A difficult or failed airway only occurs once every 2,200 cases. That's the good news. The bad news is that anesthesia providers are likely ill-prepared when one does occur, because most have never performed or even practiced difficult airway management. In fact, only one-third of residency programs offer training programs specifically geared to difficult airway management.

But there can be no excuses; anesthesia providers must be held to the highest standards of care. If that's not enough incentive, keep in mind that anesthesiologists are most often sued over cases in which a difficult airway presents. To maintain high standards, we must always be prepared for the worst-case scenario, armed with an understanding of airway management techniques and an array of alternative management devices.

Endotracheal exchange devices
Exchanging endotracheal tubes is a risky procedure, but it could be necessary if, for example, you can't quickly clear an acute artificial airway obstruction and you need to reintubate to reestablish the airway and let surgery continue. Several devices seek to make the procedure safer.

• Eschmann Tracheal Introducer. Also known as the gum elastic bougie, this device is popular in the United States but is considered the top choice for intubation in the United Kingdom. Useful in patients with anterior larynxes and those with limited mouth openings (such as pediatric patients), straight Eschmann tracheal tube guides are designed for ET exchange.
• Frova Intubating Introducer. A recent addition to the market, the Frova Introducer has a hollow lumen on a stiffening cannula and is compatible with Rapi-Fit adapters. The combination lets you place the device into a narrow passage to ET introduction while allowing for continued ventilation during an ET exchange. Adult and child sizes are available.
• Arndt Airway Exchange Catheter Set. This device sports a tapered end, multiple side ports and bronchoscope port, and comes packaged with a stiff wire guide and Rapi-Fit adapters. It can be used to exchange a laryngeal mask airway and ET using fiberoptic bronchoscope.
• VETT System. By integrating ultra-thin fiberoptic bundles into the ET, intubation stylets and laryngoscope blades, the end of the device produces television monitor projection. Visualizing all airway structures during intubation could be useful when managing a difficult airway.

Supraglottic ventilatory devices
Supraglottic airway devices come in several varieties: with and without directional seals and with and without esophageal sealing cuffs. What they all have in common is that they let the anesthesia provider ventilate above the glottis. The differences among models make for different sets of advantages and disadvantages. Let's take a closer look.

• Laryngeal Mask Airway. Since the LMA was introduced to clinical practice 20 years ago, it has been used in more than 100 million patients worldwide with no reported deaths. Although originally developed for airway management of routine cases with spontaneous ventilation, it's now listed in the ASA Difficult Airway Algorithm as both a ventilatory device and a conduit for endotracheal intubation. You can use an LMA in both pediatric and adult patients in whom ventilation with a facemask or intubation is difficult or impossible; as a bridge to extubation; and with pressure support or positive pressure ventilation. Variants on the LMA Classic include the LMA Flexible, LMA Unique, LMA Fastrach and, most recently, the LMA Proseal. The Proseal's modified posterior cuff improves the laryngeal seal and incorporates a second tube to provide a channel for gastric tube placement or passage of regurgitated fluid. It provides a better seal than the Classic and therefore protects the airway against aspiration more efficiently.
• Tracheal Combitube. This disposable double-lumen tube lets you ventilate using either tracheal or esophageal intubation, but can be placed without having to visualize the larynx, making it especially useful for patients with massive airway bleeding or regurgitation, limited airway access and for whom neck movement is contraindicated. Like the Proseal, the Combitube should protect against aspiration.
• Laryngeal Tube. Cleared for use in the United States in 2002, the Laryngeal Tube is multiuse and latex-free. The single-lumen silicone tube with oropharyngeal and esophageal low-pressure cuffs, a ventilation outlet in between and a blind distal tip provide ventilation and oxygenation capabilities similar to those of the LMA and Combitube.
• Pharyngeal Airway Xpress. A major evaluation study (appearing in the August 2003 issue of Resuscitation) found that this sterile, latex-free, single-use airway device intended for use during routine anesthesia procedures "is associated with too high a failure rate and too high an incidence of minor complications for routine airway maintenance."
• Glottic Aperture Seal Airway. This disposable, single-lumen airway capable of achieving a highly effective seal against and within the laryngeal inlet is expected on the market within a year.

