Evaluation of an electronic esophageal detector device in patients with morbid obesity and pulmonary failure

Undetected esophageal intubation can result in permanent injury or death. Clinical confirmation of tube location may be misleading. Adjunctive methods should be used to supplement clinical judgment. Unfortunately, end-tidal carbon dioxide may misidentify properly placed tracheal tubes in low perfusion situations, while esophageal detector devices (EDDs) may misidentify properly placed tracheal tubes in situations where little airway dead space exists (morbid obesity, pulmonary failure). This study evaluated a modified EDD (the electronic esophageal detector device, or EEDD) designed to eliminate the problem of misidentified tracheal intubations.

Intubated morbidly obese or pulmonary failure patients were eligible for study entry. All endotracheal tubes (ETTs) were confirmed to be tracheal by waveform capnography and clinical judgment prior to study entry. Following consent, all patients were attached to the EEDD and a "measurement" was made to determine the "location" of their ETTs. Probability of misidentifying a tracheal intubation in these high-risk populations was calculated using a log-normal distribution method.

Twenty-seven morbidly obese patients and 37 pulmonary failure patients were entered. The EEDD correctly identified all tracheal intubations in these patients, giving a false-negative rate of zero. The probability of misidentifying a tracheal intubation in the combined group was 0.06%.

This study demonstrates that the EEDD reliably identifies tracheal intubations in situations where standard EDDs may fail. However, future studies must determine the reliability of this device for identification of esophageal intubations and the reliability of this device in the less controlled emergency department and prehospital settings.