anesthesia for ENT surgery

1. Anaesthesia for ENT surgery
Nigussie S.
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3/19/2024

2. Anaesthesia for ENT surgery
Outline
 Introduction
 Preoperative airway evaluation
 Anaesthesia for specific ear, nose and throat
surgery
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3.  Anesthesia for ENT surgery encompasses a range of operations
varying in duration, severity, and complexity
 Airway problems are the major concern in ENT surgery
 Surgical procedures for ENT will challenge the creativity and
skills of the anesthetist.
 Some of the challenges include:-
—Diagnosis alterations in a patient's airway created by
infection, tumor, trauma, or congenital defect.
—Establishing and maintaining the airway in a patient whose
anatomy has been distorted
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4. Challenges cont..
—Creating a shared operative field
—Selecting appropriate anesthetic drugs compatible with the surgical procedure
—Defining the appropriate moment for extubating the trachea of the postoperative
patient.
 Cooperation & communication b/n surgeon & anaesthetist are more important during
ENT surgery
—The surgeon and anaesthetist should plan together preoperatively
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5.  Significant obstruction and anatomic distortion may be present in a patient with
minimal evidence of disease because clinically evident upper airway
obstruction is a late sign.
 Radiologic evaluation may provide insight into airway anatomy to develop
airway management plan
—It is a most unwelcome experience for the anaesthetist to discover a large,
unexpected, obstructed upper airway at the time of attempted tracheal
intubation
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6.  Patients with preoperative airway obstruction usually present for surgery either to
establish the diagnosis or to relieve the obstruction
 Evaluation of the location, size, extent, and mobility of any lesion is required.
 The effects on laryngeal function and airway patency must also be investigated
 Previous anaesthetic and surgical findings are useful, though tumours may grow
rapidly and radiotherapy can change tumour size, appearance, and mobility.
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7.  Factors affecting airway safety and maintenance may be
classified into the following four groups:
1. Patient factors- distorted upper airway anatomy or
airway obstruction.
2. Remote surgery- use of surgical microscopy
3. Surgical factors- positioning, bleeding, instruments
4. Shared airway- surgery of the glottis, subglottis, and
trachea
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8. Anaesthesia for specific ENT
surgery
E-N-T-
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9. Anaesthesia for ear surgery
 Ear procedures can be divided into
—external
—middle ear
—mastoid
—inner ear procedures.
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10. External Ear
• involve removal of simple lesions, foreign bodies in the external auditory
canal, preauricular abnormalities, and complex reconstruction of the
external auditory canal.
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11. Anesthesia for Ear Surgery…
Middle Ear and Mastoid
—In children, otitis media can result in middle ear effusions
with hearing loss and may require repeated procedures for
fluid drainage and tube placement to allow ventilation of
the middle ear.
—Chronic infections can lead to a perforation of the
tympanic membrane and damage to the middle ear ossicles
spreading into the mastoid cavity, inner ear, lateral sinus,
meninges, and brain.
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12. Anesthesia for Ear Surgery
—Chronic otitis media can result in temporomandibular
joint ankylosis.
—Frequently have accompanying recurrent URT infection.
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13. Anesthesia for Ear Surgery
Middle ear surgery can be done
 Local Anesthesia
 Nerve Block
 General Anesthesia
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14. Local Anaesthesia
 Local anesthesia with or without sedation can be undertaken safely in
suitable patients.
 The choice of LA with or without sedation or GA depends on patient
cooperation, duration of procedure, patient preference, patient
understanding, and surgical preference.
 Simple external ear and some middle ear procedures involving the
tympanic membrane and stapes are suitable for LA with or without sedation
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15. Nerve Block
 The sensory nerve supply of the ear comes from
—the auriculotemporal nerve,
—greater auricular nerve,
—auricular branch of the valgus nerve, and tympanic nerve.
 Local anesthesia involves infiltration of the anterior and posterior external
meatal wall blocking the auriculotemporal and greater auricular nerve.
 Infiltration through an aural speculum blocks the auricular branch of the
vagus, and topical infiltration of LA on the tympanic membrane blocks the
tympanic nerve.
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16. General anesthesia
 Nearly all surgery on the external, middle, and internal ear requires
the use of an operating microscope,
—where movements, coughing, and straining are greatly
magnified.
—Access to the airway during the procedure is limited
 thorough preoperative assessment, with specific attention paid to
hypertension or other cardiovascular disease
— which contraindicates or limits attempts to control blood pressure
intraoperatively.
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17. General Anaesthesia
 Airway—Facemask, Tracheal Tube, or Laryngeal Mask Airway
 Preference depends on
— the duration of surgery,
—experience of the anesthesiologist
—patient factors
—Availability of suitable equipment
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18. Ear cont..
.
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19. Middle ear surgery
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20. Middle ear
• Myringoplasty involves the closure of a persistent perforation in the tympanic
membrane using a graft of tissue from the temporalis muscle and fascia.
• Tympanoplasty involves a more extensive repair to the tympanic membrane
and reconstruction of the damaged underlying ossicular chain.
• Stapedectomy involves the removal of a damaged stapes resulting in a
conductive hearing loss and replacement by a prosthetic implant.
• Mastoidectomy- removal of infected mastoid bone
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21. Middle ear …
 Myringotomy
• is incision of the tympanic membrane to drain pus.
• can be done in out patient base and relatively short procedure.
• Means as aday case surgery
• anesthesia may be effectively accomplished with a IAA and oxygen.
Myringotomy and tube insertion
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22. Anaesthetic concerns
• Most patients are healthy who undergo ear surgery.
 Primary concerns for the anesthetist?
— Patient positioning
— facial nerve preservation
— use of nitrous oxide (N2O)
— homeostasis (bleeding control)
— smooth emergence
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23. Anaesthetic concerns cont…
Position
 Rotation of the head and extension of the neck is necessary
for most ear procedures
—A lateral tilt of the operating table
—Arms should be placed in a neutral position and well
padded.
—15 degree head-up tilt
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24. Anaesthetic concerns cont…
Nitrous oxide and middle ear
How it interfere with surgical field and anaesthetic Mx?
 N2O is more soluble in the blood than nitrogen.
 N2O diffuses in to the middle ear across mucosal blood vessels much
more rapidly than nitrogen can leave.
 This causes overall increase in middle ear pressure.
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25. Anaesthetic concerns cont…
 This increase in pressure is vented by Eustachian tube to escape into the
nasal cavity.
 Middle ear is a closed cavity and nitrous oxide diffuse rapidly causing an
increase in pressure.
 For Tympanoplasty procedure the middle ear remains open until the surgeon
places the graft over the tympanic membrane.
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26. Anaesthetic concerns cont…
 So N2O can be used until 15-20 min before graft placement and then
should be discontinued
 The use of N2O is related to a high incidence of PONV, which is a
direct result of negative middle ear pressure during recovery.
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27. Anaesthetic concerns cont…
Complications resulting from increased pressure
include:-
—Decline in hearing ability
— Displacement of Tympanoplasty graft
—Tympanic membrane rupture
—Difficulty in surgical field
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28. Anaesthetic concerns cont…
Control of Bleeding
 Even a small drop of blood can make the procedure difficult.b/se it is a
microscopic surgery, may cause difficult visullizaton
 To minimize this bleeding-
—Potent opioid pre-induction such as remifentanil
—Avoiding coughing at intubation
—Injecting epinephrine containing solution
—Elevating the patient head can improve venous drainage
—Deliberate hypotension
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29. Surgeon’s view…
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30. Deliberate hypotension
Definition:
—Reduction of the systolic blood pressure to 80-90mmHg
—Reduction of mean arterial pressure (MAP) to 50-65 mmHg or
25 % reduction of baseline MAP
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Anaesthetic concerns cont…

