ENT II

Question 1

What is the goal for ENT anesthesia?

What are the factors affecting airway safety?

Answer 1

• The provision of a clear, free, and unobstructed airway is the principal concern for all ENT procedures
• Factors affecting airway safety:
  
  • patient factors
  • remote surgery
  • surgical factors
  • shared airway

Question 2

What are the general principles of ENT anesthesia?

(10)

Answer 2

• simple
• provide complete control of the airway with no risk of aspiration
• control ventilation with adequate oxygenation and CO2 removal
• provide smooth induction and maintenance of anesthesia
• provide a clear, motionless surgical field
• free of secretions
• not impose time restrictions on the surgeon
• not be associated with any risk ofairway fire or CV instability
• allow safe emergence with no coughing, bucking, breath holding, laryngospasm
• produce a pain-free, comfortable, alert pt at the end

Question 3

What does pre-operative stridor imply?

Answer 3

airway diameter < 4-5 mm

(nml is about 10 mm)

Question 4

Why are anticholinergics used in airway surgery?

Corticosteroids?

Answer 4

• Anticholinergics
  
  • reduces vagal tone
  • reduces secretions
  • increases bronchodilation
• Corticosteroids
  
  • decrease edema formation
  • reduce nausea and vomiting
  • prolong analgesic effects of LA

Question 5

Why might PONV be worse with airway surgery?

Why might you want an A-line in an airway surgery?

Answer 5

• blood in stomach
  
  • throat pack used to prevent this, make sure it is removed before you extubate.
• A-line for deliberate controlled hypotension (MAP 60-70)

Question 6

What are some post-op considerations for airway surgery?

Answer 6

• Have head up to decrease edema
• observe for bleeding and edema
• administer humidified oxygen
• watch for pneumothorax
  
  • venturi effect sucks in surrounding air
• watch for respiratory failure
• steroids and racemic epi mist can help control laryngeal edema

Question 7

What is the closed system technique that can be used for airway surgery?

What are the advantages and disadvantages?

Answer 7

• Uses smaller sized (4-5mm) cuffed ETT
• Advantage:
  
  • routine technique
  • protection of lower airway
  • control of airway
  • control of ventilation
  • minimal pollution of VA
• Disadvantages:
  
  • Surgical access and visibility limited
  • high ventilation pressures needed with small ETT tubes
  • vocal cord damage with intubation
  • Risk of laser airway fire

Question 8

How is the closed system with cuffed ETT done?

Answer 8

• Small ETT 4-5 mm
  
  • Microlaryngoscopy tube-long, small tube with high-volume, low-pressure cuffs
  • Laser tubes- metal, fire resistant tube
    
    • can have no cuff or double cuff
• Be sure to prevent extubation, disconnects, and leaks
• Assess ventilation continually
  
  • observe chest movement, auscultation, pulse-ox, ETCO2, blood gas analysis
• Orchestrate turning

Question 9

What are the open systems?

What are the advantages and disadvantages?

Answer 9

• Open systems-
  
  • spontaneous ventilation and insufflation techniques
  • muscle paralysis and jet ventilation
• Advantages:
  
  • Laser safety
  • reduced risk of ETT-related trauma
  • complete laryngeal visualization
• Disadvantages:
  
  • unprotected lower airway
  • lack of control of ventilation
  • operating room polution
  • specialized knowledge, equipment, and experience required.

Question 10

How is the spontaneous ventilation with insufflation technique of the open system done?

Answer 10

• Pt remains spontaneously breathing with natural airway
• Anesthetic gases insufflated via:
  
  • a small catheter in nasopharynx and above laryngeal opening
  • tracheal tube cut short and placed in nasopharynx emerging just beyond soft palate
  • nasopharyngeal airway
  • side-arm channel of laryngoscope or bronchoscope

Question 11

How is the open system Jet ventilation technique done?

Answer 11

• **pt is paralyzed and apneic
• Subglottic jet ventilation by:
  
  • jetting needle attached to a laryngoscope or bronchoscope
  • transtracheal catheter thru cricothyroid membrane
  • small-diameter (2-3 mm), cuffed/uncuffed ETT specifically designed for jet ventilation
• High frequency (>1 Hz, 60 breaths/min) with ventilator rates 100-150/min
  
  • automated high-frequency ventilators with alarms and automatic interruption if pressure limits are reached

Question 12

What is the difference between hand triggered jet ventilation and using an oscillator?

Answer 12

• Hand-triggered devices-
  
  • usually low-frequency jet ventilation (8-10 breaths per min) to allow adequate time for exhalation via passive recoil of lung and chest wall
  • prevents air-trapping and build-up of pressure in small airways
  • Ventilate at low pressures of 30-50psi. [least amount possible]
  • Inspiration is 1.5secs, expiration 6secs
• High-frequency jet ventilators (oscillatory ventilation)
  
  • jets gas at 1-10 Hz
  • both inspiration and expiration are active
  • driving pressure, frequency, inspiratory time, and composition of jet gas can
    be adjusted
  • RR up to 100bpm

Question 13

What is the process for doing an anesthetic with Jet ventilation?