Rescue techniques at the ready
Work with your anesthesia providers to develop a difficult airway algorithm for your facility. Decide how a difficult airway will be handled before your patient is in trouble on the OR table. Go over the equipment and rehearse the procedures involved in airway rescue. Here are some options to consider.

• Flexible fiberoptic intubation. Whether you want to assess or manage the airway, this technology has the answer. The anesthesia provider can use a fiberoptic bronchoscope either orally or nasally for both upper and lower airway problems and for when airway access is limited. Improved optics, battery-powered light sources, better aspiration capabilities, increased angulation capabilities and improved reprocessing mean the technology is more versatile than ever. Further, it's indicated for use in patients of any age and in any surgical position. If the patient can't be rescued using direct laryngoscopy because the anesthesia provider can't locate the glottic opening with the scope or because blood or secretions are present, there are other options.
• Retrograde intubation. This technique is excellent for securing a difficult airway either alone or along with other alternative airway techniques and, because of this and its simplicity, should be a skill every anesthesia provider knows. Especially useful in patients who have limited neck mobility or airway trauma, this technique is recommended for use with standard endotracheal tubes. Use with the Arndt Airway Exchange Catheter and Needle Holder to enhance patient oxygenation.
• Transtracheal jet ventilation. This method can be applied in interventional rigid bronchoscopy with a specifically designed jet valve and in fiberscopes in which the jet injector is attached to the suction channel without intervening tubing. Many commercial manual jet ventilation devices are currently available, as this is jet ventilation is a well-accepted technique. New to the market is the Enk Oxygen Flow Modulator, which is recommended for use when jet ventilation is appropriate but a jet ventilator is not available.
• Cricothyrotomy. This is a life-saving procedure and the final "cannot ventilate, cannot intubate" option in all settings' airway algorithms. The anesthesia provider can prophylactically secure a difficult airway by placing a cricothyrotomy catheter or an airway exchange catheter into the trachea to establish effective ventilation before induction of anesthesia. Needle cricothyrotomy should be performed with catheters at least 4cm long and up to 14cm in adults. Because standard plastic catheters can kink, you may want to consider buying 6Fr emergency transtracheal airway catheters (equivalent to 3mm inner diameter trach tube). Percutaneous cricothyrotomy involves using the Seldinger technique to gain access to the cricothyroid membrane. Cricothy-rotomy catheter sets are already quite user-friendly and they will soon be produced with a durable, elastic, high-volume, low-pressure cuff in a 5mm airway catheter. The most rapid technique is the surgical cricothyrotomy, which is performed by making an incision through the cricothyroid membrane using a scalpel, followed by the insertion of an endo tube.

Maximizing equipment value
While you may do cases in a facility that does general anesthesia but doesn't anticipate general airways, you still need to have a full complement of difficult airway devices on hand. Don't use the limited-budget excuse: You have all kinds of expensive equipment for the surgeons, so why not for the anesthesia providers? That said, you can still approach difficult airway equipment purchases in a practical manner; I recommend these seven basics:

• rigid laryngoscopes with all sizes of Macintosh and straight blades (stylets and bougies included)
• all sizes of the supraglottic airway device of your choosing;
• one 4mm flexible videobronchoscope set;
• two small size Combitubes;
• two cricothyrotomy sets;
• one jet ventilation set; and
• two tube-changer catheters of each available size.

I know the biggest hesitation here will be whether to splash out the money on a fiberoptic bronchoscope. Consider this: At less than $30,000, you're looking at less than $1 per use over the life of the scope (usually five to 10 years, depending on your case volume). The biggest problem, then, is not cost but whether your anesthesia providers are comfortable using the technology.

Know the patient
The best way to be prepared is to perform a pre-op assessment of every patient. Three-quarters of difficult-airway lawsuits are the result of inadequate pre-op screening. Obese patients and those with sleep apnea, in particular, are at highest risk for airway problems, and you're undoubtedly seeing more of these patients than ever. Take care to evaluate whether you face potential problems with bagmesh ventilation, using a laryngoscope, intubation or maintenance of the surgical airway.