Anesthesia for ENT surgeries Flashcards
Unique challenges for ENT surgeries include
use of specialty equipment- lasers, endoscopes, special ET tubes
use of specialized anesthetic/ventilation techniques
often have a preexisting tenuous airway- tumors, abscesses, congenital disorders
increased risk of airway fire
share airway with surgeon- access to patient is limited or nonexistent
The four cranial nerves that supply sensory & motor function to the airway include
trigeminal, glossopharyngeal, facial, & vagus
The trigeminal nerve provides
sensory innervation to the face
Three divisions include: ophthalmic, maxillary & mandibular
The glossopharyngeal nerve provides sensory innervation to
posterior 1/3rd of the tongue
oropharynx
vallecular
anterior epiglottis
The glossopharyngeal nerve is responsible for the afferent limb of the
gag reflux
The facial nerve is located at the
tragus of the ear
-supplies motor and sensory function to the face for facial expressions
The six major branches of the facial nerve include:
“The zebra bit my cousin paul”
- anterior: temporal, zygomatic, buccal, & mandibular
- inferior: cervical
- posterior: posterior auricular
The vagus includes the
superior laryngeal nerve (internal & external branch)
Recurrent laryngeal nerve
The internal branch vs. external branch of the superior laryngeal nerve.
internal branch- sensory innervation to posterior epiglottis to vocal cord folds
external branch- motor innervation below the vocal cords
The recurrent laryngeal nerve provides
sensory innervation below the vocal cords & trachea
motor innervation to all intrinsic laryngeal muscles
-Right RLN loops under subclavian artery
L RLN loops under aorta & susceptible to injury
There is increased ______ in the head & neck
vascularity
Facial, head, & neck arteries include:
carotid (internal & external) facial maxillary superficial temporal deep temporal superior thyroid buccal middle meningeal
Facial, head & neck veins that are deep include
internal jugular
maxillary
vertebral
Facial head and neck veins that are superficial include
external jugular
superficial temporal
occipital
facial
Sharing of the airway requires
preparation
planning
communication
For ENT cases, preoperative airway assessment
is critical
a thorough history & extensive evaluation allows:
-deliberate approach to airway management
-need for additional equipment & assistance
-determine alternative approaches
Common considerations for ENT cases nclude:
true sharing of the airway with the surgeon- eye protection, tube placement must allow for surgical facilitation (down-sizing)
-head of bed often rotated 90 to 180 degrees- need for additional line & tubing length (HME device)
Arms tucked- second IV line, nerve monitoring
-precordial or esophageal stethoscope
Nerve monitoring requires
specialized ETT
short acting narcotics & lack of paralysis
ETT needs to be secured with
tape or suture to prevent extubation, disconnects & leaks
After turning the patient,
ALWAYS REASSESS
-oxygenation/anesthetic level- tube placement, breath sounds
IV access
Specialized ETT tubes include:
small diameter ETT- decreased ventilation & increased resistance; standard tubes may result limited cuff contact
Oral ring, Adair, & RAE tubes- allows for better surgical access
-armored and reinforced tubes- greater flexibility and resist kinking (not guaranteed)
-metal-impregnated- reduce occurrence of airway fire
-laryngeal mask airway (LMA)
Common drugs for ENT cases include
vasoactive drugs anticholinergics corticosteroids postoperative nausea & vomiting deliberate controlled hypotension
Vasoactive drugs include
epinephrine- causes vasoconstriction 1:200,000
cocaine- naturally occurring ester of benzoic acid
Combination of these drugs can result in: headaches, hypertension, tachycardia, & dysrhythmias
Local anesthetics that might be used include
cocaine 4%
lidocaine 2%
bupivacaine 0.25%
Anticholinergics may be used for
antisialogogue effects
reduce vagal tone- glycoyrolate preferred
Corticosteroids may be used to
reduce nausea & vomiting (given early)
inhibit production of prostaglandins reducing pain & edema
ENT surgeries associated with increased incidence of
PONV
particularly middle ear
Additional reasons for PONV with ENT surgery include
accumulation of blood in oropharynx & swallowed- throat pack, orogastric suctioning prior to extubation
multimodal approach to prevent/treat
Select techniques commonly used in ENT surgery include:
laser surgery
endoscopy
jet ventilation
foreign body aspiration
Deliberate controlled hypotension is a technique to
reduce blood loss in prolonged cases
reduce MAP to pre-determined limits of cerebral autoregulation (50-60 mmHg; within 20% of baseline)
