Crisis Resource Management of the Airway in a Patient with Klippel-Feil Syndrome, Congenital Deafness, and Aortic Dissection

Abstract

Klippel-Feil syndrome is a visually arresting deformity wherein severe restriction of cervical motion predicts a difficult airway. Even minor distraction of the neck risks cervical spine or neurologic injury, so regional techniques, awake fiberoptic intubation, or awake tracheostomy are recommended anesthetic approaches. We present a case of aortic dissection in a Klippel-Feil syndrome patient for whom congenital bilateral deafness, coupled with the urgency of the surgery, mitigated against the recommended first-choice techniques. Using anesthesia crisis resource management methods, a multi-member team rehearsed predefined roles and then managed the airway via inhaled induction of anesthesia, followed by flexible fiberoptic intubation.

In Brief

IMPLICATIONS: Klippel-Feil syndrome is a rare congenital disorder affecting cervical mobility, such that awake fiberoptic intubation is the preferred elective airway technique. We applied crisis resource management in a case of urgent surgery in which patient and surgical factors required a different approach.

Klippel-Feil syndrome (KFS) describes a heterogeneous group of patients unified by the presence of a congenital synostosis of some or all of the cervical vertebrae. Klippel and Feil¹ first described the syndrome in 1912 in patients with a triad of short neck, a low posterior hairline, and restricted motion of the neck due to fused cervical vertebrae, and their original work was reprinted in 1975. Cervical vertebrae are usually fused, limiting neck mobility.² The etiology is presumed to involve mutations or disruptions in genes regulating segmentation and resegmentation of the presomitic mesoderm.³ The incidence is estimated to be about 1 in 42,000 live births.² Numerous associated abnormalities may be present, including scoliosis, deafness, genitourinary abnormalities, Sprengel's deformity (wherein the scapulae ride high on the back), synkinesia, cervical ribs and cardiovascular abnormalities.² In one study involving 50 patients with KFS, less than half had the classic triad, whereas half had scoliosis and a third had renal dysfunction.⁴ Other anomalies found in that study included Sprengel's deformity (21 of 50), impaired hearing (15 of 50), synkinesia (9 of 50), and congenital heart disease (7 of 50).⁴

The anatomic and clinical expressions of KFS vary widely, ranging from mild cosmetic deformity to severe disability. Within this range of expression, there is a variable risk of neurologic damage from even minor cervical spine trauma.^5–9 Three specific patterns of cervical fusion create a high risk for instability: C2–3 fusion with occipitocervical synostosis, extensive fusion over several cervical vertebrae with an abnormal occipitocervical junction, and two fused segments separated by an open joint space.³ The risk of neurologic damage has prompted some to advise fiberoptic intubation (FOI) for all patients with KFS.^9,10 Even without the risk of injury due to a distracting cervical force, the combination of the short neck and fused cervical vertebrae would lead most anesthesiologists to identify these patients as possessing difficult airways. This would place the patient on the recognized difficult airway limb of the ASA difficult airway algorithm, again favoring an awake intubation (likely FOI) in most circumstances.¹¹

We report the case of a KFS patient brought to the operating room (OR) for urgent repair of an aortic dissection, whose anesthetic and airway management were complicated by congenital deafness, and whose unique circumstances posed a challenge to the conventional rubric of the difficult airway algorithm.

CASE REPORT

The patient was a 36-yr-old man with KFS with associated cervical synostosis, congenital deafness, and renal insufficiency. The patient consented to have his picture used for this case report. He was eating when he experienced the sensation of “a bubble around his heart.” This sensation quickly became a severe tearing pain that radiated from his mid-chest to his left shoulder. At hospital presentation the patient's arterial blood pressure was 200/160 mm Hg and his heart rate was 112 bpm. Computed tomography showed a Type B aortic dissection beginning just distal to the left subclavian artery and extending to the iliac arteries. Esmolol and sodium nitroprusside infusions were begun to control his heart rate and arterial blood pressure.

Beyond the presenting complaint, the patient had been followed for mild renal failure related to KFS for several years. He was also congenitally deaf and communicated primarily through his mother via American Sign Language. The patient had no allergies, took no medications, and had never had surgery.