Answer 13

• Preoxygenation
• IV induction
• NDMR
• laryngoscopy
• topical anesthesia
• LMA or ETT inserted
• Ventilation with 100% FiO2 until surgeon is ready to site the rigid laryngoscope with jetting needle
• Maintenance anesthesia with propofol and remi infusion
• At end of surgery, LMA reinserted
• NDMR antagonized
• Anesthetic infusions stopped
• smooth awakening with LMA/ETT removal

Question 14

How is adequacy of jet ventilation assessed?

What are complications of jet ventilation?

Answer 14

• Assess it continuously! by:
  
  • observation of chest movements
  • O2 sats
  • listening for changes to the sound during air entrainment and exhalation
  • observation of airway patency
• Complications of jet ventilation:
  
  • crepitus
  • pneumothorax
  • barotrauma
  • gastric distension

Question 15

How are lasers used in Airway surgery?

Advantages?

What type is most common? Why?

Answer 15

• Laser light beams are used for their thermal effects to cut, coagulate, and vaporize tissues
• lasers have one wavelength, moving in the same direction and its beam is parallel
• Laser light emits a small amount of radiation
• Advantages:
  
  • very precise
  • minimal edema
  • minimal bleeding
• CO2 laser is common in Airway d/t shallow depth of burn and extreme precision
  
  • Long wavelength absorbed by surface tissues

Question 16

What are the hazards of using lasers in airway surgery?

Answer 16

• Atmospheric contamination
  
  • plume of smoke and fine particulates
  • deposition in lungs
  • leads to PNA, inflammation, viral infections
• Perforation of a vessel or structure
• Embolism
• Inappropriate energy transfer
  
  • reflection and scatter of beams can cause immediate or delayed injury to normal tissue, especially the eyes
  • CO2 reacts at surface causing corneal damage
  • Nd: YAG and argon gas pass through the cornea to the retina
  • tape eyes closed and cover with wet gauze
  • PROTECT YOUR OWN EYES!
• Fires!
  
  • Lasers produce intense heat
  • CO2 laser can penetrate ETT and ignite fire
  • usually subglottic, epiglottic and orpharyngeal areas are involved in fire
  • smoke inhalation

Question 17

What are the strategies used to reduce the incidence of airway fire?

Answer 17

• Reduce flammability of ETT
• remove flammable materials from the airway by using jet ventilation or intermittent extubation with or without apnea
• reduce available oxygen (best is 0.3 FiO2)
• avoid paper drapes and oil-based lubricants, caution with alcohol prep solutions

Question 18

What are anesthetic consdierations for laser airway surgery?

Answer 18

• Surgical visibility vs airway control
  
  • GETA with laser ETT and methylene blue or NS in the cuff
  • Insufflation techniques through nasal tube
  • Jet ventilation thru jeting arm of scope
  • apneic technique
• lowest possible FiO2
• Protect yees with laer safety eyewear or saline moistened pads and laser eye shields
• face and neck should have wet gauze over them
• have NS readily available to douse fire

Question 19

What should you do in the even of an airway fire?

Answer 19

• Remove burning ETT and/or other material from airway
• stop ventilation
• D/C oxygen
• flush the pharynx with cold saline
• mask with 100% O2
• laryngoscopy and bronchoscopy to assess damage
• administer:
  
  • humidified gas
  • steroids
  • abx
• may need to reintubate or even trach and control ventilation
• check ABGs, SpO2, CXR

Question 20

How is a bronchoscopy done?

Answer 20

• GETA or jet ventilation
• ETT 8.0 or larger
• ensure immobility
• possible antisialogogue
• TIVA has advantages of IA
• short-acting drugs
• adjust ventilation rates with manipulation of scope

Question 21

Tonsillectomy:

Indication

Answer 21

• Indicated for severe infection and hypertrophy of tonsillar bed
• Associated with OSA and URIs

Question 22

Tonsillectomy:

Pre-op

Induction

Answer 22

• Pre-op:
  
  • evaluate loose teeth (age 4-7)
  • Have they had recent URI?
  • Recent abx use?
  • OSA?
• Induction
  
  • possible stridor or obstruction
  • GA with ETT or LMA?
    
