- The anesthetic goals for endoscopy include
profound muscle paralysis to provide masseter muscle relaxation
for introduction of the suspension laryngoscope and an immobile
surgical field, adequate oxygenation and ventilation during surgical
manipulation of the airway, and cardiovascular stability during
periods of rapidly varying surgical stimulation.
- It is crucial to monitor chest wall motion constantly
and to allow sufficient time for exhalation to avoid air trapping
- The greatest fear during laser airway surgery
is a tracheal tube fire. This can be avoided by using a technique
of ventilation that does not involve a flammable tube or catheter
(eg, intermittent apnea or jet ventilation through the laryngoscope
- Techniques to minimize intraoperative blood loss
include supplementation with cocaine or an epinephrine-containing
local anesthetic, maintaining a slightly head-up position, and providing
a mild degree of controlled hypotension.
- As always, if there is serious doubt regarding
potential airway problems, an intravenous induction should be avoided
in favor of awake direct or fiberoptic laryngoscopy (cooperative
patient) or an inhalational induction, maintaining spontaneous ventilation
(uncooperative patient). In any case, the equipment and personnel
required for an emergency tracheostomy must be immediately available.
- The surgeon may request the omission of neuromuscular
blocking agents during neck dissection or parotidectomy to identify
nerves (eg, spinal accessory, facial nerves) by direct stimulation
and to preserve them.
- Manipulation of the carotid sinus and stellate
ganglion during radical neck dissection (right side more than the
left) has been associated with wide swings in blood pressure, bradycardia,
dysrhythmias, sinus arrest, and prolonged QT intervals. Infiltration
of the carotid sheath with local anesthetic will usually ameliorate
these problems. Bilateral neck dissection may result in postoperative
hypertension and loss of hypoxic drive because of denervation of
the carotid sinuses and bodies.
- Patients undergoing maxillofacial reconstruction
or orthognathic surgical procedures often pose the greatest airway
challenges to the anesthesiologist. If there are any anticipated
signs of problems with mask ventilation or tracheal intubation,
the airway should be secured prior to induction.
- If there is a chance of postoperative edema involving
structures that could obstruct the airway (eg, tongue), the patient
should be carefully observed and perhaps should be left intubated.
- Nitrous oxide is either entirely avoided during
tympanoplasty or discontinued prior to graft placement.
Never are cooperation and communication between surgeon and anesthesiologist
more important than during head and neck surgery. Establishing,
maintaining, and protecting an airway in the face of abnormal anatomy
and simultaneous surgical intervention can test the skills and patience
of any anesthesiologist. Clearly, a thorough understanding of airway
anatomy (see Chapter 5) and an appreciation
of common otorhinolaryngological and maxillofacial procedures will
prove invaluable in handling these demanding anesthetic challenges.
Endoscopy includes laryngoscopy (diagnostic and operative), microlaryngoscopy
(laryngoscopy aided by an operating microscope), esophagoscopy,
and bronchoscopy (discussed in Chapter 24).
Endoscopic procedures may be accompanied by laser surgery.
Patients presenting for endoscopic surgery are often being evaluated