Verification of endotracheal tube position

Abstract

The goals of tracheal intubation are to place the tube in the trachea and to position the tube at an appropriate depth inside the trachea. Various clinical signs and technical aids are described to verify tracheal intubation and to diagnose esophageal intubation. Many of these methods fail under certain circumstances. Not all these methods can be applied in every intubation, but it is essential that the clinician involved in tracheal intubation have the necessary airway management skills, perform these tests accurately, and interpret the results correctly. Prioritization of these tests depends on many factors, including familiarity, availability of monitors, and the location of intubation. Viewing the tube passing between the cords during direct laryngoscopy and visualization of the tracheal rings and carinae with a fiberoptic scope after intubation are the only fullproof methods of confirming tracheal intubation. In the nonarrested patient, carbon dioxide monitoring quickly can differentiate tracheal from esophageal intubation. In the arrested patient, however, carbon dioxide monitoring can be unreliable, although it can be useful as a prognostic indicator of the efficacy of resuscitation. Devices such as [figure: see text] the self-inflating bulb and esophageal detector device may be more useful in patients with cardiac arrest, but they also can yield false results. Placing the distal tip of the tube in the middle of the trachea can be accomplished by positioning the upper end of the cuff 2 cm below the cords during direct laryngoscopy or by placing the distal tip of the tube 4 cm above the carinae with the aid of a fiberoptic scope. The position of the tube always should be verified by clinical assessment (e.g., auscultation). If direct visualization cannot be done, referencing the marks on the tube, transillumination techniques, or cuff maneuvers can be helpful. In the emergency and critical care settings, a chest radiograph easily can detect malpositioned tracheal tubes that may not be detected by routine clinical assessment. Other techniques (e.g., use of fiberoptic scopes, cuff maneuvers, transillumination) can decrease the need for frequent chest radiographs. Based on available information, two algorithms are proposed: one for emergency intubation (Fig. 9) and the other for verification of tracheal tube position in elective intubation (Fig. 10). These algorithms are designed [figure: see text] to assist the clinician and should not be substituted for clinical judgment. Under no circumstances should clinical signs be ignored in the presence of conflicting information from monitors and technical aids.