Laryngeal Trauma During Awake Fiberoptic Intubation

Anesthesiologists often select fiberoptic endotracheal intubation as part of the care of patients with difficult airways. An important goal in airway management is to prevent damage to laryngeal structures. We report three patients who sustained airway injury during fiberoptic intubation, suggesting that this procedure may not be free of traumatic complications. Case Report Patient 1 A 69-yr-old woman was scheduled for a total knee replacement. Her history was remarkable for rheumatoid arthritis with a stable cervical spine. She had a small mouth opening and poor ability to extend the upper neck. Topical anesthesia of the airway was obtained with lidocaine (concentration 4% and 10%). A fiberoptic bronchoscope (4 mm O.D.) was placed in the trachea uneventfully. The endotracheal tube (ETT) met resistance at the first 2 attempts to pass it (7.5 mm I.D.) into the trachea. Intubation was successful at the third attempt. The remainder of the anesthetic was uneventful. Postoperatively, the patient was dysphonic (high-pitched voice). Nasolaryngoscopy revealed supraglottic swelling, and bruising of the right vocal cord (Fig. 1). Her voice gradually improved over a 2-wk period.Figure 1: View of the larynx of patient no. 1 showing edema and bluish discoloration of the right vocal cord.Patient 2 A healthy 32-yr-old man was involved in an automobile accident that resulted in fracture of the cervical spine with instability. He was scheduled for an anterior C6-7 diskectomy and fusion. Topical anesthesia of the airway was obtained with lidocaine in preparation for an awake oral fiberoptic endotracheal intubation. The bronchoscope (4 mm O.D.) entered the trachea without difficulty and 9 to 10 attempts were made to advance the ETT (7 mm I.D.) into the trachea. Postoperatively, the patient complained of severe hoarseness and dysphagia. Videoendoscopy revealed serious traumatic laryngeal injury (Fig. 2). Six weeks later, nasolaryngoscopy showed an essentially immobile right vocal fold. The symptoms improved gradually during the following 6 mo.Figure 2: Examination of the larynx of patient no. 2 showed normal left vocal cord. In contrast, there was extensive supraglottic swelling, incomplete glottal closure, diminished amplitude, and absent vibrations of the right vocal cord, and absent right vocal cord mucosal wave. A portion of the right vocal cord was adynamic. These findings suggested right true vocal cord fixation and traumatic arytenoids fixation.Patient 3 A 64-yr-old man was scheduled for direct bronchoscopy and esophagoscopy. His history was remarkable for several neck surgeries and radiation to treat recurrent malignancy of the retromolar trigone. His mouth opening was approximately 2 to 3 cm. Successful topical anesthesia was obtained with lidocaine. A fiberoptic bronchoscope (4 mm O.D.) was passed through the right nasal cavity into the trachea without significant resistance. After induction of anesthesia and upon surgical inspection, an extensive hematoma of the right pharyngeal mucosa was noted to extend from the soft palate to the level of the epiglottis (Fig. 3). The hematoma was incised and drained. Proper hemostasis was established in the areas of the hematoma and all biopsy sites. Emergence, extubation, and later recovery were uneventful.Figure 3: Extensive hematoma of the posterior and lateral wall of the pharynx of patient no. 3.Discussion Anesthesiologists often use fiberoptic bronchoscopes to intubate the trachea of patients with difficult airways. This report presents three patients in whom the number of attempts at threading the ETT into the trachea varied between 1 and 10 times. It is not always possible to advance the ETT over the bronchoscope into the trachea on the first attempt. When the tip of the bronchoscope is in the trachea, one cannot see the distal end of the ETT that is advanced “blindly” over the bronchoscope. Therefore, impingement of the ETT onto pharyngeal or laryngeal structures may result in airway injury, particularly in patients with inflammatory illnesses such as rheumatoid arthritis and after radiation treatments of the neck. Passage of the ETT over the bronchoscope on the first attempt is frequently (40%–66%) blocked (1). Resistance to passage of the ETT has been reported to range from 5% to almost 90%(1). Laryngeal anatomy, in addition to types, design, and flexibility of the ETT and fiberoptic bronchoscope are important factors in failure of the ETT to smoothly enter the trachea (1–4). For example, during fiberoptic intubation, the rate of failure of first passage of the ETT into the trachea was 66% with standard tube, 40% with warmed standard tubes, and 40% with (flexible) wire reinforced tubes (1). Furthermore, impingement of the ETT onto laryngeal structures occurs more frequently if the ETT has an acute bevel at the tip as compared with an ETT with an obtuse bevel or has a smoothly tapered end without a bevel (1,2,4). The extent of the gap between the ETT and the bronchoscope seems to be an especially important determinant of the ease of threading of the ETT. The larger this gap, the greater the likelihood of failure of threading of the ETT (5). Marsh (6) also reported that the use of pediatric tubes was associated with easier threading of the ETT (Table 1) (4–8). Thus, the relatively large gap often results in contact between the bevel of the ETT and laryngeal structures as the ETT is advanced toward the glottis.Table 1: Stepwise Recommendations on Advancement of a Regular-Beveled ETT During Awake Fiberoptic IntubationIn conclusion, serious airway injuries may occur during fiberoptic intubations. Injuries may be related to iatrogenic factors, anatomy, and diseases of the patient, or ETT and bronchoscope design. Additional studies are needed to determine incidences, types, severity, and mechanisms of injury that occur during this procedure.