main surgical intervention in ENT field need anaesthesia

1. Anesthetic consideration
for ENT surgery
Dr. Radhwan Hazem Alkhashab
Consultant anaesthesiologist &
intensivist
2021

2. Introduction
Ear, nose and throat (ENT), maxillofacial and dental surgical
procedures account for a significant proportion of work in most
anaesthetic departments.
03
e
y
A
c
c
o
m
p
l
i
s

3. The Shared Airway
Special problems are caused when the airway is shared by both
anaesthetist and surgeon. If bleeding is anticipated, the airway
must be protected and the oropharynx must be packed to avoid
contamination of the larynx with blood, pus and other debris. If a
pack is used, it should either be labelled or the tail left obviously
emerging from the mouth as a reminder that it must be
removed at the end of the operation.

4. The anaesthetic circuit connections are usually hidden under
the drapes and may well be ‘knocked’ by the surgeon during
the procedure.
At the end of the procedure, the pack, if present, must be
removed and the pharynx cleared of blood and debris before
the trachea is extubated with the patient in a headdown
lateral position. The fact that a pack was used and has been
removed should be recorded.

5. Potential Problems Associated with the Shared
Airway
1) Disconnection of tracheal tube
2) Dislodgement of tracheal tube
3) Access for surgeon or anaesthetist
4) Airway soiling
5) Tube damage, e.g. laser
6) Lack of visual confirmation of ventilation
7) Eye care

6. Tonsillectomy
Almost all are performed under general anaesthesia, with 34% undertaken as day
case surgery.
Premedication is frequently impractical with modern admission practices but
preoperative assessment is mandatory, in particular to obtain any history of
obstructive sleep apnea (OSA) or other airway problems. Often, the patient is young
and otherwise fit.
Surgical access to the pharynx requires the insertion of a Boyle Davis gag. To
facilitate this, a secure airway is usually maintained with a ‘south-facing’ tracheal
tube . Alternatively, a reinforced laryngeal mask airway (LMA) can be used
successfully provided that the surgeon carefully avoids displacement of the LMA
during the insertion and removal of the gag.

7. Vision
Spontaneous ventilation following the use of a short-acting muscle
relaxant can be used to facilitate deep extubation in the lateral head-
down position to protect the airway from soiling during emergence.
Alternatively, positive pressure ventilation can be maintained
throughout the procedure, with extubation fully awake in the sitting
position.
Various surgical techniques can be employed including cold steel
dissection, electrodiathermy, laser and coblation. Blood loss can be
significant & must be maintained regarding fluid replacement; however,
blood transfusion is rarely necessary.
Intraoperative management

8. Postoperative care
Tonsillectomy is painful and requires adequate postoperative analgesia. Which
may includes initial dose of intravenous morphine together with paracetamol
and a non-steroidal anti-inflammatory drug (NSAID).
Multimodal antiemetic therapy should also be used because postoperative
nausea and vomiting is a frequent cause of delay in discharge. There is also
evidence to support the use of steroids for control of emesis and pain, usually
as a single dose of dexamethasone.
The early establishment of oral intake of food, fluids and analgesia encourages
early discharge and should enable most operations to be performed as a day
case.

9. Bleeding Tonsil
The incidence of postoperative hemorrhage increases with age.
Primary bleeds usually occur within 6 hours of surgery and may not be obvious
in the immediate recovery period because the blood is swallowed. The
bleeding is usually a venous or capillary bleed, rather than arterial, and
problems arise because of hypovolemia, aspiration risk, and difficult
laryngoscopy.
Signs suggesting hemorrhage are an unexplained tachycardia ,excessive
swallowing, increased capillary refill time, pallor, restlessness, sweating, and
airway obstruction. Hypotension is a late feature

10. Anesthesia for these patients is challenging, and help from a senior
anesthesiologist should be requested. Patients should be given oxygen; should
be adequately resuscitated; should have hemoglobin, hematocrit, and
coagulation checked; and should have blood typed and cross matched .Large-
bore reliable intravenous access should be established .Laryngoscopy can be
difficult because of the presence of blood clots, continuous oozing of
blood, and reduced venous and lymphatic drainage causing intraoral swelling
and edema

11. Anaesthetic technique for post-tonillectomy
bleeding
After resuscitation, options for anesthesia include a rapid sequence induction,
which is usually the preferred technique, or an inhaled induction. For a rapid-
sequence induction, patients should be in a slightly head-down position,
protecting the airway from aspiration of blood. Some patients may not
tolerate lying supine, and preoxygenation, induction, and cricoid pressure
may have to be applied with the patient semi-upright. The advantage
of a rapid-sequence induction is the rapid induction and control of the airway
with less chance of regurgitation during induction.
The disadvantages are the potential to inhale blood and cardiovascular
depression from induction. A difficult laryngoscopy should be anticipated and
prepared for, and a selection of smaller tracheal tubes may be needed if
airway and tracheal edema is significant. After tracheal intubation, a large-
bore gastric tube should be placed to decompress the stomach and evacuate
swallowed blood at the beginning and at the end of the procedure

