Anesthesia Student Survival Guide.pdf - Index of

PhysioloGy And AnesthesiA for neuroloGic, ent, And oPhthAlmoloGic surGery ● 295
performed in some centers. Lung spirometry will commonly show evidence
of obstruction. Warning signs of impending severe obstruction include signs and
symptoms such as inability to lie flat or produce a strong cough, and also stridor,
dyspnea at rest, drooling, and baseline hypoxemia. Awake fiberoptic intubation
should always be considered in the management of a tenuous airway. In particularly
difficult airways with impending obstruction, an awake tracheostomy
under local anesthesia may be performed prior to anesthesia.
Intraoperative Issues
General anesthesia for ENT procedures can be maintained with a variety of
techniques. Total intravenous anesthesia (TIVA) may be considered in procedures
with delicate hemostasis (sinus surgery, tonsillectomy, inner ear surgery).
TIVA may help reduce bleeding and coughing at emergence, and reduce postoperative
nausea and vomiting. TIVA should also be considered in cases where
periodic interruption of ventilation is likely to be required or jet ventilation
employed. An infusion of propofol and an opioid (fentanyl, sufentanil, remifentanil)
is the most common approach.
The surgical airway is often rotated away from the anesthesia team and may
become inaccessible after surgical draping. Extreme neck extension, rotation,
or flexion for surgical positioning can result in extubation or endobronchial
intubation, respectively. Intrusion on the jugular vein during spontaneous ventilation
could result in air embolus.
As in certain neurosurgical procedures, nerve monitoring has a role in
ENT surgery when the facial, acoustic, and recurrent laryngeal nerves are at
risk. The procedures include resection of acoustic neuroma, mastoidectomy,
tympanoplasty, parotidectomy, and thyroidectomy. A specialized endotracheal
tube with electrodes located at the glottis may be used to monitor vocal cord
function. Nerve monitoring for these procedures precludes the use of intraoperative
muscle relaxation, but due to the high fidelity of EMG signals there is
rarely any need to further adjust the anesthetic management.
Neck dissection
Neck dissection is a common procedure performed to remove tumors and
lymph nodes. The procedure is often lengthy, and spontaneous ventilation
is relatively contraindicated due to possible air embolus with surgical trespass
on neck veins. General endotracheal anesthesia is the standard approach.