The "vapours," fainting, and the vagal reflex

Health Professional

In old movies, actresses would put their hands up to their foreheads with the palm faced out before passing out upon the delivery of any bad news, or as a sure sign of an unsuspected pregnancy (or a bad plot). Rarely in these movies did a man faint "dead away," except for comic relief upon "not getting shot."

In real-life situations, though, fainting can represent a problem and is the cause of a huge amount of expenditure of health care dollars and patient concern. Indeed, one of the first consultations that I received after opening my office was from a pediatrician. A 17 year-old male suffered an apparent cardiac arrest in his office after a tetanus shot. It still amazes me that the simple sight of a needle can bring about such awesome changes in human physiology. In this case, the young man awoke with a rather sheepish grin. The problem: he and many members of his family have "strong vagal tone."

Each year, there seems to be another effort at creating a pacemaker for people troubled by such fainting spells, and this year is no different  as it brings  a claim from England that there is now such a pacemaker. Fortunately, the strength of vagal tone may be associated with longer rather than shorter length of life. In patients that have heart attacks, the patients with the better vagal tone are those who have the best survival. For this reason, doctors will ordinarily reassure patients that such spells are not a major problem.

Boxers learn that a punch to the solar plexus (located in the upper abdomen) can disable an opponent as easily as a punch delivered to the jaw. This is because this type of trauma will also stimulate the vagal nerve responsible for slowing the heart and lowering the blood pressure. In the same manner, stimulation of this vagal nerve by a gastrointestinal illness, by eye pain, or even when an abscess is drained may make us feel as if we are going to pass out. This may happen quite often in some people, and, as a result, some scientists have advocated different forms of pacemakers to prevent the problem. Recently,  a group of scientists   advocated a new kind of pacemaker in the United Kingdom. In my experience thus far, these efforts work no better than the old fashioned remedy of "smelling salts."

I did a stress test this morning on a patient who had a history of fainting spells. He reminded me that the way he avoided them at times was by looking away. He used to faint at the sight of blood or if someone took a blood test from him and he watched. He found that looking away from the needle (and letting the technician do her work without his "help") did wonders (as long as he did not see anyone else having his or her blood drawn). He did fine on his stress test. Most of the time such "high vagal tone" requires no treatment other than reassurance, though, on occasion, we do have to use drugs such as atropine or belladonna alkaloids.