Reporte de Caso

Nasotracheal Intubation Guided with the Bonfils Retromolar Fiberscope Introduced Into the Oral Cavity

Fritz E. Gempeler R.*, Y. Lorena Díaz B.**

* Profesor Asociado, Facultad de Medicina, Pontificia Universidad Javeriana, Anestesiólogo Hospital Universitario, San Ignacio, Bogotá, Colombia, gempeler@javeriana.edu.co
** Estudiante de postgrado Anestesiología, Pontificia Universidad Javeriana, Hospital Universitario de San Ignacio, Bogotá, Colombia.

Recibido: agosto 9 de 2010. Enviado para modificaciones: noviembre 10 de 2010. Aceptado: noviembre 19 de 2010.

SUMMARY

Introduction. Among the various devices available for airway management, one of them stands out: the retromolar Bonfils fiberscope. The Bonfils has proven to be effective and easy to use, besides being non-traumatic and useful in patients in whom direct laryngoscopy is unsuccessful, in patients with cervical trauma, limitation of mouth opening and intubation with the patient awake.

Methodology. This case report describes the oral Bonfils-guided nasotracheal intubation technique, successfully accomplished in 19 patients.

Conclusions. The experience obtained with this device in over 300 oral intubations leads us to believe that the Bonfils retromolar fiberscope is ideal and superior to the conventional laryngoscope for the routine management of the airway.

INTRODUCTION

The Bonfils retromolar fiberscope, usually referred to as the "Bonfils", is one of the devices developed for managing the difficult airway (1). The Bonfils is a fiber-optic stylet contained within a 40 cm long semi-rigid steel tube, with an outer diameter of 5 mm and a 40-degree distal end (Figure 1). Its proximal end contains a lens and a light source connection. It was initially used for the management of the difficult airway around the 90's and today is a very useful device for the management of the unexpected difficult airway (2-4).

Studies done with inexperienced medics and paramedics in the management of the device, adequate effectiveness of a first-attempt intubation is achieved after 25 cases of Bonfils intubation (2,5).

When individuals experienced in the use of the device do the maneuver, the first-attempt intubation effectiveness is 96.8 % for a normal airway and 92.5 % for the difficult airway (3,6). Due to its easy management, its short learning curve, reduced intubation time and lower probability of dental and soft tissue trauma versus the traditional laryngoscope, the Bonfils is also used for routine endotracheal intubation.

There are several reports on the use of the Bonfils for the intubation of patients with a normal airway under general anesthesia, as well as patients with unexpected or suspect difficult airway, including those who have failed intubation under direct laryngoscopy and patients with limited neck mobility and/or cervical trauma, intubation while the patient is awake and as a tool for percutaneous tracheostomy (3,7-9).

Series of cases and meta-analysis can be found in the literature regarding the use of the Bonfils in different clinical circumstances; however, there are no reports described on the oral Bonfils-guided nasotracheal intubation.

After acquiring experience in the management of the Bonfils fiberscope for intubating patients with normal or difficult airway, with over 300 successful oral intubations, we decided to use the device in other applications such as nasotracheal intubation, particularly in difficult airway patients, introducing the Bonfils through the oral cavity to guide the intubation. Likewise, we have done sequential rapid induction intubations and Bonfils-guided intubation of infants and neonates for orotracheal intubation without using the traditional laryngoscope.

METHODOLOGY

Following is a description of the technique used in 19 cases of nasotracheal intubation guided under direct vision with the Bonfils retromolar fiberscope in adult patients; the procedure was performed by people trained in the use of the device.

The patient arrives at the OR and is placed in supine decubitus position with the head in neutral position. Conventional monitoring is done, facemask pre-oxygenation at a rate of 4 l/min, intravenous induction of the general anesthesia, administration of intra-nasal 0.025 oximetazoline into the nasal fossa selected for intubation that has been previously assessed with the patient awake and lubricated with gel lidocaine using a cotton swab.

With the patient under general anesthesia and under the appropriate level of anesthesia, relaxed for any intubation procedure, the tube is then instroduced into the selected and prepared nasal cavity, advancing the tube down to the oropharynx. Then, the assistant performs an upward mandibular traction and the Bonfils retromolar fiberscope is inserted through the right lip commissure for a "retromolar bon-filoscopy" (Figure 2) until the epiglottis and the vocal cords are identified. Then the Bonfils is slightly removed to have a panoramic view of the oropharynx and identify the tracheal tube (Figure 3). The person doing the intubation manouvers the Bonfils and the endotracheal tube, while the assistant keeps the upward mandibular traction to improve the visibility of the manouver (Figure 4).

The tube is advanced up to the field of observation of the Bonfils and immediately the tube is guided up to the trachea under direct vision with the Bonfils, watching how the tube passes through the vocal cords (Figure 5).

The Bonfils fiberscope is then finally removed, the tubes position is checked with auscultation and capnography and the anesthetic and surgical procedure then proceeds as planned.

In the 19 cases (100 %) the Bonfils-guided nasotracheal intubation was successful; in 12 of the 19 patients (63.1 %) the intubation was performed as previously described.

