Retrograde Intubation Over a Flexible Fiber-Optic Bronchoscope

Abstract

Traditional retrograde intubation consists of tracheal intubation performed over a guide wire inserted into the trachea inferior to the vocal cords and then passed transorally or transnasally. This intubation technique is reserved for patients with a difficult airway when other methods such as blind nasal intubation or video laryngoscopy fail. A guide wire passed blindly in a retrograde fashion, however, is not without its own constraints. This case report presents the anesthetic management of a 23-year-old Duchenne muscular dystrophy patient with substantial scarring from a previous tracheostomy stoma and limited mouth opening. The patient underwent a retrograde fiber-optic transnasal intubation without the use of a guide wire for a tracheostomy revision procedure, followed by a second tracheostomy revision and retrograde fiber-optic transoral intubation 7.5 months later. This report demonstrates a novel technique for intubating patients with difficult airways. The use of a flexible fiber-optic bronchoscope for a retrograde intubation mitigates complications that can arise using traditional retrograde intubation over a guide wire and increases the likelihood of successful intubation.

Retrograde endotracheal intubation is a technique typically used in cases of difficult airway management. This method was first described by Butler and Cirillo¹ as an alternative to difficult intubation or a tracheostomy within the surgical field. The technique involves puncturing the cricothyroid membrane with a needle to gain access to the trachea, passing a guide wire in a cephalad direction through the airway, and then passing the endotracheal tube (ETT) into the trachea over the guide wire.^1,2 There have been a number of reported indications for retrograde intubation, including failure to intubate using other methods, inability to visualize the vocal cords, supraglottic and subglottic stenosis, and airway obstruction.^3,4

To our knowledge, there are no reports of a flexible fiber-optic bronchoscope (FFB) being passed through an existing tracheostomy site and used for retrograde intubation. When this technique (ie, a flexible fiber-optic scope) is used in lieu of passing a guide wire through the tracheostomy site, the airway can be actively visualized throughout the intubation procedure. This report describes a series of cases involving retrograde intubations performed using an FFB for a patient with Duchenne muscular dystrophy. Because patients with this disease often have macroglossia along with limited neck and mandibular mobility, airway access can often be difficult to obtain.⁵ By performing retrograde intubation using an FFB, we were able to effectively gain access to and safely secure this patient's airway via the transnasal and transoral routes.

CASE PRESENTATION

A 23-year-old man with a history of Duchenne muscular dystrophy, cardiomyopathy, and ventilator dependence with a permanent tracheostomy complicated by recurrent excessive secretions, infections, and substantial granulation tissue formation presented for stoma revision and removal of granulation tissue. At baseline, the patient was awake, following commands, and able to communicate via writing and head nod. His airway exam was significant for Mallampati class IV, limited mouth opening (<1 cm), retrognathia, and limited range of motion of his neck. Upon auscultation his lungs were clear bilaterally, albeit with limited air movement. Given the patient's significantly limited mouth opening, we elected to perform a transnasal intubation.

Prior to induction, precautions were taken to avoid volatile agents, the patient was given glycopyrrolate 0.2 mg intravenously to minimize secretions, and preoxygenation occurred via his existing tracheostomy. The patient then underwent a slow, controlled intravenous induction with midazolam 2 mg, fentanyl 50 mcg, and propofol 100 mg while on 100% oxygen, and general anesthesia was maintained with a propofol continuous infusion of 80 mcg/kg/min. The tracheostomy tube was removed, and an Aintree intubation catheter (Cook Medical) was placed in the mouth and advanced into the oropharynx to serve as a visual aid and potentially a secondary rescue device (Figure 1). An FFB (855 mm long; LF-GP; Olympus Medical) was inserted through the tracheostomy stoma into the trachea (Figure 2) and advanced cephalad into the nasopharynx until the nasal turbinates were visualized. The scope was then advanced through the nasal cavity, delivered out of the right nostril (Figure 3), and secured. A warmed and lubricated 6.0 nasal Ring-Adair-Elwyn (RAE) tube was placed over the distal end of the scope and advanced caudally without resistance until the ETT was visualized in the stoma. The FFB was then removed, and the ETT was positioned appropriately for the stoma revision. The total time from insertion of the bronchoscope to final positioning of the ETT was less than 5 minutes. Proper ETT placement was confirmed via continuous end-tidal carbon dioxide, bilateral breath sounds, and bilateral chest rise. The procedure was well tolerated, and the patient remained hemodynamically stable throughout.