Initial management focused on arterial blood pressure and heart rate control in the intensive care unit. During the afternoon of the third hospital day, the patient's blood pressure became labile and difficult to control pharmacologically, urine output declined, serum creatinine began to increase, and repeated computed tomography of the chest showed enlargement of the thoracic aorta in addition to the previously noted dissection. For these reasons, urgent endovascular repair of the aortic dissection was scheduled, and we were consulted for anesthetic planning and management. The proposed surgical approach was to close the inlet to the false aortic lumen using coated tubular stent grafts with likely deliberate occlusion of the left subclavian artery. The right brachial and iliac arteries would be used for arterial access. The case was booked to begin at the end of the regular OR work day, so an ad hoc anesthesia team was assembled.

Initial evaluation of the patient was performed by an anesthesiology resident and a cardiac anesthesiology fellow. Physical examination demonstrated the KFS triad and Sprengel's deformity. The patient weighed 75 kg and was 60 in. tall. The airway examination was unsettling. The patient appeared to have no neck at all; his head seemed grow right out of his chest (Fig. 1). Cervical mobility was limited to 10 degrees of head turn to the left, 15 degrees to the right, and about 15 degrees of extension. Structural factors limited movement, rather than pain, neurological symptoms or muscle tone. Neither the hyoid bone, the thyroid cartilage, nor the cricothyroid membrane could be clearly identified by palpation, although this was partly due to adiposity of the anterior neck structures. His dentition was normal, but mouth opening was limited, with an interincisoral distance of about 20 mm. The modified Mallampati score was 3,^12–14 and did not change when the extended Mallampati examination was attempted.¹⁵

Figure 1.: Photograph of the patient demonstrating an extremely short neck. He was virtually incapable of extending the neck. Mouth opening was limited, and this appeared to be due, in part to, limited neck extension.

During the preoperative interview and examination, the patient was very anxious but was able to communicate clearly and effectively through his mother as interpreter, augmented by lip-reading. Because of the patient's severe anxiety, the decision was made to bring his mother to the OR to translate our instructions and calm the patient. Furthermore, his mother had been interpreting medical encounters for him his entire life.

The case was assigned to a senior attending anesthesiologist and the cardiac anesthesiology fellow who had performed the initial evaluation. Two anesthesia residents, including the person who participated in the preanesthesia evaluation volunteered to help with the case. The attending anesthesiologist led the formulation of the plan for anesthesia, eliciting input from all members of the team. Also, the attending anesthesiologist delegated groups of tasks to each team member, confirmed by read-back acknowledging task receipt from each team member.

A multiple-contingency plan for induction of anesthesia and airway control was developed. Descriptions of the options for securing the airway that we formulated are listed in Table 1. After considering these options, our primary plan was to perform an inhalational induction, establish positive-pressure mask ventilation, attempt direct laryngoscopy for the purpose of airway assessment and providing documentation for future anesthesiologists, and insert the endotracheal tube using a flexible fiberoptic bronchoscope. A flow diagram of the primary plan and its major contingency back-ups is shown in Figure 2. The plan was verbally rehearsed in the OR immediately before the patient was brought into the room to ensure that each team member understood their role and responsibilities. A variety of sizes and types of laryngeal mask airways were prepared to serve as back-up airway conduits in the event of loss of airway control during the induction. Discussion with the surgical team included the likely difficulty of obtaining a surgical conduit to the airway. The roles assigned and performed by each team member during the induction are illustrated in Figure 3.

Table 1: Selected Options Considered for Airway Management

Figure 2.: Flow chart of the major options considered and decision branch points considered for management of the airway. FOI = fiberoptic intubation; LMA = laryngeal mask airway; VOC = view of vocal cords; DL = direct laryngoscopy.

Figure 3.: Diagram of the roles assigned and performed by each team member during the induction of anesthesia.

In the OR, standard ASA monitors were applied and an indwelling right radial arterial catheter was transduced. Two indwelling large bore peripheral IV catheters were found to run well. With the patient's mother at the bedside and the patient in the reverse Trendelenburg position, we conducted an inhaled induction of anesthesia beginning with a set concentration of 70% nitrous oxide by mask followed by introduction of sevoflurane to a fractional inspired concentration of 3%. The induction gas and drug administration is shown in Figure 4. We reasoned that initial use of nitrous oxide would help minimize unwanted hypotension during the early, potentially chaotic part of the induction. After loss of consciousness and loss of the eyelash reflex, spontaneous ventilation was maintained. The ability to control the airway via positive pressure mask ventilation was ascertained by giving a test breath in between the patient's normal breathing cycle. At this point, the mother was escorted from room. Inhaled anesthetics were changed to sevoflourane in oxygen, supplemented by small doses of propofol (Fig. 4).

