Anesthesia for Oropharyngeal Surgery

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Anesthesia for Oropharyngeal Surgery

• By
• Troy Johnson and
• Kevin Neary

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Outline

• Why ENT surgery
• ENT Anatomy
• Specialized equipment for ENT procedures
• RAE and MLT tubes
• Endoscopy
• Lasers
• Pharmacology considerations
• Anesthesia management for ENT procedures
• Le Fort fractures
• Case Presentation
• Tonsillectomy and Adnoidectomy
• Questions

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ENT surgery Special considerations

• Surgical procedure performed d/t anatomic
  structures are abnormal, distorted, or deviated
• Often involves sharing Airway w/ surgeon and
  positioning pt away from anesthetist
• Risk of bleeding from surgical site into airway
  and stomach
• Risk of laryngeal and pharyngeal post-op edema
  (upper air way obstruction)
• Potential for CN injuries d/t location of
  surgical sites
• Variety of different airway management techniques
  required for ENT surgeries
• Potential for Airway fires r/t Laser and cautery

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ENT Anatomy - Nose
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The Nose

• Function
• Warming, filtering, and providing humidity to the
  air taken in during inspiration
• Structures
• Sinuses Frontal, maxillary, and ethmoid
  hollow structures formed of low-density bone and
  are lined with a thin layer of mucous membranes
  susceptible to fractures secondary to facial
  trauma
• Turbinates highly vascular w/ 3 compartments
  superior, middle and inferior used to increase
  the surface area of the nasal cavities, aid in
  filtration and humidification of inspired gases
• Congestion of the mucosal veins in the turbinates
  cause swelling of the tissues decreasing the
  size of the nasal cavity and thus creating the
  feeling of congestion during respirations

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ENT Anatomy - Throat
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Pharynx

• Composed of the terminal end of the
• nasopharynx (extends to the soft palate)
• oropharynx (includes base of tongue, soft palate,
  uvula, and lymphatic structures tonsils)
• laryngopharynx (extending to C-6)
• Tonsils most sensitive area of oropharynx
  containing a generous blood supply from branches
  of the external carotid, maxillary, and facial
  arteries also within close proximity to facial
  and internal arteries
• Function
• Swallowing
• Passage of air breathing
• Modulator for the voice

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Swallowing reflex

• initiated by touch receptors in the pharynx as a
  bolus of food is pushed to the back of the mouth
  by the tongue.
• Pharyngeal swallow is co-ordinate by the
  swallowing center in the medulla oblongata and
  pons
• If this fails and the object goes through the
  trachea, then choking or pulmonary aspiration can
  occur
• Nerves mediating control of swallow reflex
• Superior laryngeal
• Recurrent laryngeal
• Glossopharyngeal

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ENT Anatomy Larynx
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Larynx

• Distal to Waldeyes ring (Ring of lymphoid
  tissue, formed by the lingual tonsil, palatine
  tonsils, and nasopharyngeal tonsils (also called
  adenoids)
• Forms connection between the oropharynx and the
  trachea
• 3 cartilage structures epiglottis, thyroid, and
  cricoid
• Primary function
• Vocalization and articulation
• Protection of airway and allows respiration
• adults vocal cords/ rima glottis is narrowest
  portion of larynx
• children cricoid ring narrowest portion until
  age 10 cuffed tubes recommended for child older
  than 8-10 to allow for better seal of airway,
  prevent subglottic edema, and reduce the
  incidence of postoperative airway compromise

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Sensory Nerves of the Airway
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Cranial Nerves of the Head and Neck

• CN VII - facial 5 branches
• 4 anterior temporal, zygomatic, buccal, and
  mandibular
• 1 inferior cervical
• 1 posterior posterior auricular

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Cranial Nerves of the Head and Neck

• CN V Trigeminal nerve 3 branches
• Ophthalmic
• Maxillary
• Mandibular
• all 3 divisions provide sensory and motor
  innervation (mastication and motor control of
  face) to the nose, sinuses, palate, and tongue

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• CN IX Glossopharyngeal
• Motor and sensory innervation for base of tongue
  and nasopharynx and oropharynx
• Elicits gag reflex during instrumentation of
  posterior pharynx and valecula

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Cranial Nerves of the Head and Neck

• CN X Vagus nerve
• Superior laryngeal (sensory input above cords),
  internal laryngeal (branch of superior) and
  recurrent laryngeal nerves (sensory and motor
  all muscles of larynx except cricothyroid muscle
  are branches of the vagus nerve

