Airway regional anesthesia for awake fiberoptic intubation.

Providing anesthetic care to the patient with a difficult airway keenly interests anesthesiologists and is a situation that often provokes much anxiety and trepidation. However, dealing effectively and safely with these patients is a skill that all anesthesiologists should be familiar with and are expected to perform with competency. Difficult airways arise from multiple causes. Access to the oral cavity can be impeded by unfavorable anatomy, such as a small mouth or receding jaw, as well as reduced mouth opening due to radiation therapy, jaw fracture, or previous head and neck surgery. Difficulty in neck extension shows up in the patient who can’t extend due to prior cervical fusion or advanced osteoarthritis. In addition, neck extension is contraindicated in patients with unstable cervical spines due to fractures, rheumatoid arthritis, Down syndrome, etc. Finally, there is a subset of patients who cannot be intubated using direct laryngoscopy due to anatomical variations, even though their airway exam appears normal. Whether the difficult airway is a known entity or is encountered unexpectedly, the clinician must be guided by the American Society of Anesthesiology (ASA) difficult airway algorithm and other options for providing anesthesia, such as the use of the laryngeal mask airway (LMA) and/or regional techniques, should be entertained. Still, in the situation where the airway must be controlled and anesthesia must be delivered via an endotracheal route, intubation through the use of a flexible fiberoptic bronchoscope is a commonly chosen method. However, this procedure does require some form of anesthesia. Rarely will patients allow their airways to be instrumented without it. Although fiberoptic intubation can be done under general anesthesia and may be advantageous in some situations, many believe that the use of regional anesthesia in the setting of a difficult airway is advantageous. Possible advantages include the fact that the patient is able to cooperate with the operator, is able to breathe spontaneously throughout the procedure, and is able to maintain airway patency though conscious control of the airway muscles. While there are many methods that may be used to provide anesthesia to the airway, descriptions of these methods tend to be widely scattered throughout various textbooks and journals, and the choice of which method to use is often based on limited information, such as institutional tradition and personal experience. A Medline search was performed for this review covering the last several decades and using multiple combinations and permutations of the applicable key terms. No previous articles were found that provided a comprehensive review of this subject. Therefore, in this review, we will cover the neuroanatomy of the upper airway and then describe several techniques that can be used to provide airway anesthesia for fiberoptic intubation. These techniques include methods of topically anesthetizing the airway by the use of sprays and direct application of local anesthetics to the respiratory mucosa, as well as descriptions of a variety of nerve blocks.