Figure 4.: Screen image from the anesthesia information management system record for the induction of anesthesia. Time increases in the horizontal dimension, and each division is 1 min. Gas and IV drug administration, along with doses and timing are shown in the top part of the figure. Succinylcholine was administered after successful positive pressure face mask ventilation. Cisatracurium was administered after successful fiberoptic intubation. Hemodynamics and Spo₂ are displayed graphically over time in the lower part of the figure. Systolic and diastolic blood pressure are indicated by triangles; numerical values are on left axis. Spo₂ is indicated by the ‘+' symbol, and heart rate by circles; numerical values are given in the first right-side axis.

Before the induction of anesthesia, the patient's systolic blood pressure was 180 mm Hg despite an infusion of sodium nitroprusside. Throughout induction, the sodium nitroprusside dose was reduced, and after intubation, and with increasing doses of anesthetics, the sodium nitroprusside was gradually replaced by phenylephrine by the anesthesiologist dedicated to this task (Fig. 3), with the goal of maintaining the systolic blood pressure between 110 and 140 mm Hg.

During positive pressure mask ventilation, care was taken to minimize the force applied to the head and neck. Controlled face mask ventilation was used to increase the fraction of expired oxygen to >80%, after which succinylcholine (50 mg) was administered. Thirty seconds after succinylcholine administration, a single, gentle direct laryngoscopy with a Macintosh 3 blade was performed by an expert laryngoscopist, revealing a Cormack & Lehane grade 4 view of the glottic inlet. The laryngoscope was removed and a flexible fiberoptic bronchoscope was introduced orally, facilitated by manual extraction of the tongue. After the bronchoscope entered the trachea, a 7.5mm cuffed endotracheal tube was inserted over the bronchoscope (Video available as a Web supplement; please see video clip available at www.anesthesia-analgesia.org). The lowest recorded oxygen saturation during induction and airway manipulation was 96%. Hemodynamics and oxygen saturation data are displayed in Figure 4.

The surgeon successfully repaired the aortic dissection, including stenting across the origin of the left subclavian artery. After the procedure, the patient remained tracheally intubated and sedated and was transferred to the surgical intensive care unit. The patient was extubated on postoperative day 1 and discharged to home on postoperative day 5. The patient was alert and following all commands before extubation was attempted. An anesthesiologist was available with a fiberoptic bronchoscope in the event that reintubation was required. The patient was neurologically intact, the left arm remained adequately perfused and there were no anesthetic complications.

DISCUSSION

This patient's anesthetic care was complicated by his urgent need for vascular surgery, including a requirement for tight blood pressure control, a difficult airway, deafness and anxiety. Many potential approaches to the anesthetic would probably have been equally satisfactory. In the discussion below, we focus on the thought processes that brought us to our clinical plan, as well as the planning, team building, and rehearsal for the case. These were influenced by familiarity with Anesthesia Crisis Resource Management principles imparted to the team by annual visits to the anesthesia simulator.

Conventional wisdom under the rubric of the ASA difficult airway algorithm suggests that regional anesthesia, awake intubation, an invasive airway or cancellation while an alternative airway approach was planned would be the most prudent options. However, given the patient's condition, cancellation was not an option, and none of the other options were compatible with the absolute requirement to not provoke a hypertensive response.

Although the successful use of regional anesthesia in KFS patients has been described,^16,17 its use in this case was precluded primarily by the proposed surgical approach (multiple vascular access sites) and secondarily by the potential for severe ischemic limb pain developing in an unanesthetized limb during the case. Additional factors against regional anesthesia were the difficulty communicating with the patient during the procedure, the patient's anxiety and the possibility of conversion to open surgery.

We then considered the prospect of general anesthesia in a patient with a recognized difficult airway. Tracheostomy under local anesthesia was impractical due to the patient's anxiety, difficulty with communication and his challenging cervical anatomy. Therefore, we opted to use a less invasive initial approach to securing the airway.

FOI of the awake patient is a commonly recommended approach for KFS. Despite his anxiety, our patient appeared to be very eager to assist in his care and had the cognitive capacity to tolerate awake FOI. Nevertheless, we opted against this approach for the following reasons. Awake FOI requires the patient to cooperate with instructions. The potential need to communicate rapidly with the patient using sign language seemed potentially risky, given the challenges of patient, interpreter and equipment positioning. We were also concerned that potentially inadequate topical anesthesia or uncontrollable anxiety might create periods of hypertension during intubation. Dexmedetomidine might have provided adequate sedation, and preserved spontaneous ventilation, while decreasing sympathetic drive, but does not relieve the requirements for communication. In the end, we felt we would have better control of the patient's blood pressure and anxiety by performing an inhaled induction with preservation of spontaneous ventilation, followed by attempting intubation after anesthetic induction.