-arterial line is required (not always)
-better operating conditions achieved when hypotension is achieved with B-blocker
Laser light beams are used for their
thermal effect- lasers have only one wavelength
Commonly used lasers in ENT are:
CO2- longer wavelength- shallow depth & precise
Nd:YAG (neodymium-doped yttrium aluminum garnett)- shorter wavelength- pass through superficial structures
Argon
Laser safety includes
warning signs outside the OR
eye protection- provider & patient, lens depends on laser being used
use lowest oxygen concentration possible (goal of <30%)
avoid nitrous oxide
fill ETT cuff with saline and/or methylene blue
laser “plume”
Most surgical fires occur during
head & neck surgery
due to combination of oxygen & laser use
laser penetrates ETT into oxygen rich environment- creates blowtorch effect
When an airway fire occurs, remove
ETT immediately and replace with a new tube
perform bronchoscopy
Prevention of airway fires includes
metal impregnated ETT saline filled ETT cuff use lowest FiO2 possible avoid nitrous oxide avoid paper drapes use water-based lubricants
Endoscopy procedures may include
panendoscopy, laryngoscopy, bronchoscopy, esophagoscopy (flexible or rigid scope), sinus surgery
Common pathology with endoscopy includes
foreign body aspiration
tumors/lesions
vocal cord dysfunction
Anesthetic considerations for endoscopy include:
manage brief periods of extreme stimulation- avoid patient movement- consider lidocaine, remifentanil, and esmolol to block sympathetic stimulation
short procedures- careful muscle relaxation
constantly sharing airway with surgeon- small cuffed ETT 5.0-6.0 mm for adult, intermittent apnea
Jet ventilation is
manual ventilation using hand valve or mechanical device
- inspiration is high velocity jet stream (60 psi)
- expiration is passive
With jet ventilation, if an airway mass lies above the level of gas delivery, there is an increased risk of
air trapping resulting in subcutaneous emphysema or pneumothorax
Jet ventilation may require
TIVA anesthesia
Jet ventilation is contraindicated in
full stomach, hiatal hernia, trauma
High frequency jet ventilation is used when
limited access to the airway
- done through a small needle, ETT, catheter or side port to a rigid bronchoscope
High frequency jet ventilation uses
low tidal volumes & high respiratory rates
Maintaining________ can be difficult in certain patient populations with high frequency jet ventilation.
oxygenation
Indications for sinus surgery includes
sinus obstruction (infection, polyps, or tumors) sinustomies
Surgical options for sinus surgery includes
endoscopic (FESS)
external
flouro
brain lab
Sinus surgery can be performed under
general anesthesia vs. MAC
-ETT vs. LMA (decreased risk of blood flowing in oropharynx)
Polyps associated with asthma & cystic fibrosis can result in
allergies
reactive airway
Goals with sinus surgery include to
decrease bleeding through mild hypotension, vasoconstrictor use, & deep anesthesia
Complications of sinus surgery include
dural puncture
Treatment for dural puncture includes
discontinue nitrous oxide (if using) ETCO2 25-30 mmHg mild hypotension place foley catheter consider mannitol 25-50 g/IV patch by surgeon
Sinus surgery can possibly indicate
deep extubation
would want to prevent coughing, bucking, and worsening of dural puncture if patient has one
The leading cause of accidental death among children <4 years is
foreign body aspiration
Most aspirated items are
food particles but can include beads, coins, pins, or parts of small toys
Signs & symptoms of foreign body aspiration includes
wheezing, coughing, aphonia, & cyanosis
The anesthetic management for foreign body aspiration depends on
size & location of object
If a foreign body is aspirated in the larynx, then use
laryngoscopy & removal with Magill forceps
If a foreign body is aspirated in the distal larynx or trachea, then use
rigid bronchoscopy with mouth guard to avoid injury
tracheal tears, & inadequate ventilation
Anesthetic considerations for foreign body aspiration includes:
inhalational induction with 100% oxygen- maintain spontaneous respiration
administer antisialagogue, H2 blocker, & prokinetic
coughing, bucking or straining must be avoided
be cognizant of full stomach- RSI- full airway obstruction- surgeon must be prepared to perform cricothyrotomy or tracheotomy
observe for vagal stimulation during procedure
Postoperative considerations for foreign body aspiration include
return of airway reflexes
edema possible for up to 24 hours post procedure–> Cuff leak?
supportive measures- racemic epinephrine, bronchodilators, steroids
