Recent developments in regional anesthesia have resulted in a number of
innovative and refined options to practitioners, often allowing regional
techniques to be used for patients with presumed difficult airways. However,
not every surgery can be performed under regional anesthesia. In addition,
even in the hands of the most skilled regional anesthesiologist, blocks are
subject to a certain rate of complications or failure.1–4 In addition, there are many situations in which the
anesthesiologist is called on to secure an airway in less than ideal
circumstances. Expertise with regional anesthesia of the airway allows
intubation in awake patients with suspected difficult intubation, upper
airway trauma, or cervical spine fractures. Therefore, it is essential that
every regional anesthesiologist be skilled in the administration of general
anesthesia and especially in the management of the difficult airway.
In recent years, there have been many advances in difficult airway
management. The introduction of the laryngeal mask airway, and later the
intubating laryngeal mask airway have changed the American Society of
Anesthesiologists' difficult airway algorithm
significantly.5 Despite new devices and techniques being
added to the arsenal daily, the mainstay of difficult airway management
remains flexible fiberoptic laryngobronchoscopic intubation. Fiberoptic
intubation can be performed under a variety of conditions. However, one
major decision must be made with every procedure: Will the patient be
intubated while under general anesthesia, or does the patient need to be
awake during intubation?6 Intubation under general
anesthesia (even with inhalational induction and spontaneous respiration)
carries the inherent risk of losing control of the difficult airway. For
this reason, many anesthesiologists, on recognition of a difficult airway,
elect to perform an awake intubation using either fiberoptic
laryngobronchoscopy or awake direct laryngoscopy.
Direct laryngoscopy in an awake, unprepared patient can be extremely
challenging. Excessive salivation and gag and cough reflexes can make
intubation difficult, if not impossible, under awake conditions. In
addition, the stress and discomfort may lead to undesirable elevations in
the patient's sympathetic and parasympathetic outflow. Several highly
effective topical and regional anesthesia techniques have been developed to
subdue these reflexes and facilitate intubation. Each of these techniques
has the common goal of reducing sensation over the specific regions that
will be encountered by the fiberoptic bronchoscope and endotracheal tube.
To decide on a proper approach to an awake fiberoptic intubation, one
must determine what structures need to be anesthetized along the two basic
routes of intubation (oral or nasal) to facilitate optimal surgical
conditions in the context of patient-specific anatomic considerations. Each
of these routes has a well-defined pattern of innervation that can be
specifically blocked to provide adequate anesthesia.
The nasal cavity is innervated by the greater and lesser
palatine nerves and the anterior ethmoidal
nerve. The palatine nerves arise from the trigeminal nerve via the pterygopalatine
ganglion and innervate the nasal turbinates and most of the nasal septum.
The pterygopalatine ganglion is located posterior to ...