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ENT Anatomy - Ear
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Surgical Implications of Ear Surgery

• Maintain nerve preservation
• CN VII, IX, X, XI and XII
• Utilize short acting NDMRS in order to asses
  function of nerves early
• N2O effect on middle ear
• Control bleeding vasoconstrictors, pressure
• PONV

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Shared Airway Considerations - Positioning
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Specialized Equipment for ENT procedures

• Endotracheal tubes
• Microlaryngeal or Mallinckrodt ETT (MLT)
  specialized tube w/ small diameters allowing for
  an even distribution of the cuff over the trachea
  during inflation
• Right-angled endotracheal (RAE) tubes
  non-cuffed and cuffed types available for either
  oral or nasal intubation (good for cleft palate
  repair, tonsillectomy, uvoloplastopharyngoplasty
  nasal RAE for maxillofacial surgery
• Metal-impregnated tubes for use w/ laser surgery
  cuff is usually filled w/ saline to dampen or
  prevent ignition
• RAE tubes- preformed bend prevents the ETT from
  kinking the bend may be too distal or proximal
  for an pts airway allowing the tip to rest well
  below or above the carina

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Endoscopy

• Surgeries include
• panendoscopy combination of below endoscopic
  procedures
• laryngoscopy - used to visualize pharynx,
  hypopharynx, or larynx
• Microlaryngoscopy use of MLT tube
• esophagoscopy - visualize esophagus
• bronchoscopy visualize tracheobronchial tree
• Premedication w/ an antisialagogue to dry
  secretions and a full regimen of acid aspiration
  prophylaxis in aspiration prone pts may be
  indicated
• Large concern with shared airway space utilize
  MLT - some use intermittent apnea (repeatedly
  removing ETT to allow surgeon to work.

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Lasers

• Acronym light amplification by stimulated
  emission of radiation
• Standard light has a variety of wavelengths
  laser has only one
• Types
• CO2 most often used for operations around
  larynx shallow depth of burn and extreme
  precision -
• NdYAG shorter wavelength than CO2 laser -
  poorly absorbed by water but easily absorbed by
  Hgb and pigmented tissue capable of producing
  deep tissue penetration
• Argon Laser
• The shorter wavelength allows less absorption by
  water and therefore less tissue penetration
• Plume the smoke and vapors formed when tissues
  are cut by a laser can be deposited in lungs
• Potentially toxic when tissue vaporized by laser
  are malignancies or viral papilloma minimize
  hazard with efficient smoke evacuator (suction)
  and special masks for personnel

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General Safety Protocol for Surgical Lasers

• 1) Post warning signs outside any operating area
  WARNING LASER IN USE
• 2) Patients eyes should be protected with
  appropriate colored glasses and/or wet gauze
• 3)Matte-finish (black) surgical instruments
  reduce beam reflection and dispersion
• 4) Use the lowest concentration of oxygen
  possible
• 5) Avoid using N2O since it supports combustion
• 6) Lasers should be placed in STANDBY mode when
  not in use
• 7) Use an endotracheal tube specifically prepared
  for use with lasers
• 8) Inflate cuff of laser tube with normal saline
• 9) All adjacent tissues should be shielded by wet
  gauze to prevent damage by reflected beams
• 10) Plume should be suctioned and evacuated from
  the surgical field

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Steps to Reduce Airway Fire

• 1) Use lowest concentration of oxygen appropriate
  for particular pt
• 2) avoid paper surgical drapes
• 3) water based rather than oil-based lubricants
• 4) appropriate ETTS (laser)
• 5) NO N20

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Protocol for Airway Fire

• Disconnect the anesthesia delivery circuit from
  the tracheal tube and cease ventilation of the
  patients lungs
• Extubate the trachea
• Extinguish the removed flaming material with
  water
• Ventilate the patients lungs with oxygen by
  facemask and reintubate the trachea

• Perform rigid bronchoscopy to assess airway
  damage and remove debris
• Assess the oropharynx and face
• Obtain a chest x-ray
• Consider bronchial lavage, corticosteroids, and
  antibiotics

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ENT Anesthetic Implications

• Possessing a thorough knowledge of the airway
  anatomy and function
• Selecting appropriate techniques and approach for
  the airway management
• Preventing and managing potential airway
  complications
• Producing profound selective muscle relaxation
  during periods of extreme stimulation
• Maintaining cardiovascular stability during
  periods of potent surgical stimulation