Figure 1. .

Intraoral placement of Aintree intubation catheter. An Aintree intubation catheter (Cook Medical) was advanced intraorally into the posterior oropharynx to serve as a visual aid and a potential secondary rescue device.

Figure 2. .

Insertion of the scope into the stoma. A flexible fiber-optic bronchoscope (855 mm long, LF-GP, Olympus Medical) was inserted in the patient's tracheostomy stoma and advanced cephalad.

Figure 3. .

Successful retrograde advancement of the scope. The scope was successfully advanced through the stoma out the right nares for use as a nasal intubation guide.

The previously discussed patient returned to the OR 7.5 months after his initial tracheostomy revision for a tracheoplasty with partial closure of the stoma. In the interim, the patient had worsening secretions, recurrent infections including Pseudomonas tracheitis and pneumonia, and an inability to talk due to leakage around the tracheostomy site. The patient's airway examination remained unchanged from his prior anesthetic.

As before, preoxygenation took place via his existing tracheostomy tube with 100% oxygen. General anesthesia was again induced with midazolam 2 mg, fentanyl 100 mcg, and propofol 100 mg and maintained with an infusion of propofol 100 mcg/kg/min. After induction, the tracheostomy tube was removed and the FFB advanced through the stoma, directed cephalad along the trachea. At the same time, a size 3 Macintosh blade was inserted into the mouth, producing a Cormack-Lehane grade 4 view during direct laryngoscopy. Although a transnasal intubation was electively performed during the first anesthetic because of the patient's limited mouth opening, we elected to perform a transoral intubation during the second anesthetic given the absence of tracheal supraglottic or subglottic stenosis and the ability to perform direct laryngoscopy. Once the end of the scope was visualized in the mouth and secured, a 6.0 cuffed standard ETT was inserted over the scope and then advanced towards the stoma. Upon visualization of the ETT in the stoma, the scope was removed, and the tube was placed appropriately for the surgical procedure. The patient tolerated the procedure well and was extubated without incident.

DISCUSSION

First introduced in 1960, retrograde intubation has proven useful for challenging airways, typically after failing blind nasal intubation or video laryngoscopy.¹ Retrograde intubations have been an integral part of the anesthetic management of cases involving trismus, limited mouth and jaw mobility, bone and joint disorders impacting the airway, presence of blood and secretions in the airway, airway obstruction or tumors, or failed intubation using other techniques.² Although there have been prior reports on the utility of maintaining fiber-optic visualization in the mouth during traditional retrograde intubation over a guide wire,⁶ we believe this to be the first report of 2 retrograde intubations performed over an FFB.

Barriot and Riou⁷ reported that physicians trained in retrograde intubation can perform it in under 5 minutes, commenting that it was an easy technique to learn. Hatton et al⁸ reported that after training on embalmed cadavers, the proportion of residents who responded they would use retrograde intubation increased from 6% to 67% and those who responded they could correctly perform the technique increased from 28% to 83%.

Common complications when using this procedure include difficulty passing the ETT through the vocal cords, difficulty with spatial orientation or an inability to locate appropriate anatomical structures, and prolonged procedure time.^3,4 Passage of the guide wire in a blind retrograde fashion poses its own constraints. The guide wire can coil or break, damage airway structures, and, in rare cases, cause pneumomediastinum.⁹

Passage of an FFB in lieu of a guide wire can help to mitigate many of the complications associated with the traditional guide-wire method. However, some possible limitations of this technique are that it requires availability of fiber-optic equipment and a skilled operator who can successfully navigate the airway anatomy in a potentially unfamiliar way. The FFB must also be long enough to transverse the length of airway (ie, from the stoma to the mouth or nares). The scope used in this report, produced by Olympus Medical, was 855 mm long. In addition, retrograde fiber-optic intubation may require a larger opening into the trachea than when using a guide wire. For our patient, during both of his intubations, we were able to maintain adequate visualization by avoiding secretions in the upper airway upon initial entry, as the scope was guided in a controlled fashion cephalad. Furthermore, we were able to avoid the coiling and inadvertent displacement commonly associated with guide-wire use and performed the procedure in a comparable time to that of the traditional guide-wire method.

CONCLUSION

Retrograde intubation is a useful technique for the management of difficult airways. The use of an FFB for retrograde intubation helps anesthesiologists avoid potential complications that can arise from performing the procedure with a guide wire without direct visualization. These cases demonstrate a new update to an important technique for successfully managing patients with difficult airways.