The EID® overcomes many of the shortcomings of ETCO2, yet is very reliable, as demonstrated in over 30 research articles. The device relies on anatomical differences between the trachea and the esophagus to function. By applying negative pressure to the endotracheal tube, the EID takes advantage of these anatomical differences. The rigid trachea remains open, allowing free aspiration of air into the EID, whereas the fibromuscular esophagus collapses around the endotracheal tube and thus prevents aspiration of air. The EID does not depend on physiologic parameters such as CO2 production. It remains accurate, even on patients suffering cardiac arrest in which CO2 production may not be detectable.
There are several advantages to EID There are several advantages to EID technology over ETCO2 technology. The first is the continued accuracy in the cardiac arrest patient. In the prehospital setting, this accounts for a large percentage of intubations. A second advantage is the immediate answer. The EID gives a ‘yes’ or ‘no’ answer in less than five seconds; ETCO2 takes six to seven breaths (approximately 30 seconds) to register reliably. If the endotracheal tube is accidentally placed into the esophagus, this delay in information and continued ventilation of the esophagus often leads to gastric (stomach) distention and resultant vomiting with aspiration of stomach contents into the lungs - a severe complication. Other advantages are the low cost, durability, long shelf life, and simplicity.