Chapter 39. Airway Management of a Patient with History of Difficult Airway Who Refuses to Have Awake Tracheal Intubation

A 46-year-old ASA III man is scheduled to have a total knee replacement. His past medical history is remarkable for severe rheumatoid arthritis (RA) with cervical spine involvement. He was recently diagnosed with atlanto-axial subluxation, but he has no neurological signs. He has a history of gastroesophageal reflux disease (GERD), but it is well controlled with proton pump inhibitors. His other medications are an NSAID and low-dose glucocorticosteroid therapy.

On physical examination, he weighs 67 kg (148 lb) and is 167 cm (5 ft 6 in) tall, his BMI is 23.9 kg·m−2. Examination of his airway reveals that he has a full beard and small chin, no teeth, 3.0 cm of mouth opening, and that his neck is fixed in moderate flexion. This same surgery was previously cancelled as the patient refused to complete an awake bronchoscopic intubation. The patient now emphatically refuses to consent for awake bronchoscopic intubation.

39.2.1 What Is Rheumatoid Arthritis? What Are the Anesthetic Implications of This Illness?

Rheumatoid arthritis (RA) is a lifelong (chronic) multisystem illness, which represents the most common form of chronic inflammatory arthritis and affects approximately 1% of adults (range 0.3%-2.1%) in the United States and Europe. Women are typically affected two to three times more often than men and the prevalence increases with age. The etiology of RA remains unknown, but it is evident that complex interaction between environmental factors (including infectious agents) and the immune system in genetically susceptible individuals plays an essential role.1 The class II major histocompatibility complex allele HLA-DR4 has been found to be a major genetic risk factor. The onset of RA is typically gradual between the age of 35 and 50, and may be of nonspecific nature.2,3 Synovial inflammation, cartilage damage, and bone erosion with subsequent destruction of joint integrity are the hallmarks of this illness. The course is characterized by symmetrical polyarthropathy and variably, considerable systemic involvement. As the disease progresses, cervical spine involvement becomes common, second only to involvement of the metatarsophalangeal joint.1

Extraarticular manifestations of RA are widespread and can affect as many as 40% of patients, 15% of whom appear to be severely affected.1,2 Many of these manifestations have a serious impact on anesthesia care. Cardiac manifestations most commonly present as pericarditis with effusion (in one-half of patients), but may also include cardiac conduction abnormality, granulomatous myocarditis, and valvular pathology. Rheumatoid vasculitis can affect almost any organ system and may produce coronary artery arteritis contributing to coronary syndrome. Pleuropulmonary pathology, which occurs more commonly in men, includes pleural disease, effusion, pleuropulmonary nodules, interstitial fibrosis, obliterative bronchiolitis, and pneumonitis. The prevalence of airflow obstruction in rheumatoid patients is remarkably high, suggesting it might be the commonest form of pulmonary involvement.4 Rheumatoid nodules and osteoporosis may develop in up to 30% of patients with RA. Neurologic manifestations may result from cervical spine subluxation and nerve entrapment secondary to proliferative synovitis or joint deformities which can produce various neuropathies.

Other important extraarticular manifestations include ocular involvement, which occurs in 25% of individuals with RA, such as keratoconjunctivitis sicca, and hematologic changes—chronic anemia and thrombocytosis.1,2

39.2.2 How Does Rheumatoid Arthritis Affect the Airway?

Airway management is one of the most critical aspects of anesthesia care of RA patients. There are several important elements implicated in how RA progression affects the airway of these patients:

1. Cervical spine. (Figure 39-1) Progression of RA of the cervical spine affects 15% to 86% of these patients, eventually leading to disintegration of cervical spine joints. Twenty-five percent of hospitalized RA patients have cervical pathology. Pain (40%-88%), neurologic deficiencies (7%-34%), and even sudden death from brain stem compression (10%)5 are possible manifestations of cervical spine involvement.1 The three most commonly observed forms of cervical pathology in RA include: (1) anterior or rarely posterior atlanto-axial subluxation (AAS); (2) vertical subluxation or atlanto-axial impaction; and (3) sub-axial subluxation. Anterior AAS, the most common of these abnormalities occurring in 43% to 86% of patients, is associated with a greater than expected mortality in this group.1,6,7 AAS is commonly associated with spinal cord compression and neurological deficits. However, absence of preoperative neurological symptoms may not assure perioperative safety, particularly under general anesthesia when neurological symptoms may not be detectable.7 Thus, specific precautions are warranted during airway manipulation and intraoperative positioning to avoid spinal cord injury. In addition, RA-related cervical spine rigidity and flexion deformity will present further complexity in airway management.7,8

