Airway emergencies encompass a broad group of situations. They may be anticipated or arise unexpectedly. They may be due to the patient’s normal anatomy, a disease, or the procedure the patient is undergoing. They are always a challenge and require excellent team dynamics to prevent patient injury.

The American Society of Anesthesiologists (ASA) has created practice guidelines for difficult airway management. The guidelines were first published in 1993, as a result of an analysis of lawsuits against anesthesiologists pointing to numerous poor patient outcomes related to the inability to successfully obtain or maintain an airway. The guidelines were then revised and republished in 2003. These guidelines help the anesthesiologist think proactively about factors that predict if a patient might have a difficult airway, what to consider when creating a plan to manage the airway, and what to do if difficulties during airway management are encountered. They are guidelines and not standards—which means that they are recommendations for practice, not rules. The individual anesthesiologist may use his or her own judgment about how any individual patient may be appropriately treated, and whether the patient condition or situation is best suited for following the guidelines or a different course of action.

It is important that the anesthesia technician is intimately familiar with these guidelines as well, because it will help the technician anticipate what equipment or maneuvers may be needed during management of a difficult airway. Can you have a key piece of equipment prepared and ready to be handed in before the anesthesia provider even asks for it? This chapter reviews the ASA difficult airway algorithm and highlights the equipment needs for each clinical situation.

The first step in the algorithm is to evaluate the patient for potential difficulty with ventilation or intubation. This will include a history and physical exam looking for indicators that would suggest difficulty. Predictors of difficult mask ventilation include presence of a beard, obesity, absence of teeth, and a history of sleep apnea. Predictors of difficult intubation include limited mouth opening, large tongue, limited neck extension, inability to push the mandible forward, or previous history of difficult intubation. Additional factors that could make ventilation or intubation difficult, and can even make establishing a surgical airway difficult, include the presence of infection, a tumor, or surgical changes in the neck. A fourth area to consider is the patient’s ability to cooperate with maneuvers performed while the patient is awake. For example, children, individuals with developmental delay, or intoxicated patients may be unable to cooperate with particular airway management techniques (starting an intravenous [IV] line, awake fiber-optic intubation, etc.). Identifying potential problems in any of these areas will affect how the anesthesiologist plans for airway management. It is also important to realize that these factors are not 100% successful in predicting that a patient will be easy or difficult to mask ventilate or intubate. Every anesthesiologist has been uncomfortably surprised by the patient anticipated to have an easy airway but turned out to be difficult to ventilate or intubate.

The second step in the algorithm is the admonition to pursue the delivery of oxygen at all times during the process of airway management. One might think that this would be obvious; however, the ASA task force recognized that there were many instances of patient injury that resulted
from a failure to provide oxygen. The astute anesthesia technician can be watching for opportunities to facilitate oxygen delivery, such as holding the mask for preoxygenation, or offering to place a mask with blow-by oxygen during a fiber-optic intubation.

The third step is developing a plan for airway management, and the algorithm asks the anesthesiologist to consider three steps in particular about the plan (Fig. 60.1). First, the anesthesiologist needs to decide whether airway management should proceed awake or asleep. This will depend on several conditions, such as whether the patient is anticipated to have difficulty with both intubation and ventilation and whether the patient is able to cooperate. The second step is to decide whether the patient should have a noninvasive or invasive approach planned. Invasive in this setting refers to a surgical airway, such as cricothyrotomy or tracheotomy. The task force specifically called out invasive airways because it wanted to remind practitioners to consider them as a legitimate first step in airway management. These procedures can be remarkably well tolerated by patients; however, many anesthesiologists are reluctant to consider these options and attempt other airway techniques first. In some situations, other techniques are not likely to succeed, and when an invasive airway becomes necessary it is a true emergency and is much more difficult to perform than in the controlled circumstances that may have been present at the beginning of the airway management process. The final step in planning airway management is deciding whether to maintain spontaneous ventilation—or in other words, should the patient be paralyzed or not? This will depend on the difficulty of anticipated mask ventilation. If difficulty with mask ventilation and intubation is anticipated, it is unwise to take away the patient’s ability to breathe on his or her own.

The next boxes in the algorithm refer to the actual execution of the airway management plan (Fig. 60.2). Box 4A is used if the initial attempt at establishing an airway is performed with the patient awake. Most often, this will be with a noninvasive technique such as fiber-optic bronchoscopy, retrograde wire, or video laryngoscopy (e.g., Glidescope). However, as mentioned earlier, an invasive technique may be appropriate. Either the surgeon or anesthesiologist may perform an invasive airway, although if it is planned, it is more likely to be performed by a surgeon. Hopefully, the planned awake technique is successful, but if it is not, there are three options outlined in the algorithm. First, give up and cancel the case. Send the patient home, let any swelling or bleeding resolve, and the patient will live to see another day. Second, consider whether the case could be done under regional anesthesia or
with a supraglottic airway instead of intubating. Third, if it is an emergent case that requires a tracheal tube, an invasive technique should be considered.

Box 4B describes the airway management plan for those patients starting out with general anesthesia (Fig. 60.3). Usually the result will be successful intubation without difficulty. However, intubation may be difficult in approximately 5.8% of cases. If initial attempts are unsuccessful, the anesthesiologist can try using a different laryngoscope or blade, changing the patient position, or even having a more experienced anesthesiologist perform the intubation. If difficulty persists, the algorithm asks the anesthesiologist to consider three things: (1) call for help (anesthesia technicians should respond to calls for help in the operating room [OR] and be prepared to bring in equipment or lend a hand), (2) allow the patient to return to spontaneous ventilation, or (3) awaken the patient. These latter two choices will be dependent in part on which drugs and how much of them the patient has received. It may not be possible to wake a patient up or to get him or her to breathe spontaneously if he or she has received a large dose of a neuromuscular blocker.

In between attempts to intubate, the anesthesiologist should try mask ventilation to maintain oxygen saturation. If mask ventilation is adequate and oxygenation can be maintained, even though there is difficulty intubating, the situation is not an emergency. Oxygen can be provided to the patient and carbon dioxide can be breathed out effectively if mask ventilation is working well. This means there is time to get additional equipment, such as fiber-optic bronchoscopes or other difficult airway equipment, ready and available. Unfortunately, it is possible that mask ventilation may get more difficult
over time; therefore, it is still important to move expeditiously. In addition, patients at risk for aspiration are particularly vulnerable during this period of mask ventilation, until a tracheal tube is successfully placed. There are several different options available for intubating at this point in the algorithm, such as fiber-optic intubation with either a rigid video laryngoscope such as the Glidescope or flexible bronchoscope, retrograde wire intubation, or intubation through a laryngeal mask airway (LMA^TM). These options are discussed more fully in other chapters (see Chapter 18 and Chapter 35).

If mask ventilation is not effective, the situation rapidly becomes emergent. Steps to attempt to make mask ventilation work may include nasal
airways, oral airways, or two-handed holding of the mask with an assistant to “squeeze the bag.” The anesthesia technician may be called upon to squeeze the ventilation bag if the anesthesia provider is using both hands to hold the mask. If these steps are not successful, then the next step suggested by the algorithm would be to place a supraglotic airway (e.g., laryngeal tube or laryngeal mask). The airway should be sized appropriately for the patient. It may be a supraglottic airway of any type, although there may be a preference toward a supraglottic airway that allows subsequent intubation without removing the airway (e.g., intubating laryngeal masks). However, there should be no delays in looking for one type of supraglottic airway over another in this critical situation. If ventilation is effective through the supraglottic airway, then there will be many sighs of relief. Further attempts at intubation can be handled under more controlled circumstances.