1985 through December 1986 included a total of 117 re- sponses for trauma. Our average ground time was only 16.2 minutes. Five patients were pronounced dead at the scene of the accident, and 15 more died in the ED, for an initial mortality rate of 17% (NS, P > .05). Again, although it is difficult to compare different patient populations, the sim- ilarity between our results and those of Anderson suggests that the "benefit" of having a physician aboard the heli- copter is extremely difficult to demonstrate. We believe that the primary contribution of the physician to the care of the patient with AMI or severe multiple trauma is in the ED and the operating room.

Moreover, this comparison tends to support our clinical

suspicion that most physicians spend inappropriately long periods in the field. Dr Anderson's program (with physi- cians) spent twice as long at each scene as did our program (with physicians on only 5% of flights) with no difference in outcome.

Thomas J Poulton, MD, FAAP, FCCP, FACP Pamela J Gutierrez, RN, CCRN, CEN, NREMT-P Daniel J Schwabe, RN, NREMT-P Life Flight Saint Joseph Hospital Omaha, Nebraska

Remember the Physical Examination

To the Editor: The article "Differentiation of Ventricular Tachycardia

from Supraventricular Tachycardia with Aberration: Value of the Clinical History" [January 1987; 16:40-43] by Baerman et al raises several interesting points but fails to mention one very important one: examination of the patient. In a time when medicine is becoming increasingly sophisticated it behooves us to remember the physical examination.

As mentioned by the authors, atrial-ventricular dissocia- tion is highly suggestive that a wide-complex tachycardia is ventricular in origin. One important clue in determining atrial-ventricular dissociation is the pattern of the jugular venous pulse. The "a" wave in the venous pulse is caused by venous distension secondary to right atrial systole. While it is often not readily distinguishable, the "a" wave can be rec- ognized when it is abnormally prominent. It occurs just be- fore the first heart sound and is marked by a rapid rise and fall. Prominent "a" waves occur in patients with a sinus rhythm and tricuspid stenosis and right ventricular hyper- tension. Cannon (very large) "a" waves are seen in patients with atrial-ventricular dissociation when the right atrium contracts against a closed tricuspid valve.

It would be interesting to know if Baerman et al specifi- cally looked for cannon waves. One additional point is w o r t h no t ing : a l though a t r ia l -vent r icular d i ssoc ia t ion strongly supports ventricular tachycardia, retrograde ven- tricular-atrial conduction may occur, and the ventricular tachycardia may therefore not exhibit atrial-ventricnlar dis-

sociation. 1 Conversely atrial-ventricular dissociation can rarely occur in supraventricular tachycardia. 2

Marc Nelson, MD Department of Emergency Services Stanford University Hospital Stanford, California 1. Kirsten AD: Retrograde conduction to the atria in ventricular tachycar- dia. Circulation 1961;24:236. 2. Brunwald E: Heart Disease: A Textbook of Cardiovascular Medicine. Philadelphia, WB Saunders Co, 1984, p 637.

In ~eply: Our article was not meant to be a general review on the

differentiation of ventricular from supraventricular tachy- cardia. This is why it did not discuss the value of the jugular venous pulse. In our study, which was retrospective, reliable data on the jugular venous pulse were not available. There is no question that an irregular pattern of cannon waves indicates atrioventricular dissociation and a high likelihood that a tachycardia is ventricular in origin. 1

Fred Morady, MD University of Michigan Medical Center Ann Arbor 1. Morady F: Ventricular tachycardia, in Callaham ML {ed): Current Ther- apy in Emergency Medicine. Toronto, BC Decker, Inc, 1987, p 436-440.

Ultralight Aircraft Accidents

To the Editor: During the past ten years, ultralight aircraft, which are

essential ly motor ized versions of hang gliders, have in- creased in popularity as a recreational aircraft. The increase in the use of ultralight aircraft has led to an increase in the number of crashes. Only three cases involving injuries asso- ciated with ultralight aircraft accidents have been presented in the English literature, as indicated by Zwimpfer and Gertzbein; 1 all involve fractures of the thoraco lumbar spine. One fracture was a burst fracture of T-10 that resulted

in no neurological deficit. The second fracture was a bilat- eral facet dislocation of Tll-T12. The third case was a L-1 burst fracture with displacement of bony fragments into the spinal canal that resulted in an incomplete neurological le- sion.

We saw a 57-year-old man who presented to the emergen- cy department with neck and mid-back pain after crash landing his ultralight aircraft. Physical examination found that the patient was tender over the posterior region of C-2

16:12 December 1987 Annals of Emergency Medicine 1413/139