12. Adenoidectomy
This is a commonly performed operation in children to improve the
symptoms of otitis media with effusion, and chronic rhinosinusitis. It
is often combined with tonsillectomy and insertion of grommets
Adenoidectomy is also performed occasionally in adults for glue ear
5,000

13. Rigid Endoscopy And Microlaryngoscopy
Rigid endoscopy is performed to facilitate examination, biopsy and treatment of abnormalities of the
upper aerodigestive tract..
General anaesthesia is required, usually with tracheal intubation to provide a safe airway during
surgery. Provided that no difficulty with intubation is predicted,
Intravenous or gaseous induction is followed by the administration of a muscle relaxant dependent
on the anticipated duration of the procedure. In general, a small cuffed tube with internal diameter 4–
6 mm is inserted into the trachea to allow the surgeon greater access to the pharynx. This should be
placed in the left side of the mouth to allow passage of the rigid endoscope down the right.
Examination, with or without biopsy, is usually of a short duration and mivacurium or suxamethonium
is often used. Microlaryngeal tumour resection is often carried out using a precision laser cutting tool
which requires either a tube specifically designed to tolerate lasers or extreme care on the part of the
surgeon to avoid the risk of damage to the tube and potential airway fire

14. A Brief Story
Short-acting opioids provide balanced anaesthesia but morphine may be required for
longer operations. Blood loss is not usually significant and is often controlled by the
topical application of adrenaline with or without local anaesthetic. Safe extubation is
normally achieved with full emergence and recovery of airway reflexes, and careful
pharyngeal suction prior to the removal of the tube.
Occasionally, the surgeon requires access to the larynx without the presence of a
tracheal tube. In this situation, oxygenation can be provided by jet insufflation of the
lungs via a subglottic catheter or an attachment to the endoscope. The catheter
can be inserted into the trachea either down the endoscope or through the
cricothyroid membrane. Anaesthesia is maintained using an intravenous agent,
usually propofol.

15. In addition to modifications to the site at which the jet of gas emerges, changes to the
frequency of jet ventilation have been described. High-frequency (> 60
breaths/min) is used with ventilator rates typically around 100 to 150/min.
Jet ventilation techniques are suitable for most benign glottic pathology and early
malignancy where airway obstruction is not anticipated.
A typical jet ventilation technique includes
Preoxygenation followed by intravenous induction and the administration of
muscle relaxants. Laryngoscopy is undertaken, and topical local anesthetic
(lidocaine) is administered .

16. An LMA is inserted, and ventilation is continued with 100%oxygen until the surgeon
is ready to site the rigid laryngoscope onto which a jetting needle has been
attached. Alternatively, face mask ventilation is continued until the surgeon is
ready to site the laryngoscope.
Anesthesia is maintained with a target-controlled infusion of propofol,
supplemented by bolus administration or infusion of alfentanil or remifentanil is
undertaken.

17. Tracheostomy
Surgical tracheostomy is usually performed in a sedated or anaesthetized intubated
patient. Occasionally, emergency tracheostomy is required in the unintubated
patient, for example in stridor, and may even take place under local anaesthetic if
general anaesthesia with a secure airway cannot be performed
Many procedures now take place percutaneously on the intensive care unit. If
surgical tracheostomy is required, the patient is stabilized and the lungs
ventilated in the operating theatre with the head and neck extended to allow
access. When the surgeon has dissected down to the trachea, the lungs are
ventilated with 100% oxygen and the tracheal tube is withdrawn carefully into the
proximal trachea to allow the tracheal window to be excised without perforating
the cuff.

18. At this point, positive pressure ventilation of the lungs becomes impossible but in
the event of surgical failure to insert the tracheostomy tube, the anaesthetic
tracheal tube can be advanced back down the trachea past the defect to allow
ventilation to be reinstituted. After the tracheostomy tube has been inserted,
the breathing system is connected to it and ventilation confirmed with
visualization, auscultation and capnography. The anaesthetic tube may be
removed and discarded after the tracheostomy tube has been secured

19. Nasal And Sinus Surgery
Various operations are performed on the nose and sinuses to treat and prevent
epistaxis, to improve the nasal airway, to reduce the symptoms of chronic
rhinosinusitis or to improve the external appearance of the nose.
Nearly all can be performed as day-case procedures.
Most nasal procedures are performed under general anaesthesia. The
application of a mixture of topical local anaesthetic agents and other adjuncts
(e.g. Moffat’s solution, which is a mixture of cocaine, adrenaline and
bicarbonate) provides vasoconstriction before surgery.

