Upper Airway Obstruction
There is not a more terrifying scenario in medicine than upper airway obstruction.
Since the airway at the level of the vocal cords is approximately one inch in diameter, obstruction is common and can rapidly lead to asphyxia (strangulation).
The problem is compounded by the anatomy of the airway. The one-inch diameter of the trachea, or “windpipe”, is further narrowed by the V-shaped vocal cords which are present in a horizontal position at the base of the neck. This narrow structure is easily occluded by swelling of the vocal cords secondary to an allergic reaction or infection, foreign bodies, such as piece of meat or a toy, or a tumor.
Unfortunately, the response of a patient with upper airway obstruction is actually an increased respiratory effort. This then leads to increased negative intrathoracic pressure, which tends to draw a foreign body further into the lungs, thus worsening the situation. Once the airway is occluded, airflow ceases and arterial oxygen levels drop precipitously. If the airways is not reestablished within five minutes, permanent brain damage occurs and oxygen delivery to the heart is markedly reduced. The heart muscle then becomes unstable and a fatal cardiac arrhythmia ensues.
The treatment of upper airway obstruction involves immediate establishment of an airway. Use of the Heimlich Maneuver (a sudden increase in pressure on the surface of the abdomen) may dislodge a foreign body and reopen the airway. Vocal cord edema (swelling) or a tumor require the opening of the trachea at the base of the neck using a sharp instrument such as a knife or a ballpoint pen. A tube is then inserted which allows the movement of air in and out of the lungs. This type of maneuver can prevent a fatal outcome.
Upper airway obstruction is one of the few emergencies in medicine where the outcome is immediately obvious. Successful placement of an airway generally results in full recovery if accomplished within five minutes of the obstructive event. On the other hand, failure to successfully establish the airway promptly results in permanent brain damage or sudden death.
© Sept. 2006. James F. Lineback, MD, FCCP. All Rights Reserved. Excerpt from monthly Newsletter.