airway--casualty in deep coma, casualty with shallow
respirations, casualty has progressive cyanosis, or casualty has cardiopulmonary arrest.
Additionally, use the ET when preparing a person before surgery for anesthesia. The
ET is used in all types of surgery where the casualty's position makes it impossible to
use a mask; for example, the prone (lying face downward), lateral (lying on side with top
knee bent for balance), or sitting positions. The ET is used if a tight mask fit is not
possible due to "atypical" (abnormal) facial contours caused by disease, obesity, etc.