2. Temporomandibular joints (TMJs) and mandible abnormalities. Up to 31% of RA patients report TMJ dysfunction. The severe form of this abnormality can lead to TMJ ankylosis and can significantly reduce the patient's ability to open the mouth. It has also been associated with high incidence of upper airway obstruction.9,10 In a study of 218 RA patients, a positive correlation was reported between the severity of RA and the range of motion of the jaw.10

3. Micrognathia. Hypoplastic mandible, another airway hazard, is found to be associated predominantly with a juvenile form of RA, in some cases as a congenital association, in others—due to affection of TMJ arthritis.11

4. Cricoarytenoid arthritis. This is reported in 30% to 50% of RA patients, and between 45% and 88% in postmortem studies.12 The prevalence of this potentially life-threatening condition seems to be much higher than expected. There are numerous reports of severe and even fatal airway obstruction in any period of the perioperative course, frequently unanticipated.12-15

5. Rheumatoid nodules. These nodules of the larynx and laryngeal deformity related to RA have been occasionally reported as a cause of airway complications that contribute to difficulties in airway management of RA patients.9,15,16

In summary, RA patients may frequently confront the anesthesia practitioner with multiple challenges in airway management throughout the perioperative course. This may be due to a severe form of a single airway–related pathology or any combination of pathologic changes such as cervical spine problems (rigidity, AAS, low cervical subluxation), TMJ ankylosis, micrognathia, cricoarytenoid arthritis, and laryngeal tissue damage. When approaching these patients' airways, the anesthesia practitioner should bear in mind that there are two separate facets of the problem: high incidence of difficult direct laryngoscopy requiring an alternative technique(s) and a danger of neurological complications as a consequence of airway manipulation. Tests of RA activity and the duration of the disease did not show direct correlation with the incidence of difficult intubation.17 Thus, meticulous preoperative airway assessment in these patients is warranted regardless of the severity and duration of disease.

39.2.3 What Is Informed Consent? What Are the Elements of Informed Consent?

Legal and moral basis of informed consent is established on the ethical principle of respect for patient autonomy and self-determination. In the United States, this is also rooted in constitutional guarantees of privacy and noninterference. In 1914, the case of Schloendorff v. Society of New York Hospital established that it was the right of "every human being of adult years and sound mind to determine what shall happen to his own body."18,19 The term "informed consent" came into common use in 1957 as a result of the case of Salgo v. Trustees of Leland Stanford Hospital, when it was postulated that physicians have a duty to inform patients about the risks and alternatives to treatment, in addition to the procedures themselves and their consequences.19 This gave the concept of informed consent its modern interpretation, which was directed to maximize the ability of the patient to make substantially autonomous informed decisions. In other words, informed consent is the process by which a fully informed patient can participate in the decisions about his or her health in a meaningful way. It is generally accepted that in order to complete a modern informed consent properly, the following seven components and principles must be established.19

1. Decision-making capacity. Decision-making capacity is a reasonable ability to understand discussed issues and make a particular decision at a specific time as well as the ability to express a preference based on rational, internally consistent reasoning.

2. Voluntariness. The voluntariness principle is based on the notion that physicians should perform procedures only on competent patients who participate willingly. Anesthesiologists may potentially compromise voluntariness through manipulation and coercion when they physically or pharmacologically restrain patients who have sufficient decision-making capacity.

3. Disclosure. The goal of disclosure is to provide comprehensive information to the patient relevant for her/his decision-making. The exact nature of the procedure must be discussed. Reasonable alternatives to the proposed procedure must be discussed revealing pros and cons of those options.

4. Recommendation. Anesthesiologists should present an expert opinion regarding advantages and disadvantages of each option. Patients can then participate in decision-making to determine the best option which suits their priorities.

5. Understanding. Considerable efforts should be made to confirm that patients understand the risks and benefits of the proposed procedures, and why those recommendations were made. Pain and distress in various patients' groups, including parturients, do not appear to impair comprehension or preclude obtaining a legally sufficient informed consent.

6. Decision. After the comprehensive information, including the anesthesiologist's recommendation, the patient takes part in the choice of the appropriate anesthetic technique. Patients may vary in their preferences for decision-making participation; therefore, anesthesiologists should thoughtfully attempt to tailor the extent of patient and physician decision-making to the individual patient and the situation.

7. Autonomous authorization. Finally, the informed consent process concludes with the patient intentionally authorizing the anesthesiologist to perform a specific procedure or intervention, and this will constitute the patient's self-determination and the basis of informed consent.

