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Flashcards in ENT II Deck (45)
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1

What is the goal for ENT anesthesia?

What are the factors affecting airway safety?

  • 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

2

What are the general principles of ENT anesthesia?

(10)

  • 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

3

What does pre-operative stridor imply?

airway diameter < 4-5 mm

(nml is about 10 mm)

4

Why are anticholinergics used in airway surgery?

Corticosteroids?

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

5

Why might PONV be worse with airway surgery?

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

  • 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)

6

What are some post-op considerations for airway surgery?

  • 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

7

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

What are the advantages and disadvantages?

  • 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

8

How is the closed system with cuffed ETT done?

  • 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

9

What are the open systems?

What are the advantages and disadvantages?

  • 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.

10

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

  • 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

11

How is the open system Jet ventilation technique done?

  • **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

12

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

  • 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

13

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

  • 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

14

How is adequacy of jet ventilation assessed?

What are complications of jet ventilation?

  • 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

15

How are lasers used in Airway surgery?

Advantages?

What type is most common? Why?

  • 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

16

What are the hazards of using lasers in airway surgery?

  • 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

17

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

  • 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

18

What are anesthetic consdierations for laser airway surgery?

  • 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

19

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

  • 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

20

How is a bronchoscopy done?

  • 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

21

Tonsillectomy:

Indication

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

22

Tonsillectomy:

Pre-op

Induction

  • 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

23

Tonsillectomy:

maintenance

emergence

Airway

  • 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

24

Anesthetic management of the bleeding tonsil

  • 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

25

Anesthesia for foreign body aspiration

  • 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

26

Epiglottitis:

typical presentation

management

  • 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

27

Stridor:

symptoms

management

  • 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

28

What are some complications of functional endoscopic sinus surgery?

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

29

Nasal surgery:

preop

airway managment

  • 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

30

What can be used for nasal vasoconstriction?

  • 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)