We read with great interest the comments Dr. Nadarajan made regarding our study comparing two techniques for retrograde orotracheal intubation,1and we thank him for the consideration he gave to our work.1 

Regarding the causes of the failure, we agree that, if the endotracheal tube has not been positioned beneath the vocal cords, the catheter may be difficult to insert or placed in a wrong position, and tracheal intubation will fail. In our study, most of the failures were due to a supraglottic placement of the endotracheal tube as a consequence of a wrong position of the catheter. The size of endotracheal tube was adapted to the patient’s morphology to allow its easy insertion into the trachea, as mentioned in the guidelines related to the airway management edited by the French Society of Anesthesia and Intensive Care.2The rotation of the endotracheal tube was also used to help the right positioning of the bevel and facilitate its passage between the vocal cords. Also, as discussed in the article,1we believe that, in alive patients, the analysis of the expired gas at the extremity of the catheter may be of great importance to confirm the correct position of the catheter before removing the guide wire.

The literature regarding the retrograde tracheal intubation is sparse, and to our knowledge, there is no study comparing cricoid and subcricoid approaches in terms of complications, morbidity, and mortality. The subcricoid approach, enhancing the distance between the vocal cords and the site of the puncture, has been proposed to decrease the incidence of accidental extubation during retrograde tracheal intubation.3If the incidence of failure is decreased, the safety of this approach remains questionable. Regarding the cricoid approach, some of the complications have been reported during minitracheostomy,4,5and one can suppose that an incision may be more deleterious than a puncture with a needle and the insertion of a guide wire. It is difficult to conclude that the subcricoid approach should be preferred to the cricoid approach for retrograde tracheal intubation, and there are some good reasons to recommend the cricoid approach.6Because of its superficial localization, the cricothyroid membrane is easy to localize, the risk of accidental puncture of the thyroid gland is very low, and finally, the cricoid approach is easy to learn because the puncture of the cricothyroid membrane is used for other purposes, such as cricoid local anesthesia.

*Hopital General, Centre Hospitalier Universitaire de Dijon, Dijon, France. francois.lenfant@chu-dijon.fr

Lenfant F, Benkhadra M, Trouilloud P, Freysz M: Comparison of two techniques for retrograde tracheal intubation in human fresh cadavers. Anesthesiology 2006; 104:48–51
Francon D, Estebe JP, Ecoffey C: De quel matériel doit-on disposer pour la prise en charge des voies aériennes et quelles sont les alternatives à la sonde d’intubation (masque facial, masque laryngé et tube laryngé)? Quelle maintenance pour ce matériel? Ann Fr Anesth Reanim 2003; 22:28s–40s
Shantha TR: Retrograde intubation using the subcricoid region. Br J Anaesth 1992; 68:109–12
van Heurn LW, van Geffen GJ, Brink PR: Percutaneous subcricoid minitracheostomy: Report of 50 procedures. Ann Thorac Surg 1995; 59:707–9
Dover K, Howdieshell TR, Colborn GL: The dimensions and vascular anatomy of the cricothyroid membrane: Relevance to emergent surgical airway access. Clin Anat 1996; 9:291–5
Boisson-Bertrand D, Bourgain JL, Camboulives J, Crinquette V, Cros AM, Dubreuil M, Eurin B, Haberer JP, Pottecher T, Thorin D, Ravussin P, Riou B: Intubation difficile: Société française d’anesthésie et de réanimation Expertise collective. Ann Fr Anesth Reanim 1996; 15:207–14