39.2.4 What Is Informed Refusal of Treatment or a Procedure? What Are the Options for the Anesthesia Practitioner in This Case?

Informed consent would be meaningless if the patient cannot also decline medical intervention based on his/her reasoning.20-22 It is essential, in recognition of patient autonomy, to show recognition and respect for different individual values that may be reflected in the patient decision-making process.23 However, if a patient rejects an anesthesiologist's advice, or requests a technique that the anesthesiologist believes is inappropriate, the focus of discussion turns from informed consent to informed refusal. In this case, in addition to all requirements similar to informed consent, the patient should be substantially well versed about the risks and benefits of refusal and, importantly—about reasonable alternatives. Despite full disclosure and proper consent procedure, some patients may occasionally demand or reject an intervention that is extremely unreasonable, and predictably associated with inappropriately high risk. Determination of an appropriate choice of anesthesia is difficult and should not be made lightly or out of convenience. The conscientious physician cannot be forced by anyone, including a patient, to practice negligently.19 It is important to remember that just as the patient can refuse to have an awake intubation, the anesthesia practitioner may also decline to provide care to a patient, unless it is an emergency. In this case, an anesthesiologist who chooses to withdraw from the patient's care is obligated to make a reasonable effort to find a competent and willing replacement.19

In this case, in which the patient refuses an awake intubation, a complete discussion and description of the process of awake intubation must take place and an assessment must be made to determine that the patient fully understands the procedure. Efforts should be put forth to assure that patient refusal is not a result of false beliefs based on misinformation, misunderstanding, or atypical and inappropriate previous experience.20,23 Other alternatives to awake intubation must then be discussed with the patient, as well as the associated risks and benefits associated with these alternatives. Finally, the patient and the airway practitioner need to be in agreement with the proposed airway management plan, especially as the patient's cooperation is required.

In an emergency situation in which the patient requires a life- or limb-saving procedure and no other anesthesia care provider is available, the anesthesia practitioner is obliged to proceed under emergency conditions and honor the refusal of the patient to have a particular technique. In this situation, complete documentation should be performed, including a disclosure note on the chart that all inherent risks of the treatment options were described to the patient. The anesthesia practitioner must convey to the patient what procedure(s) is in the patient's best interest. If the patient denies consent, it may be helpful for the surgeon and/or family members to become involved in the decision-making. If the anesthesia practitioner ultimately fails to obtain consent for a procedure and nonetheless proceeds with that procedure, he/she assumes the risk that a charge of physical assault may ensue.24

39.3.1 What Are the General Principles of Decision-Making with Regard to Airway Management Options?

When confronted with a difficult airway, either anticipated or unanticipated, the anesthesia practitioner should keep in mind practical recommendations shaped by the ASA Difficult Airway Management Guidelines.25 A number of different factors must be considered when making specific decisions while following guidelines recommendations. These factors include: the mechanism (cause) of the difficult airway, preexisting comorbidity, type of surgery, urgency of the procedure, the patient's position during surgery, the patient's mental status and degree of cooperation, availability of equipment, as well as the technical skills and the experience of the airway practitioner. A few essential conclusions can be drawn from these guidelines: (1) considerable efforts should be made to predict the possibility of difficult airway management by performing a methodical and comprehensive preoperative airway assessment; (2) thorough airway assessment may substantially reduce the occurrence of unanticipated difficult airway, however, it cannot completely eliminate it and the anesthesia practitioner always has to be prepared, mentally and physically, to deal with an unforeseen difficult airway; (3) if difficult airway is predicted, especially in patients with anticipated difficult ventilation, the airway should be secured while preserving uninterrupted spontaneous breathing until complete control of the airway has been achieved; and (4) always have a back-up plan(s) if the initial plan to secure the airway fails.25

39.3.2 What Would Be the Best Technique for This Patient?

This patient with long-standing RA presents with multiple signs of a potentially difficult airway—rigid neck, limited mouth opening, micrognathia, and a full beard. The neck deformity and the atlanto-axial subluxation will complicate positioning for airway management. On the other hand, appropriate positioning of patients with instability of the occipito-atlanto-axial complex is still poorly understood.7,26,27 Minimizing movements of the cervical spine is the best way to avoid exacerbation of AAS with neurological consequences. To achieve this goal, the most commonly recognized and recommended technique is awake bronchoscopic intubation which is considered the safest technique for securing a difficult airway in patients with RA complicated by AAS.8,26,28,29 In our case, this method serves dual purposes: protecting the spinal cord by minimizing neck movements and solving the problem of an already known difficult airway. However, this patient refuses an awake tracheal intubation, thus it is necessary to develop an alternative anesthesia plan. Bearing in mind the peripheral location of the anticipated surgery, regional anesthesia may be considered and offered as a safe and practical alternative technique.