• 6. Omitting neuromuscular relaxation for
  surgical procedures that require isolation of
  nerves
• 7. Preventing and containing an endotrachial
  tube fire
• 8. Minimizing intraoperative and postoperative
  blood loss
• 9. Preventing adverse respiratory and cardiac
  responses resulting from manipulation of the
  carotid sinus and body
• 10. Taking the appropriate postoperative
  measures to prevent and treat postsurgical airway
  obstruction
• 11. Avoiding or limiting the use of nitrous
  oxide during tympanoplasty or other closed-space
  grafting

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Pharmacology with ENT Surgeries

• Local Anesthetics Amides mostly used
• Be aware of physiologic changes w/ acidosis,
  infection and hyperthermia
• Vasoactive drugs
• Cocaine (ester) 4-10 solutions used in more than
  50 of ENT procedures hydrolyzed by plasma
  cholinesterase and produces vasocnstriction by
  blocking catecholamine reuptake resulting in
  vasoconstriction and shrinking of mucosa
• Epinephrine also used
• Anticholinergics
• Premedication will reduce vagal tone, secretions
  and increases bronchodilation
• Caution with closed angle glaucoma
• Corticosteroids
• Can be administered preoperatively and
  intraoperatively to decrease laryngeal edema
  formation, reduce nausea and vomiting, and
  prolong the analgesic effects of local
  anesthetics.
• Administer as early as possible in order to reach
  peak effect prior to initiating surgery
• can create sufficient immunosppression to mask
  inflammation or infection

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PONV

• ENT procedures particularly of the middle ear are
  associated with a high incidence of PONV
• Need to counter both central chemoreceptor
  trigger zone (CTZ) and peripheral receptors in
  the gastric area, eye, and middle ear
• Combination of drugs, fluid balance, and limiting
  exposure to anesthetics producing PONV is needed.
• 5-HT3 (Zofran)
• Corticosteroids (decadron)

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Le Fort Fractures

• Le Fort I a horizontal fracture of the maxilla,
  extending from the floor of the nose and hard
  palate through the nasal septum and through the
  pterygoid plates posteriorly.
• Le Fort II a triangular fracture running from
  the bridge of the nose through the medial and
  inferior wall of the orbit, beneath the zygoma
  and through the lateral wall of the maxilla and
  pterygoid plates.
• Le Fort III this fracture totally separates the
  midfacial skeleton from the cranial base,
  traversing the root of the nose, the ethmoid bone
  and eye orbits and sphenopalatine fossa.

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Le Fort Fractures
I oral or nasal
intubation ok II
contraindicated for nasal intubation
III contraindicated for nasal
intubation Attempts to pass an endotrachial tube
or nasogastric tube trough the nares could lead
to intracranial placement, bringing contaminated
material into the subarachnoid space and causing
meningitis or damage to the brain itself
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Le Fort I
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Le Fort II
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Le Fort III
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Case Presentation - SDS TA

• Male 5y.o. patient Hypertrophied tonsils
• NKDA normal age appropriate healthy
• No history of familial anesthesia problems
• Patients weight 25 kg
• Room setup
• 3cc syringe with 0.4mg Atropine and 20 mg
  Anectine with IM needle
• 5cc syringe with 4mls 0.1 mg/ml Atropine
• 250ml or 500ml bag of NS with microdrip
• Fentanyl in 10cc syringe diluted to 10mcg/ml
• propofol in 10cc syringe

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Case Presentation - SDS TA

• 20mg Decadron and dose of Zofran
• various size RAE tubes, blades, and masks
• IV supplies 20g,22g,24g, kerlex and kling
• MONITORS
• Pulse Oximeter, NBP, EKG, Precordial Stethoscope,
  Temperature Strip, Gas Monitor

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Case Presentation - SDS TA

• INDUCTION MASK PART I
• Place patient on OR table apply pulse ox (if
  able)
• Turn on 8 Sevo, N2O 6L,O2 2L
• Apply mask to face pt will breathe down
• Insert oral airway-with 2 breaths
• Once ready to start IV TURN OFF N2O

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Case Presentation - SDS TA

• INDUCTION IV PART II
• Peripheral IV started, check EtO2
• Fentanyl 1-2mcg/kg IV
• Propofol 2.5-3.5mg/kg IV
• Take over pts respirations and drive down pCO2,
  decrease Sevo to 3 or 4 or change to Iso

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Case Presentation - SDS TA

• INTUBATION
• Once ETO2 is high and ETCO2 is low, time to DVLxT
• Use ETT with cuff, if cords are open insert tube,
  if not use paralytic ROC or SUCC
• Once ETT is in and placement verified, secure
  tube and get ready to turn table
• Once table is turned and circuit reconnected
  decrease O2 delivery as quickly as possible

