The use of repeat direct laryngoscopy is invasive and impractical for continuous or frequent repetitive monitoring, because it may require repeat dosing of sedatives and paralytics.

Furthermore, if direct visualization of the tube was not possible initially, this method may not be confirmatory.

End-tidal carbon dioxide detection offers the best alternative for confirmation of endotracheal tube placement.

While the qualitative end-tidal carbon dioxide method gives a good initial assessment of tube position in the patient with adequate perfusion, quantitative and continuous carbon dioxide detection is a preferred method for the continuous monitoring of proper tube location.

This technique is relatively simple and requires a capnography device connected to the ventilator. The device will record ventilatory carbon dioxide quantitatively with a waveform on a monitor.

In a patient with good circulation and perfusion, the lack of end-tidal carbon dioxide delivery should immediately alert one to the misplacement or dislodgement of the endotracheal tube.

This method has been utilized in the operating room for some time, and has made its way both to the emergency department and prehospital setting for intubation as well as procedural sedation.

Capnography is a simple method to assure continuous tube placement and approaches 100% sensitivity and specificity in the patient with spontaneous circulation.

Confirmation of endotracheal tube placement in patients with poor circulatory perfusion, particularly those in cardiac arrest or with recent return of spontaneous circulation, can be difficult.

Essentially all reported occurrences of a correctly placed endotracheal tube without detection of exhaled carbon dioxide have occurred in the setting of a low perfusion state or that of pulmonary edema.^8-13

In these patients, delivery of carbon dioxide to the lungs may be insufficient to produce reliable confirmation, and alternative confirmation techniques may be necessary.

Esophageal detector devices have limited utility as a technique for endotracheal tube position assessment. While these devices are generally easy to use, are inexpensive, and have demonstrated reasonable utility in detecting esophageal intubations, there are a number of situations in which they have not been shown to be entirely accurate.

Erroneous findings can be observed in obese patients, those with a large amount of air in the esophagus or stomach, and patients with copious pulmonary secretions.^14-16

In addition, esophageal detector devices do not allow ongoing assessment of continued proper tube location.