39.3.3 How Does the Ability to Perform Mask Ventilation Influence Your Anesthesia Plan? How Do You Predict and Manage Difficult and Impossible Bag-Mask-Ventilation?

The ability to perform effective bag-mask-ventilation (BMV) is a quintessential element of anesthesia care. All types of anesthesia may require BMV: after induction of general anesthesia, following a respiratory arrest from a complication of regional anesthesia or as a result of excessive sedation. Failure to effectively provide BMV may have fatal consequences unless an emergency airway can be immediately established.

The incidence of difficult BMV has been reported to be 5% to 7.8% in patients presenting for general surgery.30-32 Five independent risk factors have been identified: a history of snoring; a BMI greater than 26 kg·m−2; lack of teeth; age greater than 55 years; and the presence of a beard.31 Other authors have also included Mallampati Class 4 and male gender as independent variables.32 Impossible BMV was found to be much less frequent—0.15%, with neck radiation changes as the most significant clinical predictor in addition to male gender, sleep apnea, Mallampati III-IV classification, and presence of a beard.33 A considerable proportion of those patients, close to 25%, were also found to be difficult to intubate.33 The patient in this case is edentulous, and has a full beard. He thus has two of the five risk factors and is considered to be at risk for difficult and potentially impossible BMV. The importance of this determination is a deliberate reinforcement of immediately available back-up plans, including performance of a surgical airway. Having pointed out the importance of preparation to anticipated difficult BMV; it is noteworthy to mention that there are a number of rescue techniques described to improve difficult BMV depending on contributing factors. For example, in a hairy situation (beard), as presented in our case, the use of a clear intravenous site dressing (Tegaderm™), a cut defibrillator pad over bearded area, or plastic kitchen wrap around the entire head has been proposed to reduce gas leaks from the face mask.34-36 Use of a small mask placed between the lower lip and nostrils or an infant mask covering only the nostrils has also been suggested.37 The last maneuver has also been described as beneficial in cases in which BMV difficulty was related to an edentulous status. It is also possible to keep a patient's dentures in place while performing BMV and then remove them just prior to intubation. Other options include using an oropharyngeal airway as early as feasible, placing gauze rolls inside the cheeks to prevent the oral cavity from collapsing. Nasal airways can also be used.

In recent years, there have been multiple reports suggesting that the laryngeal mask airway (LMA) may be an effective airway rescue device in the management of both difficult intubation and difficult BMV.38,39 However, there are instances in which the LMA insertion (on its own) may turn out to be difficult or even impossible.38,40,41 In fact, there are some reports of impossible LMA insertion in patients with diseases which limit neck movement.40,42 There are two special concerns when considering the use of an LMA in RA patients. First, extra caution should be taken during the insertion and inflation of an LMA to avoid movements in the head and neck and to avoid excessive soft tissue pressure as it may produce posterior displacement of the upper cervical spine and worsen atlanto-axial subluxation in susceptible patients.43 Second, care is necessary to minimize mucosal trauma in the supraglottic area to reduce the chance of aggravation of any cricoarytenoid arthritis. There are several reports of acute upper airway obstruction caused by this disease manifestation in association with LMA use.13,41,44

39.3.4 What Are Some Additional Preoperative Considerations that May Influence the Choice of Anesthetic Management?

1. Because of the high prevalence of cervical abnormality in RA, particularly AAS,6 with associated severe morbidity and mortality,5 preoperative imaging has been strongly recommended to determine the specific cervical spine pathology and possible instability45 (Figure 39-1). It has been shown that flexion and extension views in addition to frontal views of the odontoid are essential in complete x-ray examination of the cervical spine to detect AAS.45 The detection of cervical spine instability can significantly affect anesthetic management, favoring techniques that avoid unprotected manipulations of the neck under anesthesia. This valuable information could help to avoid neurological consequences during positioning.27,45,46 In addition, the lateral neck x-ray, obtained as part of a preoperative assessment to evaluate patients with cervical deformity, may help to estimate the angle between the oral and pharyngeal axes at the base of the tongue. If this angle is less than 90°, LMA insertion may be difficult or impossible.27,40