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Case Presentation - SDS TA

• MANAGEMENT
• Depending whether attending or resident is doing
  the procedure is how fast you will need to get
  the patient back breathing
• Maintain M.A.C. with either Sevo or Iso
• Allow ETCO2 to increase
• May give more Fentanyl 10mcg x1

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Case Presentation - SDS TA

• EMERGENCE
• Always have help if available
• Patient back breathing, good rate and rhythm
• Gentle oral suctioning, not so much you cause
  bleeding, observe if tonsil bleeding
• Turn off agent, oxygenate pt well
• Extubate patient either deep or light, not in
  between
• Apply positive pressure until patient resumes
  regular rate and rhythm

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Case Presentation - SDS TA

• LARYNGOSPASM
• Do you have a plan?
• This is an emergency! Pediatrics will desat
  quickly!
• Early Signs and Symptoms
• Tracheal Tug
• Paradoxical movement of chest and abdomen
• Late Signs and Symptoms
• Desaturation
• Bradycardia
• Cyanosis

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Case Presentation - SDS TA

• LARYNGOSPASM
• Crank down pop-off two hand mask grab and jaw
  lift with 100 Oxygen
• Pt desats IV Propofol or Anectine, continue
  positive pressure
• Laryngospasm breaks

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Questions

• What are the afferent and efferent nerves
  responsible for a laryngospasm?
• A) Recurrent laryngeal nerve and external branch
  of the superior laryngeal nerve
• B) Cricothyroids and the vagus nerve
• C) Internal branch of the superior laryngeal
  nerve and the external branch of the SLN
• D) Recurrent laryngeal nerve and the cricothyroids

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Answer C

• The internal branch of the superior laryngeal
  nerve which is also a branch of the vagus
  provides afferent input above the cords
• The external branch of the superior laryngeal
  nerve provides the motor (efferent) innervation
  to the cricothyroid muscles which are involved
  in laryngospasm
• The recurrent laryngeal nerve which is also a
  branch of the vagus provide sensation below the
  cords

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Question

• The most commonly damaged nerve during a
  thyroidectomy is ?
• Superior laryngeal nerve, internal branch
• Superior laryngeal nerve, external branch
• Recurrent laryngeal nerve
• Glossopharyngeal nerve

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Answer C

• Recurrent Laryngeal nerve d/t surgical position
  of thyroid and recurrent laryngeal nerve
  usually unilateral damage
• Injury charcterized by hoarseness and a paralyzed
  cord that assumes an intermediate position

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Question

• Appropriate measures for an airway fire are
• A) Disconnect the anesthesia delivery circuit
  from the tracheal tube and cease ventilation of
  the patients lungs
• B) Extubate the trachea and extinguish the
  removed flaming material with water
• C) Ventilate the patients lungs with oxygen by
  facemask and reintubate the trachea
• D) Perform rigid bronchoscopy to assess airway
  damage and remove debris and Consider bronchial
  lavage, corticosteroids, and antibiotics
• E) All of the above

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Answer E

• All of the choices are part of the airway fire
  protocol

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• Following emergence and extubation, a patient who
  has undergone tonsillectomy should be transferred
  to the recovery area
• with the throat packs securely in place
• with the head of the bed elevated 30 degrees
• In semiprone position with the head down
• Supine with the stretcher in reverse
  trendelenburg position

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• Following emergence from a tonsillectomy, the
  patient should be placed in 'tonsillar' position
  which consists of lateral or semiprone position
  with the head down to decrease the risk of
  aspiration of blood.

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• Which surgery would you expect to require the
  greatest degree of postoperative pain control?
• A. Tonsillectomy
• B. Adenoidectomy
• C. Myringotomy
• D. Bronchosopy

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Answer A

• In order from least amount of expected
  postoperative pain to the greatest is myringotomy
  (pain score of 1-3 on a scale of 1-10),
  bronchoscopy (pain score 3-4), adenoidectomy
  (pain score 3-5), and tonsillectomy (pain score
  6-9).

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• Patients with cardiac valvular disorders
  undergoing tonsillectomy are at risk for
  endocarditis from chronic tonsillar infection by
• A. Staphlococcal organisms
• B. Streptococcal organisms
• C. Cryptococcal organisms
• D. Diplococcal organisms

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Answer B

• Chronic tonsillar infection places the patient
  with cardiac valvular disease at risk for
  endocarditis due to chronic streptococcal
  bacteremia