When advancing the nasotracheal tube in 5 of the 19 patients (26.31 %) it collided against the arytenoid cartilages and a Burp maneuver (mild external compression of the thyroid cartilage towards the back) was required in order to lower the glottis slightly and allow for the passage of the nasotracheal tube.

In 2 of the 19 patients (10.5 2 °%) the nasotracheal tube was directed straight into the esophagus and it was impossible to introduce it through the glottis, despite a Burp maneuver. Thus, it was necessary to pass the Bonfils retromolar fiberscope under the tube (Figure 6) and simultaneously advance the tube and the Bonfils, localize the glottis, take the tube down to the glottis and advance it, watching the passage of the tube through the vocal cords (Figure 7). In this maneuver you can see the tube in the upper part of the Bonfils (Figure 8).

DISCUSSION

As experts in the management of the airway, anesthesiologists avail themselves of the necessary tools and skills for managing the airway under different circumstances.

There are various devices available for the management of the airway that are used according to the manufacturer's indications; however, once we become skillful in managing these instruments, we may then use them in different ways for the benefit of our patients.

The Bonfils retromolar fiberscope is an instrument originally developed for the difficult airway (5,6) and it has been proven to be a non-traumatic and useful device in patients who have failed direct laryngoscopy, in patients with cervical trauma, patients with limited mouth opening and intubation of patients who are awake (7,10-12). Like any other device for the management of the difficult airway, the Bonfils must initially be used in normal airway patients until adequate experience is acquired.

Some of the Bonfils advantages are a short learning curve, minimal intubation time, less airway stimulus and lower incidence of iatro-genic events. Its rigid structure facilitates its management inside the patient's mouth and airway. The Bonfils distal angulation provides easy passage through the posterior aspect of the epiglottis; moreover, it has been found that the intubation can be accomplished in a shorter period of time, as compared to other difficult airway devices.

Because of all of these reasons, the Bonfils retromolar fiberscope is ideal and superior to the conventional laryngoscope for the routine management of the airway, even in patients subject to a rapid induction sequence.

Learning to manage the Bonfils retromolar fiberscope and acquiring the necessary skills offers the opportunity to use the device for different applications such as this current report of a Bonfils-guided nasotracheal intubation or the placement of orotracheal tubes in pediatric patients and neonates and its use as an instrument to visualize the larynx, its structures and any potential pathologies. So why can't we speak about "Bonfiloscopy"? There are indeed many other uses to be explored.

REFERENCES

1. American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Practice guidelines for management of the difficult airway: an updated report by the American society of anesthesiologists task force on management of the difficult airway. Anesthesiology 2003;98:1269-77.

2. Rudolph C, Schlender M. Clinical experiences with fiber optic intubation with the Bonfils intubation fiberscope. Anaesthesiol Reanim 1996;21:127-30.

3. Halligan M, Charters P. A clinical evaluation of the Bonfils intubation fibrescope. Anaesthesia 2003;58:1087-91.

4. Bein B, Worthmann F, Scholz J, Brinkmann F, Tonner PH, Steinfath M, Dörges V. A comparison of the intubating laryngeal mask airway and the Bonfils intubation fibrescope in patients with predicted difficult airways. Anaesthesia 2004;59: 668-74.

5. Liem EB, Bjoraker DG, Gravenstein D. New options for airway management: intubating fibreoptic stylets. Br J Anaesth 2003;91:408-18.

6. Hagberg CA. Special devices and techniques. Anesthesiol Clin North America 2002;20:907-3.

7. Grant S.A, Breslin D.S, MacLeod D.V, Gleason D, Martin G. J Dexmedetomidine Infusion for Sedation During Fiberoptic Intubation: A Report of Three Cases Clin Anesth, 16:124-126, 2004.

8. Buehner U, Oram J, Elliot S, Mallick A, Bodenham A. Bonfils semirigid endoscope for guidance during percutaneous tracheostomy. Anaesthesia 2006;61: 665-70.

9. Abramson SI, Holmes AA, Hagberg CA, Awake Insertion of the Bonfils Retromolar Intubation Fiberscope^TM in Five Patients with Anticipated Difficult Airways Anesth Analg 2008;106:1215-7.

10. Gempeler F. Devis A. Pedraza P. Intubación con paciente desierto con fibroscopio retromolar de Bonfils, bajo sedación con Dexmedetomidina. Reporte de 7 casos. Revista Colombiana de Anestesiología y Reanimación 2009 Vol 37 N° 1 pag 49-56.

11. Wahlen BM, Gercek E. Three-dimensional cervical spine movement during intubation using the Macintosh and Bullard laryngoscopes, the Bonfils fibrescope and the intubating laryngeal mask airway. Eur J Anaesthesiol 2004;21:907-13.

12. Rudolph C, Schneider JP, Wallenborn, Schaffranietz L. Movement of the upper cervical spine during laryngoscopy: a comparison of the Bonfils intubation fibrescope and the Macintosh laryngoscope. Anaesthesia 2005;60:668-72.

Conflicto de intereses: ninguno declarado