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Managing the Difficult Airway
Pre-assessment strategies to avoid challenging intubations before they start.
Adam Dorin
Publish Date: May 13, 2008   |  Tags:   Anesthesia

One of the greatest challenges we anesthesia providers face is protecting and maintaining a safe and patent airway so that patients can get oxygen and anesthetic agents as well as release expired carbon dioxide and residual inhalational gases. But what about those patients whom you just can't intubate? In this article, we'll tell you how to single out patients who have difficult airways before they arrive in your ORs and how to tailor a management plan just for them.

Hone your judgment, not your skills
Many would argue that proper airway management turns on only one point, and that is having expert skills when placing an endotracheal tube or laryngeal mask or when rescuing a difficult or failed airway. But I believe that nothing could be further from the truth.

The best anesthesia providers know that a long-term clean record of patient care begins with judgment. They need to detect potential difficult airways before entering the OR to allow the necessary pre-anesthetic preparation. In some facilities, this may mean rescheduling a case to maximize backup support to prepare for airway failure. But in most cases, making a good judgment involves choosing the type of anesthetic and possibly collaborating with the surgeon to use alternative techniques that would make general anesthesia unnecessary. For example, the anesthesia provider could use a regional anesthetic or intravenous sedation with local anesthetics provided by the surgeon on a patient who seems likely to have a difficult airway.

Exercising good judgment means taking a step back and viewing the patient's entire medical state. Every physiologic system has implications on the others, so a proper history and physical exam is the first and most important step in the planning stage to avoid airway mishaps during surgery. Here are five airway management pearls that can add a little edge to the already experienced anesthesia provider's skills.

Assess any history of difficult airway problems in past surgeries. Some phrases to look for in the patient's history include "hard-to-place tube," "could not intubate," "had to cancel surgery," or "had to use special equipment to breath for me."

Determine whether the patient has a history of anatomical issues that could point to potential airway-related problems. This could mean TMJ (temporomandibular joint) problems, sleep apnea, trauma to or surgery on the head and neck area, a history of tracheostomy, tumors or masses in the head or neck area, or difficulty swallowing.

Conduct a thorough physical exam. Providers must examine the patient's range of motion and movement about the head and neck, and look for evidence of prior cervical spine surgery such as a scar. They should check the patient's ability to fully open his mouth while looking for evidence of a limited range of jaw opening due to TMJ pain, and determine how well they can see the back of the patient's palate/uvula (see "Use PUSH to Quickly Check an Airway" on page 39). If the patient has a good range of motion in the neck and the uvula and the space between the uvula and the back of the tongue are visible, those are usually good signs.

Check for obvious indications that the patient's head and neck anatomy is in any way different from the average patient's. This includes gross micrognathia, significant dental aberrations, protruding front/upper teeth or any gross asymmetries.

Give the patient a basic heart and lung exam. This will help to insure that no concomitant medical problems could impact the patient's ability to tolerate a general anesthetic.

Are you prepared for the worst?
Even when an anesthesia provider is working with the most cooperative surgeon, there may be situations when a patient shows all the signs of a potential difficult airway but still needs a general anesthetic. When that happens, you need to fully explain the added procedures and risks while obtaining the patient's preoperative consent.

You should have a stocked difficult airways cart on hand in case of emergencies. At the minimum, this should include:

  • Intubating laryngeal mask airways (LMA) and regular basic LMAs. Remember, it's better to "save" an airway with minimal trauma, bleeding and duration of hypoxia — which a basic LMA or other type of supraglottic airway can quickly provide — than to attain the "ideal" airway. If an airway problem develops, providers must quickly establish an airway, ventilate with 100 percent oxygen and let the patient wake up. That will let them reassess various anesthetic options and decide whether the case should proceed on an elective, outpatient basis.
  • Elastic bougies.
  • Lighted stylet wand.
  • Jet ventilation setup.
  • Flexible-tip, directional endotracheal tubes of various sizes, with intubating stylets.
  • Cricothyrotomy tray.

Most experienced clinicians look back on the days of the flexible fiberoptic scope intubation set-ups with, for lack of a better word, amusement. Although using a fiberoptic bronchoscope during an awake intubation, with properly applied local anesthesia to the oral or nasal airway passages and adequate lubrication, can be the optimal approach to a known difficult airway, it is rarely the best, most efficient or most effective method of rescuing a difficult airway once a problem occurs. These take too much time to use, which can raise the patient's risk, and most anesthesiologists and nurse anesthetists often don't have regular practice and solid skills with these instruments.

Every anesthesia provider prefers a certain type of laryngoscope blade. Regardless of their favorite, success and comfort with an instrument under routine conditions usually translates into a higher degree of success under stressful conditions if the same devices are used and the same procedures followed. In other words, providers should do what they're used to doing and what they're good at, because emergencies are not good times to experiment with new devices.