    • oral rae or reinforced

Question 23

Tonsillectomy:

maintenance

emergence

Airway

Answer 23

• Maintenance:
  
  • supine with table turned 45 degrees
  • deep anesthetic level
  • hydrate well
  • short-acting narcotics
• Emergence
  
  • deep vs awake
• Airway
  
  • High incidence of laryngospasm and stridor
  • lidocaine
  • side-lying with head slightly down on extubation
  • PONV prophylaxis
  • pain control steroids for edema

Question 24

Anesthetic management of the bleeding tonsil

Answer 24

• Usually occurs 7-10 days after surgery
• determine the extent of blood loss
  
  • check hgb, hct, coags, T&C for blood
• hydrate well and do not premedicate
• potential for hypovolemia, full stomack, and airway obstruction
• potential for difficult airway
• RSI with head down to prevent aspiration of blood
• place NG tube and extubate AWAKE

Question 25

Anesthesia for foreign body aspiration

Answer 25

• leading cause of accidental deaths in peds pts under 1 yr
• Do not want to dislodge the foreign body or push it distally into airway
• no premeds
• anticholinergics to dry secretions and prevent pradycardia
• sitting position
• gentle mask inhalational induction with spontaneous respirations
  
  • no cricoid or positive pressure ventilation
• surgeon should be prepared to perform tracheostomy or cricothyrotomy
• racemic epi post procedure for swelling
• dexamethasone, abx, O2 post-op

Question 26

Epiglottitis:

typical presentation

management

Answer 26

• Typical presentation:
  
  • rapid, sudden sore throat
  • fever
  • dysphagia
  • drooling
  • open mouth
  • stridor
  • resp distress
• Management:
  
  • Do not attempt instrumenation without surgeon ready for emergency tracheostomy
  • expect difficult intubation
  • mask induction, spontaneous vent
  • smaller ETT
  • intubated to ICU 24-72 hours with abx and sedated

Question 27

Stridor:

symptoms

management

Answer 27

• Occurs when airway diameter in adult is <4-5 mm
• Sx:
  
  • noisy, high pitched, predominantly inspiratory sound from turbulent airflow from upper airway obstruction
• Management:
  
  • 100% O2 facemask
  • HOB up
  • nebulized racemic epi 1 mg of 1:1,000 solution in 5 ml of NS, q 30 minutes
  • dexamethasone 0.1 mg/kg IV q 6 hours
  • Helium

Question 28

What are some complications of functional endoscopic sinus surgery?

Answer 28

• VAE
• trauma to eyes
• CSF leak
• excess bleeding
• focal neurologic deficit
• death

Question 29

Nasal surgery:

preop

airway managment

Answer 29

• Pre-op
  
  • evaluate for OSA
  • evaluate for nasal polyps
    
    • can develop NSAID sensitivity and asthma with nasal polyps; can cause life threatening bronchospasm
• Airway management
  
  • GETA
  • flexible LMA
• MAC

Question 30

What can be used for nasal vasoconstriction?

Answer 30

• Cocaine- LA with vasoconstriction
  
  • increased doses cause tachycardia, HTN, myocardial irritability and depression
  • Onset 1 min, peak 5 min, duration 30-60 min
  • usually 4% topical solution
  • max dose of cocaine 200 mg
• Phenylephrine- alone or w/lidocaine
  
  • initial dose should not exceed 0.5 mg
  • may cause severe HTN
  • avoid BB and CCB d/t myocardial depression and pulm edema
• Epinephrine
  
  • safe total dose of 1.5 mcg/kg (200 µg)

Question 31

Anesthetic management for endoscopic sinus surgery:

maintenance

emergence

Answer 31

• Maintenance:
  
  • HOB slightly elevated
  • deliberate hypotension
  • short-acting drugs
• Emergence
  
  • remove throat pack
  • careful suctioning
  • gastric suctioning
  • awake extubation to protect airway or deep extubation to avoid coughing, bucking
  • PONV prophylaxis

Question 32

What are the four major issues with ear surgeries?

Answer 32

• Nerver preservation
  
  • CN 7, 9, 10, 11, 12
• the effect of nitrous oxide on the middle ear
• control of bleeding
• PONV

Question 33

Myringotomy and tube insertion:

indication

surgery

anesthesia

Answer 33

• Indication: middle ear inflammation and effusion (otitis media)
• Surgery- incision in tympanic membrane and insertion of pressure-equalizing tubes
• Anesthesia
  
  • kids lack cooperation
  • frequently mask inhalation anesthesia
  • may give pre-op PO versed and PR tylenol

Question 34

What are the different surgeries of the middle ear?