31. Relative contra indication to deliberate hypotension
—Ischemic /cerebrovascular disease
—Coronary artery desease
—Hypovolemia
—Anemia
—Severe hypertension
—Extremes of age
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Anaesthetic concerns cont..

32. Anaesthetic concerns cont…
 How can we achieve?
—Deep inhalational anaesthesia
—High opioid technique/remifentanyl infusion
—IV beta blocker/Vasodilators
—Minimize venous oozing/
 Consider individual patient’s physiology
 Invasive BP monitoring
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33. Anaesthetic concerns cont…
 How?
 Volatile anesthetic agents
—Prevent movement without use of muscle relaxants
—Produce deliberate hypotension and
—Provide adequate level of anesthesia without use of N2O.
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34. cont…
 Anaesthetic Technique: to reduce Venous Ooze?
 Surgical field above heart
 No coughing / straining
—Adequate paralysis
—Smooth extubation
—Spray cords with lidocaine
 Minimize positive intrathoracic pressures
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Anaesthetic concerns cont…

35. Bloodless Field…
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36. Facial nerve preservation
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Anaesthetic concerns cont…

37. Anaesthetic concerns cont…
 Facial nerve exposure is a possibility, and frequently the surgeon will
seek to identify the nerve using a nerve stimulator.
 Nerve stimulator is used, and facial movement is monitored visually
which requires that muscle relaxation be avoided and a volatile drug is
the primary anesthetic.
—At least 30% of the muscle response should be preserved if
muscle relaxant is used.
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38. Anaesthetic concerns cont….
Antiemetic
• Middle ear and inner ear (most common) procedures have a greater
incidence of PONV than general surgical procedures.
• In addition to being unpleasant for the patient, retching and vomiting
increase venous pressure, intracranial pressure, and bleeding, and dislodge
or disrupt delicate surgical grafts and prosthesis.
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39. Anaesthetic concerns cont…
Management PONV?
 If possible, avoid opioids,
 Hydrate patient with intravenous fluids
 Prophylactic combined antiemetics should be administered.
—Serotonin antagonists -ondansetron0.1mg/kg
—Anticholinergics , dexamethasone, and gastrokinetic agents.
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