Management of the difficult airway remains a complex problem for anesthesiologists, although a number of approaches have been described. Fiberoptic intubation remains one of the more successful and frequently utilized methods to access the difficult airway, but this approach presents a number of challenges as well. These include the presence of blood and secretions in the nasal and pharyngeal airways, edema from transoral attempts, or anatomic distortion from radiation and prior surgery, all of which obscure the endoscopic view.
A variety of maneuvers can address these challenges in the perioperative or emergency settings, but often are not optimal. These include the use of the jaw thrust, an Ovassapian transoral airway, or the laryngeal-mask airway (LMA). However, each of these is suboptimal, particularly in patients with altered anatomy or Mallampati class IV airways. Transnasal fiberoptic intubation (TFOI) can be advantageous by circumventing the oral airway, but visualization of the laryngeal airway may also be obscured due to prolapse of the tongue base or pharyngeal walls.1
In this report, we describe the utilization of a practical and cost-effective adjunct to transnasal fiberoptic intubation in the difficult airway that can be universally implemented by anesthesiologists and otolaryngologists. The simple adaptation of a nasopharyngeal trumpet to serve as a direct conduit to the laryngeal airway for facilitating fiberoptic intubation is described.
MATERIALS AND METHODS
Ten patients underwent transnasal fiberoptic intubation for the perioperative anesthetic management of the airway. One representative case is presented. In all cases, a 36 French nasopharyngeal trumpet (NT) was longitudinally incised along its entire length with a scalpel, lubricated with 2% lidocaine HCl jelly (Fig. 1) and utilized for fiberoptic guidance. The nose was treated with phenylephrine HCl 0.5% prior to a traumatic placement of the largest NT airway tolerated, which then facilitated guidance of the endoscope and endotracheal tube into the larynx for successful intubation in all cases.
A 57-year-old male with a history of obstructive sleep apnea, morbid obesity, and an advanced cancer of the head and neck with extensive neck metastases presented for surgical management of his disease. Examination of the airway revealed a Mallampati class IV airway, oral aperture <3cm, and a limited neck extension; all three are clinical factors that are known to be associated with a difficult airway.2 The patient had previous head and neck surgery in which multiple transoral and transnasal techniques were implemented by several experienced anesthesiologists, with limited success.
Prior to induction, the upper aerodigestive tract was topicalized with 4% lidocaine before airway manipulation. Thereafter, the patient was sedated with titrated doses of midazolam, dexmetomidine, followed by infusions of propofol at 12.5 mcg/kg/min and dexmedetomidine at 0.5 mg/kg/hr. After the patient was sedated to a satisfactory level, the nasal cavity was serially dilated with lubricated nasopharyngeal airways (28 French to 36 French). The 36 French NT airway was incised longitudinally, inserted into the nares, and the endoscope was advanced through the NT (Fig. 1).
In this patient, we elected to use a large endotracheal tube (ETT) that could be accommodated by the size of his nares. However, smaller ETTs can be utilized in those with small nasal apertures. After loading the 8.5 ETT onto a 9 mm fiberoptic bronchoscope (Olympus, Center Valley, PA), the airway was visualized fiberoptically (Fig. 2A). The tip of the NT was at the glottic opening in all cases, allowing immediate visualization of the vocal cords without obstruction. After visual confirmation of the vocal cords, the endoscope was advanced into the trachea and the NT was easily removed from around the bronchoscope through the longitudinal incision (Fig. 2B). In this manner, constant visualization of the airway was maintained without obstruction, and the ETT was then guided into the trachea and was secured (Fig. 2C).
Fiberoptic intubation was performed successfully in all cases, and the trumpets were easily removed without any complications.
In this report, we describe a cost-effective application of a nasopharyngeal trumpet to facilitate transnasal fiberoptic intubation in the difficult airway. The advantages of this technique include: 1) the ubiquitous availability of the NT, 2) minimal cost, (3) ease of use and applicability, and (4) the universal comfort of anesthesiologists with the appliance and TFOI approach.
A significant challenge to intubation in the complex airway is the collapsible nature of the oropharynx and hypopharynx due to the lack of a bony framework in these regions.3 Furthermore, the induction of anesthesia exacerbates the reduction in muscle tone, leading to prolapse of the soft palate, base of tongue, and epiglottis, which can obscure the supraglottis and the laryngeal introitus.3 In certain situations, the jaw thrust or chin lift maneuvers do not relieve this obstruction.
The nasopharyngeal trumpet is a simple and economical piece of equipment that can aide not only in ventilation, but can also facilitate TFOI. It offers several advantages over other commercially available oral airways, and can enhance nasal intubation. Additionally, the NT airway is well tolerated by both conscious and sedated patients, as it is less prone to induce a gag reflex because the lingual branch of the glossopharyngeal nerve is responsible for the gag reflex and this is bypassed.4 One unique design feature is the anatomically correct curvature of the NT airway, which places the tip of the tube directly over the glottic opening. The nasopharyngeal airway can be easily inserted after the length of the airway is approximated (distance from the nares to the auditory meatus of the ear), and the nasal airway can be dilated with minimal bleeding and discomfort. The relative ease of its removal, accomplished by the longitudinal fissure, is remarkable, even with the ETT in place. Although a risk exists for potentially advancing the proximal end of the NT beyond the nasal sill into the nares, this has not been an issue to date. One other weakness of the approach is the inability of this technique to address intraglottic and subglottic disease. In most of these situations, a surgical airway or rigid bronchoscopy is necessary for management.
A variety of commercially available oral airways are currently available, such as the Berman Oropharyngeal Airway (Vital Signs, Totowa, NJ), Williams Airway Intubator (Williams Airway Intubator Ltd., Calgary, Canada), the Ovassapian Fiberoptic Intubating Airway (Kendall, Argyle, NY) and the LMA, which can facilitate fiberoptic intubation and can temporize the difficult airway during intubation.5,7 However, these are significantly more expensive than the commonly available nasopharyngeal airways. Moreover, these devices have several drawbacks, including: 1) ETT size that can be accommodated, 2) potential damage to the ETT balloon, and 3) operator experience.6 Additionally, certain ear, nose, and throat; dental; and head and neck cases require a transnasal airway, and these patients often present the greatest challenges to securing a safe airway. Hence, the ubiquitously available nasopharyngeal airway can be easily modified and used to place the ETT transnasally.
The utilization of the nasopharyngeal trumpet as a conduit for the fiberoptic scope in both awake and sedated patients can allow the anesthesiologist to perform a rapid and relatively atraumatic assessment of a suspected difficult airway, particularly in the patient with head and neck cancer. Although having fallen out of favor since the introduction of fiberoptics to the anesthesiologist's armamentarium, many anesthesiologists in the past relied upon the nasopharyngeal airway as their rescue method for blind intubation, as the axis of the trachea can potentially be more easily aligned with this technique .8–10 Similarly, the nasopharyngeal airway can serve as a temporizing airway in emergent situations and often provides the path of least resistance to the supraglottis, immediately above the vocal cords.
Implementation of a novel modification to the nasopharyngeal trumpet can facilitate TFOI in the difficult airway. The approach makes use of readily-available equipment to rapidly access the larynx in patients with altered anatomy. The ease and low cost associated with this simple longitudinal split in a nasal trumpet should allow it to be seamlessly implemented by other practitioners in securing the most challenging airways.