Answer 34

• Tympanoplasty- for perforated tympanic membrane
• Stapedectomy- removing the stapes bone and replacing it with a micro prosthesis
• Mastoidectomy- to remove an infected portion of the bone or to remove a cholesteatoma or a skin cyst in the ear
• Acoustic neuromas- removal of a vestibular schwannoma (benign tumor of the myelinating schwann cells of the vestibulocochlear nerve)

Question 35

Anesthesia for ear surgery

Answer 35

• Patient understanding and cooperation are vital to prevent sudden movement at critical stages of surgery
• External ear- LA with light sedation (cooperative pt)
• Middle or inner ear- GA
• *airway access is limited during these procedures
  
  • Watch head positioning
  • LMA vs GETA
    
    • Oral rae
    • reinforced or armored tracheal tube
    • flexible LMA
    • Proseal LMA

Question 36

Anesthesia for ear surgery:

maintenance

emergence

Answer 36

• Maintenance
  
  • might do facial nerve monitoring- no NDMR
  • N2O- use caution with tympanic grafts
  • Limit bleeding
    
    • head-up position
    • smooth, balanced anesthetic w/ good analgesia
    • deliberate hypotension (MAP 50-60)
    • keep track of epi doses
• Emergence
  
  • Very high incidence of NV
    
    • prophylaxis
    • hydrate
  • Smooth emergence

Question 37

What are the different types of LeFort fractures?

Answer 37

1. Transverse fx through floor of maxillary sinuses (only palate moves)
2. Fracture through maxillary sinuses (pyramidal fx)
3. Fracture through orbits (craniofacial dysjunction)

Question 38

Anesthetic managment of LeFort fx

Answer 38

• LeFort I fx- may be intubated orally or nasally usually without difficulty
• LeFort II and III fx
  
  • cranial cavity open and dural tear
  • CSF in nose, blood behind tympanic membrane (racoon eyes are signs of fx and possible passage into the cranial cavity)
  • assess cervical spine stability, subdural hematoma, pneumothorax, intra-abdominal bleed
  • Caution with Nasal intubation
  • may need trach unler LA or awake oral intubation
  • expect blood loss and be prepared
  • NO access to oropharynx post procedure d/t wiring

Question 39

Pre-op managment of neck dissection

Induction of neck dissection pt

Answer 39

• Pre-op
  
  • emaciated, dehydrated and anemic pts
  • assess difficult airway r/t tumor location and size, radiation therapy , and past resections
  • prepare for possible changes with flap reconstruction
  • blood available
• Induction
  
  • GETA
  • surgical trach at the beginning or during the procedure with J shaped laryngectomy tube

Question 40

Anesthetic management of neck dissection

maintenance

emergence

Answer 40

• Maintenance
  
  • Aline and CVP?
  • good IV access
  • deliberate hypotension (SBP 85-90)
  • Head up tilt 10-15%
  • watch for VAE and carotid sinus manipulation
  • ask about surgical nerve stimulator and NDMR
• Emergence
  
  • new trach irritating and causes coughing
    
    • humidification, regular sxn, head up
  • pain control
  • PONV prophylaxis
  • watch for trauma to R stellate ganlion and cervical ANS

Question 41

Thyroidectomy:

indications

complications

Answer 41

• Removal for cancer and goiter
• Complications
  
  • removal of parathyroid gland
  • tracheal compression
  • damage to laryngeal nerves
    
    • RLN, extension of SLN

Question 42

Anesthesia management for thyroidectomy:

Pre-op

Induction

Answer 42

• Pre-op
  
  • want euthyroid
  • airway assessment
• Induction
  
  • Blunt SNS responses
  • EMG ETT
  • LMA
    
    • advantage- spontaneously breathing pt can assess vocal cord funtion in real time
    • disadvantage- limited and possible difficult access to airway

Question 43

Thyroidectomy

Maintenance

emergence

Post op complications

Answer 43

• maintenance:
  
  • no muscle relaxation d/t surgical nere stimulation
  • no esophageal stethescope or NGT
  • monitor for thyroid storm, compression of trachea
• Emergence
  
  • smooth
• Post op complications
  
  • hematoma–airway obstruction
  • RLN damage
    
    • unilateral- hoarseness
    • bilateral- vocal cord paralysis and airway obstruction
  • SLN damage
    
    • voice tires easily, high risk of aspiration
  • Hypocalcemia from inadvertant removal of parathyroid glands
    
    • usually develops within first 72 hours
    • perioral numbness and tingling, paresthesia, mental status changes
    • laryngeal stridor and progressing to laryngospasm

Question 44

Anesthetic management for tracheostomy

induction

Answer 44

• Awake with local- pt must be cooperative
  
  • technically challenging for surgeon, not ideal
• GA (ideal)
  
  • ETT, mask, LMA
  • avoid muscle relaxation

Question 45

Anesthetic management for tracheostomy

maintenance

emergence

Answer 45

• maintenance
  
  • watch FiO2 and use of cautery
  • IV lidocaine prior to trach insertion
  • pulling ETT technique
  • confirm ETCO2, BBS, O2 sat, airway pressures
• Emergence
  
  • fresh stoma irritating
  • humidification HOB up, O2
  • CXR
  • tracheostomy matures in 5-7 days