Anesth Analg 2004;99:1269-1270
© 2004 International Anesthesia Research Society
doi: 10.1213/01.ANE.0000133955.92363.B1
LETTERS TO THE EDITOR
The Eschmann Tracheal Tube Introducer Is Not an Airway Exchange Device
M. El-Orbany, MD, and
M. R. Salem, MD
Department of Anesthesiology, Advocate Illinois Masonic Medical Center, Chicago, IL
To the Editor:
We read with interest the article by Nekhendzy and Simmonds (1). Although the authors opted to use the Eschmann introducer (gum elastic bougie) and declined the use of the Cook Airway Exchange Catheter (CAEC), we think that the latter was a better choice for a safe and successful exchange. The authors’ argument was that they did not choose the CAEC because if reintubation fails, adequate oxygenation will be unlikely through the catheter. They did not consider, however, the consequences of a failed reintubation if the introducer is used. Oxygen insufflation through the CAEC can deliver a stream of oxygen to the alveoli. Although this might not be enough for adequate oxygenation, it can still be a temporary protective measure until a successful attempt at reintubation is achieved. This advantage is nonexistent if failure to thread the tube over the introducer is encountered. Their second reason for preferring to use the Eschmann introducer is its stiffness. Although the introducer is stiffer than the CAEC, the latter is not excessively flexible as the authors described and has been successfully used for airway exchange during similar situations (2). The authors concern that the catheter may produce lung perforation if it is too deeply placed also applies if the introducer is used and the "hold up" sign is sought. Deep placement and trauma, however, is more likely to be encountered with the introducer since the catheter has 1-cm markings and no hold up is sought with its use, allowing better control of the insertion depth, whereas the introducer is marked every 10 cm and the hold up sign is frequently sought.
Viswanathan et al. mentioned two cases of right-sided pneumothorax and one case of mediastinal emphysema that developed shortly after the use of an Eschmann introducer as an airway exchange device (3) Although the authors described in detail the potential complications when a CAEC is used, they never mentioned the reported complications associated with the use of the introducer, whether due to trauma (4,5), tip detachment (6), or outer layer fracture (7). Finally, the use of a CAEC could have allowed safe withdrawal of the bronchoscope without the need to use an extension suction catheter, since it is much longer than the introducer (83 vs 60 cm).
The intended use of the Eschmann tracheal tube introducer is to give directional control when a difficult laryngeal exposure is encountered, and it functions well when used as intended. It is not designed or intended to be used, however, as an airway exchange device, since other devices that serve this purpose are available. Although the authors were successful in managing the airway with the use of an Eschmann introducer, its use for this purpose is discouraged by the manufacturer as well as by many others (3,8). We believe that the Cook Airway Exchange Catheter could have allowed a safe, smooth, and successful exchange in this case and should be seriously considered when similar cases are encountered in the future.
References
- Nekhendzy V, Simmonds PK. Rigid bronchoscope-assisted endotracheal intubation: yet another use of the gum elastic bougie. Anesth Analg 2004; 98: 545–7.[Abstract/Free Full Text]
- Lambotte P, Menu H, Guermouche T, et al. Intraoperative exchange of the endotracheal tube using the Cook C-CAE airway exchange catheter. Ann Fr Anesth Reanim 1998; 17: 1235–8.[Medline]
- Viswanathan S, Campbell C, Wood DG, et al. The Eschmann tracheal tube introducer (gum elastic bougie) Anesthesiol Rev 1992; 19: 29–34.[Medline]
- Kadry M, Popat M. Pharyngeal wall perforation: an unusual complication of blind intubation with a gum elastic bougie. Anaesthesia 1999; 54: 404–5.[Medline]
- Prabhu A, Pradhan P, Sanaka R, Bilolikar A. Bougie trauma: it is still possible. Anaesthesia 2003; 58: 811–3.
- Gardner M, Janokwski S. Detachment of the tip of a gum-elastic bougie. Anaesthesia 2002; 57: 88–9.
- Robbins PM. Critical incident with gum elastic bougie. Anaeth Intensive Care 1995; 23: 654.
- Salem MR, Baraka A. Confirmation of tracheal intubation. In: Benumof JL, ed. Airway management: principles and practice. St. Louis: Mosby-Year Book, 1996: 531–60.
Response
Vladimir Nekhendzy, MD, and
Paul Simmonds, MD
Department of Anesthesia, Stanford University Medical Center, Stanford University, Stanford, CA, nek@stanford.edu
Department of Anesthesia, John Hopkins Hospital, John Hopkins University, Baltimore, MD
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.
References
- Nekhendzy V, Simmonds PK. Rigid bronchoscope-assisted endotracheal intubation: yet another use of the gum elastic bougie. Anesth Analg 2004; 98: 545–7.
- Cooper RM. Extubation and changing endotracheal tubes. In: Benumof JL, ed. Airway management: principles and practice. St. Louis: Mosby, 1996: 864–85.
- Slutsky AS, Watson J, Leith DE, Brown R. Tracheal insufflation of O2 (TRIO) at low flow rates sustains life for several hours. Anesthesiology 1985; 63: 278–86.[Web of Science][Medline]
- Mackenzie CF, Barnas G, Nesbitt S. Tracheal insufflation of oxygen at low flow: capabilities and limitations. Anesth Analg 1990; 71: 684–90.[Abstract/Free Full Text]
- Lumb AB. Nunn’s applied respiratory physiology. 5th ed. Oxford: Butterworth Heinemann, 1999.
- Stone DJ, Bogdonoff DL. Airway considerations in the management of patients requiring long-term endotracheal intubation. Anesth Analg 1992; 74: 276–87.[Medline]
- Viswanathan S, Campbell C, Wood DG, et al. The Eschmann tracheal tube introducer (gum elastic bougie). Anesthesiol Rev 1992; 19: 29–34.
- Benumof JL. Airway exchange catheters for safe extubation: the clinical and scientific details that make the concept work. Chest 1997; 111: 1483–6.[Free Full Text]
- Sellers WF. Gum elastic bougies. Anaesthesia 2002; 57: 289.
- Hodzovic I, Latto IP, Henderson JJ. Bougie trauma: what trauma? Anaesthesia 2003; 58: 192–3.[Web of Science][Medline]
- Desai SP, Fengl V. A safe technique for changing endotracheal tubes. Anesthesiology 1980; 53: 267.[Medline]
- Latto IP, Stacey M, Mecklenburgh J, Vaughan RS. Survey of the use of the gum elastic bougie in clinical practice. Anaesthesia 2002; 57: 379–84.[Web of Science][Medline]
- Cook TM. A new practical classification of laryngeal view. Anaesthesia 2000; 55: 274–9.[Web of Science][Medline]
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