The next branch point was whether we would be able to establish controlled mask ventilation after the inhaled induction. We judged this to be a relatively safe branch point because the plan was to establish positive pressure mask ventilation over and above the patient's native ventilation, before paralyzing the patient. If controlled mask ventilation was not possible, we would withdraw the anesthetic, maintain spontaneous ventilation, and allow the patient to awaken. At this point, we would be left with our alternative of an awake FOI with dexmedetomidine supplementation. Conversely, if we were successful with controlled mask ventilation, we would deepen the level of anesthesia and administer a muscle relaxant to facilitate intubation.

After adequate muscle relaxation, we attempted a gentle direct laryngoscopy. Our goal was to examine the airway and document the laryngoscopic view for the benefit of subsequent anesthesiologists. We reasoned at the time that there would be high likelihood for further operations (to re-vascularize the left arm after subclavian occlusion, for example), and the details and findings from our airway management would be readily available in the electronic anesthesia record. For FOI, the anesthesiologist with the most experience was the operator, assisted by a second anesthesiologist. A third anesthesiologist attended to hemodynamics and monitoring, while a fourth prepared for other intubating options (Fig. 3).

All members of the team have attended Anesthesia Crisis Resource Management training at a medical simulator. This occurs as part of residency training or for biannual recertification required to retain privileges at our hospital. Crisis Resource Management training focuses on flexibility, personnel resource management, and advance planning (when possible) to manage developing crises in the perioperative environment. Particular emphasis is placed on practicing clear delegation of tasks, read-back of actions taken and tasks accepted, the establishment of role clarity among team members, and the avoidance of fixation on individual features of the case at the expense of the larger picture. We believe that this training served us well in this instance. None of the team members had worked together during the day leading up to the case. The cardiac anesthesiology fellow and the attending anesthesiologist had never met prior to the case. Nevertheless, it was possible to quickly form an anesthesia team, in part, because we were familiar with such conditions, as the typical Crisis Resource Management simulation scenario begins with an ad hoc team created as they are placed into a developing crisis.

Before induction, the team collaboratively developed a plan for induction and securing the airway, and established role clarity by explicitly delegating each group of tasks, including the role of the team leader. The team then rehearsed the primary plan and they developed and rehearsed all of the contingency plans as well. The team included, to a limited extent, the patient's mother, who served to translate for the patient during the pre-induction activities.

Our induction plan required four anesthesiologists, including an attending anesthesiologist, a cardiac anesthesiology fellow and two second-year anesthesia residents. This type of personnel support is unique, but we believe warranted, given the complexity of the case at hand. Would such resources be available at other times, such as the middle of the night, for example? In our hospital, it would be relatively easy to mobilize such resources, regardless of the hour, because of the large call team deployed to provide Level 1 trauma coverage. We also note the additional personnel were only needed for induction. Once the case was under way, it was performed by a trainee under the direction of the attending who covered an additional OR.

In summary, we present a case in which a patient with an easily recognized difficult airway presented with surgical and patient-related factors that precluded several of the recommended options in the ASA difficult airway algorithm.¹¹ Nevertheless, we were able to manage the patient's airway within the rubric of the algorithm by relying on advanced airway technology, ad hoc team training, and multiple anesthesiologists in predefined roles. Patients with KFS are rare in the population, but their medical problems bring them into anesthesiologists' practices. In one series, roughly 1/6 of KFS patients had hearing abnormalities that might limit communication and complicate anesthetic management by limiting options.⁴

Given the rarity of the syndrome, one might expect years to pass before another such patient was encountered. However, another KFS patient was successfully tracheally intubated at our institution for an interventional radiology procedure within days of this case. After the case described in our report, we became aware of an in press case series, now published, in which conventional techniques, such as direct laryngoscopy, laryngeal mask airway placement, and mask ventilation, were easily performed in almost a dozen KFS cases, although the patients were much younger and may have had more cervical flexibility.¹⁸ Nevertheless, this case series makes an important contribution because of cases like ours. Given the hearing and cognitive problems commonly associated with KFS, such patients may not all be candidates for awake FOI.