Several products on the market featuring some sort of fiber-optic camera fitted atop a uniquely fashioned laryngoscope can be excellent adjuncts when establishing an airway, but should be used in an emergency only if one has some degree of familiarity with the functionality of the device (see "The Latest in Video Laryngoscopes" on page 40). The best new airway devices have improved lighting control and an altered design that allows for better visualization of the airway's anatomic structures. They're not cumbersome and are easy to use quickly in an emergency.

Most seasoned clinicians will tell you that a skilled and experienced anesthesia provider can handle some of the most challenging and unexpected airway emergencies with little or no disruption or patient injury without attracting much, if any, attention to themselves. All they usually need is a styleted and often slightly smaller endotracheal tube that is gently floated, with the assistance of cricoid pressure, under the epiglottis. This technique can work even when they can't visualize the vocal cords; if done gently and with skill, it can quickly obviate the need to resort to additional airway-saving procedures.

Use PUSH to Quickly Check an Airway

One popular test for determining a patient's potential airway difficulty is the Mallampati Airway Score. The patient's class on this scale can give you a better idea of how easy intubation will be, and can be as simple as noticing what you see when the patient opens his mouth:

Class 1. Can see PUSH: Pillars, Uvula, Soft palate, Hard palate

Class 2. Can see USH: Uvula, Soft palate, Hard palate

Class 3. Can see SH: Soft palate, Hard palate

Class 4. Can see H: Hard palate

Although this test is quick and easy, use other tests, too. As Ron M. Walls, MD, chair of the department of emergency medicine at Brigham and Women's Hospital in Boston, says in the July 28, 2006, Journal Watch Emergency Medicine, "It doesn't predict difficult bag-mask ventilation and shouldn't be used alone."

— Adam F. Dorin, MD, MBA

Ready for emergencies
The effective and smooth handling of a difficult airway, whether it's an anticipated event or an emergency situation, is emblematic of the way a surgical facility is run and managed in general. Although it may be the anesthesia provider on the front line, he needs to have the support necessary to make the right decisions. Medical directors, anesthesiologists and nurse anesthetists who can stand behind a record of safe medical care will be on top of the supplies, training and other steps necessary to manage difficult airways.

The Latest in Video Laryngoscopes
— Compiled by Nathan Hall

LMA North America
McGrath Video Laryngoscope
(858) 587-4025
www.lmana.com
List price: $9,295
FYI: This lightweight laryngoscope has a camera stick that moves along with the handle, which the manufacturer says makes it easy for the physician to manipulate in all mouth sizes. The camera stick can also be removed for more flexibility when treating patients with extremely small mouths or large chests. The fully portable instrument runs on one AA battery and has no external cables.

EZC Medical
Intubaid
(415) 561-2555
www.ezcmedical.com
List price: $79.95 for the straight malleable stylet; $89.95 for the flexible stylet (not yet on the market)
FYI: This disposable stylet can come in handy for anesthesia providers who only anticipate encountering a few difficult airways a year and don't want to invest in capital equipment, says the company. It's fully portable, fits over any brand of endotracheal tube and can display on any standard monitor or PC as well as with a handheld monitor (sold separately).

Pentax Medical Company
AWS-S100
(800) 431-5880
www.pentaxmedical.com
List price: $9,995 for the video laryngoscope; $500 for a kit with 20 PBlades/handle drapes.
FYI: Displays a target symbol on the monitor that's combined with a tube guide on the blade to highlight the path of the endotracheal tube, says the manufacturer. All the provider has to do is line up the target system with the glottic opening and he can intubate the patient quickly and accurately. Single-use PBlades are transparent so they won't affect the image quality, says Pentax.

Verathon
GlideScope Cobalt
(800) 331-2313
www.verathon.com
List price: not disclosed
FYI: Throw away a single-use flexible sheath and replace it before the next case. This eliminates disinfection time and the risk of patient-to-patient transferred diseases. The video baton features a high-resolution camera. The sheath can be angled up to 60 degrees to provide clear views without fogging.

King Systems Corporation
Airtraq
(317) 776-6823
www.kingsystems.com
List price: not disclosed
FYI: The single-use Airtraq features two separate channels: an optic channel for the video system and a guiding channel that holds the endotracheal tube to guide it through the vocal cords. The manufacturer says these let anesthesia providers intubate the patient in any position without neck hyperextension with only 30 to 60 seconds of setup time. Also has a built-in anti-fog system and a low-temperature light to facilitate viewing inside the airway.

Olympus America
LF-V EndoEYE Intubation Videoscope
(800) 848-9024
www.olympusamerica.com
List price: not disclosed
FYI: Designed specifically for anesthesiology, the LF-V has a distally mounted CCD and a single connection for the light guide and camera head. This setup, says the manufacturer, means you get a bright and sharp image. Also, since the system has no fiberoptic bundles it will be more durable than many other laryngoscopes on the market. Easy to reprocess because it can be fully immersed in fluid.

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