The Eschmann Tracheal Tube Introducer Is Not an Airway Exchange Device

Abstract

In Response: We thank Drs. El-Orbany and Salem for their interest in our report (1) and appreciate this opportunity to respond to their comments. When devising an airway exchange strategy, it is essential to “…establish that the potential benefits [of the airway exchange technique] exceed the probable risks” (2). We believe that the benefit/risk ratio was not in favor of the CAEC in this particular patient with severely compromised upper and lower airway. The potential benefits of the CAEC as an intubation guide include the opportunity to administer oxygen by jet ventilation or tracheal insufflation. Jet ventilation was contraindicated in our patient due to the severe upper airway edema and potential for gas entrapment. The ability of tracheal insufflation of oxygen (TRIO) to sustain adequate oxygenation during periods of apnea in subjects with normal lungs is well recognized (3). However, the efficacy of this technique cannot be extrapolated to situations when a known ventilation-perfusion mismatch exists (4). Although debating the use of TRIO as a “temporary protective measure” against rapidly ensuing hypoxemia in an apneic patient with a nearly 30% preexisting shunt (5) can be an intellectually stimulating exercise in pulmonary physiology, we believe that its effectiveness would have been dubious at best. Therefore, given the inability to effectively utilize the merits of the CAEC as an oxygen source during the reintubation attempt(s), and the absent formal studies documenting the reliability of the CAEC as an intubation guide in patients with abnormal airway, we turned our attention to the GEB. The probable risks of either airway exchange device in this patient included accidental dislodgement of the device out of the trachea during the rigid bronchoscope withdrawal and trauma to the lung. By advocating the use of the CAEC to observe the centimeter markings and therefore avoiding deep subcarinal placement, Drs. El-Orbany and Salem miss the most important point: deep placement of either device was essential to the success of the airway exchange technique in this patient. First, monitoring the centimeter markings on the CAEC would not be possible since all of the markings would be embedded inside the 40 cm-long lumen of the bronchoscope. Second, once the bronchoscope withdrawal is initiated, mapping out the distance to the carina on the introducer becomes impossible since the bronchoscope needs to be withdrawn at least 22–30 cm to the teeth level (6) before the introducer can be grasped and stabilized inside the patient’s mouth. Therefore, a deep subcarinal placement of either device was required to prevent the distal end of the introducer from accidentally springing backwards out of the trachea into the posterior pharynx. Anchoring the distal end of the GEB in the small bronchus (the distal hold up sign) assured the necessary depth of the introducer placement and provided the required stability of the introducer during the bronchoscope withdrawal. We disagree with Drs. El-Orbany and Salem’s statement that a deep placement of the GEB carries a higher risk for lung perforation as compared with the CAEC. Although the incidence of the tracheobronchial tree perforation may be underreported for both devices (7,8), the presence of the round angulated tip prevents the GEB from reaching a very small bronchus (9,10): a feature that is nonexistent with the CAEC. While Drs. El-Orbany and Salem are correct in stating that the GEB is not intended for use as an airway exchange device, its safe use for this purpose has been documented in over 50 patients (11). We would also like to mention that the intended use of the CAEC is for exchanging endotracheal tubes (mostly in the critical care setting) and not for facilitating an airway exchange in patients with an abnormal airway. Finally, we felt that directing the angulated bougie tip to the right on exit from the bronchoscope reasonably well guaranteed avoidance of further possible trauma and renewed bleeding from the surgically manipulated left main bronchus. The use of all airway devices carries a certain risk of associated complications. We believe that decision-making in the difficult airway management should be guided by the specific clinical situation and the clinical data regarding the effectiveness of the applicable airway techniques. As opposed to the GEB (12,13), the reliability of the CAEC as an intubation guide in patients with abnormal airway has not been scientifically substantiated. Formal studies comparing different brands of the AECs as guides for tracheal intubation in these patients are needed to establish the aforementioned reliability and success rates of these versatile devices. Vladimir Nekhendzy, MD Department of Anesthesia Stanford University Medical Center Stanford University Stanford, CA [email protected] Paul Simmonds, MD Department of Anesthesia John Hopkins Hospital John Hopkins University Baltimore, MD