2. Intraoperative patient positioning can play an important role in the success of many procedures, yet caution should be used as positioning may also cause postoperative complications. Cervical involvement in RA can significantly complicate head and neck positioning. In addition, it is important to determine if the patient is able to assume the specific positioning required to perform regional anesthesia and to be awake during surgery. Special care should be taken in intraoperative positioning of RA patients due to the presence of multiple joint deformities (Figure 39-2), rheumatoid subcutaneous nodules, and possible peripheral neuropathies.47 The optimal intraoperative head position to minimize atlanto-axial subluxation in patients with RA has been reported as the protrusion position (head positioned on a flat pillow combined with a donut-shaped pillow) with support of the upper cervical spine and some extension at the craniocervical junction.7 However, another investigator has reported a case of a rheumatoid patient with anterior AAS who was markedly worsened by the sniffing position,27 which is similar to the above mentioned protrusion position; the only apparent difference being the degree of extension of the head at the occipito-atlanto-axial complex.

3. Although this patient does not indicate severe gastroesophageal reflux disease (well controlled with proton pump inhibitors), LMA insertion may be contraindicated in those patients with untreated and symptomatic GERD.38,42 These patients should be treated preoperatively with a histamine (H2) receptor blocker, metoclopramide, and a nonparticulate antacid regardless of the type of proposed anesthesia.

4. The effects of drug therapy in RA may require certain considerations in preparing for anesthesia care. In our case, long-term NSAID use may cause gastrointestinal disturbances and chronic anemia and may also cause abnormal platelet function. As far as corticosteroid therapy is concerned, contemporary recommendations are based on the drug regimen and intensity of surgical stress. Patients receiving low therapeutic doses of corticosteroids who undergo a surgical procedure do not routinely require standard stress doses of corticosteroids if they continue to receive their usual daily dose of corticosteroid.47,48

5. Another prudent element of difficult airway management is planning of extubation and the post-extubation strategy ahead of time.25 Special consideration should be given to RA patients in preparation for the post-extubation period due to the high prevalence of laryngeal involvement. Extra care should be taken to avoid post-extubation complications, for example, laryngospasm, since rescue maneuvers such as positive pressure bag-mask-ventilation will predictably be difficult, if not impossible. Laryngeal trauma during airway instrumentation, including the use of extraglottic devices, should be minimized to avoid postoperative acute upper airway obstruction caused by cricoarytenoid arthritis.12-16 Extubation over an airway exchange catheter may be an option in these patients.

39.4.1 What Anesthetic Agents Should Be Used for Induction?

If the ability to perform adequate BMV or successfully place an extraglottic device is predicted to be problematic, then uninterrupted spontaneous ventilation should be maintained during induction until the airway is secured. An inhalational induction with sevoflurane may be performed to minimize the risk of sudden loss of airway control.49-51 However, maintenance of a patent airway without cervical spine movement may be difficult. Intravenous drugs with minimal effect on the respiratory drive, such as low-dose midazolam, ketamine, or dexmedetomidine, can be titrated in combination with an inhalational agent. Administration of opioids should be minimized, as they depress respiratory drive. Muscle relaxants should be avoided unless BMV or LMA ventilation has been established. Although not considered conventionally as safe, there are reports of induction of anesthesia without maintaining spontaneous ventilation, followed by successful LMA or other extraglottic device placement in patients with limited neck mobility.39,52,53However, this should only be performed if there is a high level of certainty in the ability to provide adequate BMV or LMA ventilation following the induction of GA. Only short-acting drugs, such as propofol, should be used. Particularly thorough denitrogenation is essential in this case as it will delay oxygen desaturation in the event that there are difficulties in obtaining control of the airway.

39.4.2 Following Induction of General Anesthesia, How Should This Patient's Airway Be Secured?

Another prudent recommendation in the ASA Difficult Airway Management Guidelines regarding technique choices is: Do what you do best.25 In general, anesthesia practitioners are familiar with both the LMA-Classic™ or LMA-Unique™ and the Intubating LMA (ILMA). These devices can be inserted with relative ease and can provide adequate positive pressure ventilation, without tracheal intubation. Additionally, these devices can serve as conduits for tracheal intubation. A 6.0-mm inner diameter (ID) endotracheal tube (ETT) can be passed through a #4 LMA-Classic™, and a 7.0 mm ID ETT through a #5. ETTs have been designed for use with the ILMA or disposable ILMA, which have special shaped tips to allow easier and less traumatic passage through the glottis (up to size 8.0 mm ID) and can be passed through the #3, #4, and #5 ILMAs. Despite the reports that LMA use in RA patients may be associated with aggravation of laryngeal rheumatoid arthritis and acute upper airway obstruction,13,41,44 the literature has demonstrated that the LMA or ILMA are useful and effective devices in airway management in anesthetized patients with RA.49,54-56

