In Reply:--This seemingly rare but anticipated occurrence reflects Augustine Medical's intent to err on the side of patient safety. Certainly, the most serious error with the esophageal detector stylet would arise from a false-positive, indicating tracheal intubation with the stylet. Extensive research has shown that a false-positive will arise only when the stylet passes alongside an esophageal obturator airway.* Not surprisingly, this situation develops because an indwelling esophageal obturator airway opens the esophagus to air.

To minimize the incidence of a false-negative, we designed redundancy into the system by placing three holes on each side of the distal stylet. Any air leak negates a vacuum. The chance of all six holes obstructing is exceedingly small. We rejected the idea of increasing the hole size, as suggested by Haridas and Arsiradam, because it would have decreased the shaft strength, making it vulnerable to kinking.

Ultimately, verification of endotracheal intubation requires confirmation by one of the commonly accepted methods: auscultation of breath sounds or detection of carbon dioxide in the expired breath. The esophageal detection stylet merely provides evidence of correct stylet positioning at an intermediary point in the technique.

Scott D. Augustine, M.D., Chief Executive Officer.

David D. Feroe, C.R.N.A., M.S., Project Head, Augustine Medical, Inc., 10393 West 70th Street, Eden Prairie, Minnesota 55344.

(Accepted for publication April 13, 1995.)

* Kovac AC: Evaluation of the Augustine guide esophageal detection device stylet, The 5th Annual International Trauma Anesthesia and Critical Care Symposium, Amsterdam, The Netherlands, June 1992.