EFFICACY OF THE SELF-INFLATING BULB IN DETECTING ESOPHAGEAL INTUBATION - DOES THE PRESENCE OF A NASOGASTRIC TUBE OR CUFF DEFLATION MAKE A DIFFERENCE

Background: The principle underlying the use of the self-inflating bul b in differentiating esophageal from tracheal intubation is that the t rachea is held open by rigid cartilaginous rings, whereas the esophagu s collapses when a negative pressure is applied to its lumen. This inv estigation was designed to test the efficacy of the bulb in detecting esophageal intubation in the presence of a nasogastric tube and after tracheal tube cuff deflation. Methods: In anesthetized patients, the t rachea and esophagus were intubated with identical tubes. The efficacy of the bulb was tested after a nasogastric tube was placed (group 1, n=70) and after cuff deflation (group 2, n=60) by a second anesthesiol ogist. Results: In patients with nasogastric tubes (group 1), the anes thesiologists reported no reinflation of the compressed bulbs connecte d to tubes placed in the esophagus and immediate reinflation when conn ected to tracheally placed tubes in every case. In group 2, the determ ination of tube placement was correct in every case after cuff deflati on. Mean (+/-SEM) negative pressures generated when compressed bulbs w ere connected to esophageally placed tubes were 57.8+/-0.48 mmHg (grou p 1) and 55.3+/-0.52 mmHg (group 2) and remained unchanged after the i ntroduction of nasogastric tubes or after cuff deflation. Conclusions: These results confirm that a nasogastric tube or cuff deflation does not interfere with the reliability of the self-inflating bulb in detec ting esophageal intubation and thus does not contribute to false posit ive results. Confirmation of tracheal tube placement by this simple me thod makes it ideal for use with other recognized methods both in and outside the operating rooms and enables physicians and emergency perso nnel to proceed with other resuscitative measures.