The ILMA may offer potential advantages over the LMA in patients with RA, as it may be easier to insert in patients with a rigid neck57 and is a better conduit for intubation, although the LMA-Classic™ and LMA-Unique™ may be more advantageous in patients with limited mouth opening.39 This patient's airway may be secured with an ILMA following an inhalational induction with sevoflurane or an intravenous agent while maintaining spontaneous ventilation. Once good positioning of the ILMA is ascertained, a muscle relaxant can be administered. If the ETT designed for use with the ILMA is unavailable, a flexible bronchoscope (FB) can be used to guide a regular ETT into the trachea. Tracheal placement of the ETT can be confirmed bronchoscopically as well as by auscultation and capnography. The ILMA can then be removed using a special stabilizing device. If an FB is not available, a prewarmed, softened ETT can be inserted blindly through the ILMA by feeling for a loss of resistance, with good success (88%-98%).58,59 However, given the airway pathology in this patient, it would not be prudent to proceed without an FB. Compared to blind insertion of an ETT, FB assistance may provide less traumatic tracheal intubation which is beneficial to RA patients to avoid exacerbation of laryngeal arthritis. Additionally, a Cook Airway Exchange Catheter (using the Rapi-fit connector, attached to the capnograph monitor to detect EtCO2) or an Eschmann Introducer can be used to guide an ETT. If all these methods fail, the ILMA (or LMA) can be used alone for positive pressure ventilation throughout the case.

39.4.3 What Is the Role of Manual In-Line Stabilization of the Cervical Spine If DL Is Necessary? Are There Additional Methods to Improve Stability of the Cervical Spine during Airway Instrumentation in RA Patients?

The traditional standard recommendation that manual in-line stabilization (MILS) should always be applied during airway instrumentation in patients with cervical spine instability has recently been challenged. Some recent studies have indicated that direct laryngoscopy (DL) and intubation with MILS in the presence of cervical instability may worsen glottic visualization, contribute to an increased rate of intubation failure, and potentially increase pathologic cranio-cervical motion.60-62

In addition to awake bronchoscopic intubation, conventionally known as a proven technique of securing the airway in patients with cervical spine instability, there are a number of alternative methods that may be used with success in this patient population. Takenaka et al recently reported that use of the Airway Scope (Pentax) and the Eschmann Introducer in combination resulted in significantly reduced movements in cervical spine during endotracheal intubation.26 Ueshima et al have also reported the successful use of the Eschmann Introducer with the Pentax Airway Scope in patients with difficult airways.63 Other studies have used fluoroscopy to demonstrate a reduction of upper cervical spine movements during intubation using a variety of contemporary videoscopic devices.55,64 Takenaka et al employed fluoroscopic monitoring during airway manipulation to avoid excessive AAS subluxation in a patient with severe RA.26

39.5.1 What Other Methods Can Be Used to Secure the Airway after Induction?

It is essential that the prudent anesthesia practitioner should always have a back-up plan(s). In a nonemergency situation, in which the patient has received a short-acting induction agent and has not been paralyzed, he/she may be allowed to awaken. Alternative techniques to secure the airway or a regional anesthetic technique may be considered.

Although a complete list of all airway management devices and techniques is beyond the scope of this chapter, a few of the more commonly used devices and techniques will be discussed. A relatively new group of airway management devices, the video laryngoscopes, have been shown to be very effective for intubation in patients with a difficult airway.65 Both the Macintosh video laryngoscope (Karl Storz Endoscopy) and the Glidescope® (see Chapter 10) have been shown to be useful in facilitating intubation in patients with cervical spine immobilization.66 The use of a styletted ETT is recommended. The advantage of the Macintosh video laryngoscope is that either the direct view (naked eye) or the indirect view (monitor) can be used for tracheal intubation. As with traditional laryngoscopy, intubating guides can also be utilized, if necessary.

Rigid fiberoptic laryngoscopes such as the Bullard Scope (ACMI), the Upsher Scope (Mercury Medical), and the Wu Scope (Achi Corp) also have been shown to be useful in patients with limited mouth opening and neck extension,67 but they require a measure of experience to achieve proficiency. Similarly, the lighted stylets, such as the Trachlight™ (Laerdal Medical Corp), the Bonfils Retromolar Intubation Fiberscope (Karl Storz Endoscopy), and the Shikani Optical Stylet (Clarus Medical), are useful in patients with limited cervical spine mobility.68-70 Finally, retrograde intubation is a useful technique, especially when visualization of the larynx from above is impossible.71 However, since this technique is more invasive, it should be reserved as a Plan C in most hands, when the ability to ventilate is maintained (spontaneous or via bag-mask).

