The esophageal obturator airway (EOA) was introduced for clinical use in 1973. There have been few controlled studies on its effectiveness or safety; those published had differing results—one showed no clinically significant difference in Pao 2 and Paco 2 between EOA and tracheal tube, while two others reported slightly increased Paco2. Subsequent modifications include the esophageal pharyngeal airway, esophageal gastric tube airway, and Vermont, or Pilcher, model. The EOA is indicated in the apneic or deeply unconscious patient. It is contra-indicated in the conscious or semiconscious patient, in children, for more than 1-2 hours, and in known cases of esophageal trauma or pathology. The most commonly reported hazard is esophageal perforation; others include tracheal intubation (which is actually the most common hazard), failure to seal mask, failure to pass tube, incorrect assembly of mask and tube, the tube's becoming an intragastric foreign body, and obstruction to intubation. While the tube is not the hazard-free device it was once thought to be, it has a place in emergency airway management in preventing insufflation of air into the stomach as well as aspiration of gastric contents.
Fluck et al. (Mon,) studied this question.