39.5.2 What Alternative Extraglottic Devices Can Be Used?

The Esophageal Tracheal Combitube™ is an alternative to the LMA in a difficult airway situation52,72 that requires minimal mouth opening and neck mobility for its insertion. It has been shown to be useful in providing a patent airway in a patient whose neck was immobilized in the neutral position with a halo jacket.73 Theoretically, the Combitube™ protects against aspiration since its distal cuff seals the esophagus and the tracheal lumen can be used to suction the stomach when positioned in the esophagus, yet the incidence of aspiration with the Combitube™ has been found to be similar to the LMA.74

Another new extraglottic device which could be used is the King Laryngeal Tube (LT) (Figure 39-3). This is a single-lumen tube with a ventral ventilation aperture. The LT is designed for blind esophageal insertion. It has both esophageal and pharyngeal cuffs that are connected to the same inflation line which create a seal above and below the ventilation aperture. Once the LT is inserted, ventilation with the cuffs inflated should be confirmed. An Aintree Extubation Catheter (Aintree, Cook Critical Care) mounted onto an FB (4 mm or smaller in diameter) can then be passed into the trachea using the LT as a conduit. Once the FB and the Aintree are in the trachea, the FB is removed, and a 15 mm Rapi-Fit Adapter can be attached to the Aintree to aid in ventilation and reconfirm tracheal placement by end-tidal CO2 detection. By removing the Rapi-Fit connector, the LT can then be removed and the Aintree can be used as a guide over which to advance an ETT into the trachea.75 A specially designed LT is being developed to better accommodate the passage of this catheter. Although the LT has been shown to be an effective airway device with a high rate of successful insertion,75 its use in patients with rheumatoid cervical spine has not been sufficiently studied.

A modified nasal trumpet, which is a nasal-pharyngeal airway with an additional distal hole and an attached tracheal tube adaptor, has been useful in patients with difficult airways who are anesthetized and breathing spontaneously.51,76 It can provide supplemental oxygen and anesthetic gas delivery to facilitate a flexible bronchoscopic intubation via the mouth or opposite nostril in patients in whom LMA placement has failed or was deemed to be impossible. The patient's entire upper airway (nostrils, oral cavity, pharynx, larynx, and trachea) should be adequately anesthetized. As a primary airway device, however, the modified nasal trumpet has not been shown to be effective.76

39.5.3 What Is Your Airway Management Plan If Mask Ventilation Is Inadequate and Tracheal Intubation Is Unsuccessful?

If both BMV and LMA ventilation are inadequate and intubation is unsuccessful, the emergency pathway of the ASA Difficult Airway Management Algorithm should be followed.25 A call for help should be made. Following determination of the "cannot ventilate, cannot intubate" situation, the practitioner should proceed directly to an emergency surgical or percutaneous cricothyrotomy.25 An attempt to pass the Combitube can be made while preparing to perform a surgical airway.

39.6.1 What Is the Possible Role of Regional Anesthesia for This Patient?

In patients with RA and a predicted difficult airway, awake bronchoscopic intubation is considered to be the safest and the most recommended method to establish a secure airway for general anesthesia. If this plan fails or the patient refuses an awake intubation, regional anesthesia should be strongly considered as a safe alternative approach. However, not all regional techniques are 100% effective, and any type of regional anesthesia may lead to disastrous complications requiring emergency airway management.

Although these complications are inherent to all regional anesthetic procedures, the risks vary and are based on several factors, including the type of nerve block; needle insertion; type, concentration, and volume of drug administered; and patient comorbidity. Therefore, risks and benefits of regional versus general anesthesia should be considered individually for each patient. Chelly77 provides a list of important factors that should be considered in making this decision (Table 39-1).

Contraindications to regional anesthesia should be excluded. These include infection at the site of needle insertion, systemic infection, bleeding abnormalities, allergy to local anesthetics, and lack of patient cooperation.77,78 In the case of neuraxial blocks, severe hypovolemic shock, severe aortic stenosis, and high intracranial pressure should also be excluded.

Additionally, possible complications of regional anesthesia must be considered. The risk of serious complications is approximately 0.1%.79 Local anesthetic toxicity can present either with neurological or cardiovascular symptoms, such as seizures, hypotension, and cardiac arrest.

A high spinal block, as a complication of neuraxial or major plexus blockade, can result in apnea and cardiovascular collapse. These complications may require emergency airway management. Furthermore, the possibility of hemodynamic instability during the case (eg, from significant blood loss) should be considered, as this may also require emergency airway management.

It is very important as well to determine if the patient can tolerate being awake during the procedure and communicate with the anesthesia practitioner. The patient's medical condition also influences this decision. For example, if the patient has severe untreated GERD, a regional anesthetic with the patient awake may be preferable to securing the airway after induction of anesthesia. If however, diseases such as severe chronic obstructive pulmonary disease or severe corrosive RA with spinal involvement prohibit the patient from lying comfortably flat, the airway should be secured.

One of the most important factors requiring consideration is the expertise of the anesthesia practitioner. This includes the appropriate experience in the chosen regional technique, as well as adequate experience in managing the patient's airway in the event of a complication. The anesthesia practitioner must know which nerves to block for both the surgery and possible tourniquet pain. The anticipated duration of the surgical procedure should also be considered and the anesthesia practitioner must ensure that the regional anesthetic will last at least that long, if not longer should delays occur.

All of the appropriate equipment for the performance of the nerve block(s) and possible emergency airway management must be available. Additional factors to consider include the site and type of surgery. A short toe procedure requiring an ankle block will have a lower risk of complications than a revision of a total hip replacement under regional anesthesia. There must also be adequate communication and cooperation between the surgeon and the anesthesia practitioner, and both must agree on the appropriateness of regional anesthesia. Expert help should be immediately available should complications occur. If GA becomes necessary, a predetermined strategy to manage the airway should be in place, including back-up plans should the primary plan fail. The landmarks for a surgical airway should be identified before induction of GA and the necessary personnel and equipment should be immediately available.

39.6.2 Is Neuraxial Anesthesia Appropriate for This Patient?

When considering neuraxial blocks in patients with RA, spinal deformity may make the technique challenging; however, the prevalence of lumbar spine involvement in RA patients has not been found to be excessive.80 Indeed, a number of reports confirm successful use of spinal and epidural blocks for lower limb surgeries in these patients.47,81,82 Recently, there was an interesting report by Leino et al which stated that the mean spread of sensory block after the injection of plain bupivacaine was 1.5 segments higher in patients with RA than in those without this disease.81 Keeping in mind that the patient in our case has a well-known difficult airway, maximum efforts should be made to avoid excessive cephalad spread of spinal anesthetic which can cause respiratory arrest and cardiovascular collapse. To keep control over the spread of neuraxial anesthetic, special attention should be given to the details of the technique, including baricity of local anesthetic, total dose and patient position. Furthermore, a catheter-based neuraxial technique should be considered as it can offer even better control over the extension of the block as compared to the single-injection technique.

This patient is on an NSAID. However, a recent Consensus Conference on Neuraxial Anesthesia and Anticoagulation78,83 concluded that NSAIDs appear to represent no added significant risk for the development of spinal hematoma in patients having epidural or spinal anesthesia.

39.6.3 Which Regional Anesthetic Technique Would Be Most Suitable for This Patient?

A better choice for this patient may be the performance of peripheral nerve block(s), if appropriate for the surgery. Peripheral nerve blocks used as a main mode of anesthesia for RA patients have been reported by many authors.84,85 Since the patient is scheduled for knee surgery, an anterior-approach femoral nerve block, combined with sciatic nerve block would be most appropriate. A local anesthetic mixture of mepivicaine 1.5% and ropivicaine 0.5%, using a total volume of 25 to 30 mL for each nerve block will provide superb anesthesia for a total knee replacement and possible tourniquet pain.86 Additional obturator and lateral femoral cutaneous nerve blocks may be required, depending on the patient's response. Although a lumbar plexus block could be considered, spinal deformities may make this approach more difficult and this block has a higher risk of complications, including those requiring emergency airway management. A catheter-based technique can also be used.

This case presentation of a surgical patient with a known difficult airway who refuses to have an awake tracheal intubation presents the anesthesia practitioner with a number of challenges. In addition to resolving ethical and medico-legal issues related to patient refusal of a medically indicated intervention, the anesthesia practitioner has to come forward with practical options that can be offered and accepted by the patient and surgical team. In the management of the anticipated difficult airway, the anesthesia practitioner must be familiar with a number of alternative techniques to secure the patient's airway regardless of the anesthesia plan selected. The ASA Difficult Airway Guidelines form the basis for deciding which technique is most appropriate for each individual patient. The anesthesia practitioner should perform the technique with which he/she is most comfortable and skilled, and should always have several alternative techniques available in the event the primary technique fails. Regional anesthesia may be an appropriate option for patients with a recognized difficult airway, if certain conditions are met, and the patient, surgeon, and anesthesia practitioner are prepared to overcome the failure or complications of this technique.