20. Special care
1. The airway must be secured to allow the delivery of oxygen and a volatile
anaesthetic agent and also to protect the trachea from soiling by blood from the
operative site.
This can be achieved satisfactorily by the use of a reinforced LMA if there are no
specific indications for tracheal intubation such as obesity or the expectation of a
prolonged operation.
2. Special attention must be paid to avoid disconnection or occlusion of the breathing
system by the surgeon, or soiling of the trachea.
3. Balanced anaesthesia is achieved using increments of a short acting opioid or a
longer-acting drug for prolonged or painful procedures.
4. Careful pharyngeal suction is performed at the end of surgery to ensure the removal
of blood and other debris which may have accumulated. The use of a pharyngeal
pack is generally unnecessary but, if used, it is vital to ensure that it has been
removed before emergence. Serious complications, including death, have been
reported after failure to remove a throat pack.

21. Preoperative evaluation
Patients may have a considerable degree of hearing loss, making history taking
and communication difficult. The surgeon should be informed of patients in
whom a hypotensive technique would not be suitable because of excessive
risk.
Children presenting for cochlear implant may have a congenital syndrome as the
cause of their sensorineural hearing loss, such as Stickler or Klippel–Feil
syndrome.11
These conditions are often associated with a difficult airway and require careful
evaluation. Congenital sensorineural deafness can be associated with
prolongation of the QT interval, either in isolation or as part of the Jervell and
Lange–Nielsen syndrome (JLNS), so preoperative ECG screening is
recommended.

22. General anaesthetic techniques
Some procedures can be carried out under local anaesthesia with conscious sedation,
However, the overwhelming majority of cases are performed under general anaesthesia
(GA). Tracheal intubation is often undertaken on account of limited access to the
patient's head, a supraglottic airway device (SAD) can be an acceptable alternative.
SADs have the advantage that neuromuscular blocking agents can be easily
omitted and they also minimise the chances of coughing during emergence, which
can affect the surgical repair. When tracheal intubation is undertaken, careful use of
neuromuscular blocking agents is required, as these drugs reduce the signal
obtained by EMG facial nerve monitors. A single dose of an intermediate-acting
agent (e.g. atracurium 0.5 mg kg) can be given at induction of anaesthesia The
effects will typically subside before facial nerve monitoring is required, which is
usually at least 30–45 min from induction of anaesthesia.

23. Nitrous oxide is typically avoided because of its ability to diffuse into the non-
compliant middle ear cavity faster than nitrogen diffuses out. This is of little
relevance during surgery, as the cavity will be open to air, but once closed a
positive pressure will result.
Total i.v. anaesthesia (TIVA) techniques are frequently used for middle ear surgery
and give an enhanced quality of recovery. When a target-controlled infusion of
remifentanil is used, extubation can be smooth, minimising the effect of
coughing on middle ear pressure.

24. Optimization of the surgical field
Bleeding into the operative field can compromise middle ear surgery by making
identification of anatomical structures difficult and is a risk factor for
cholesteatoma recurrence. There are many methods available for inducing
arterial hypotension;
A low upper body venous pressure can be aided by avoiding the use of tracheal tube
ties, extreme lateral rotation of the head, and excessive administration of i.v. fluids.
A 10° reverse Trendelenburg position is also beneficial for this reason, and has the
added benefit of reducing arterial pressure to the ear by 2 mm Hg for each 2.5 cm
of vertical height above the heart.21
Positive pressure ventilation will raise intrathoracic pressure and thus impede venous
return which will causes reduction in systemic blood pressure.

25. Overall though, positive pressure ventilation is beneficial to surgical conditions, as it
avoids the moderate hypercapnia that occurs in patients breathing spontaneously.
Acute hypercapnia causes an increase in sympathetic nervous activity, which can
raise arterial pressure; it can also cause an acidosis, which leads to vasodilatation in
most vascular beds. Controlled ventilation, aiming for an arterial CO2 concentration
of approximately 4.5–5 kPa, will therefore attenuate both of these effects.
One study showed that operating conditions were superior when a propofol–
remifentanil TIVA technique was used, compared with an isoflurane–nitrous oxide–
fentanyl technique

26. Postoperative nausea and vomiting
Middle ear surgery is associated with a high incidence of postoperative nausea and
vomiting (PONV). Contributory factors include
1. Surgery in younger patients.
2. Longer procedure times compared with other surgeries.
3. Direct stimulation of the vestibular system by drilling adjacent to the inner ear;
and suction–irrigation.
Ondansetron and dexamethasone are both effective prophylactic agents, and efficacy
is increased when they are given in combination.
Other possible minor postoperative complications include a change in taste and
transient facial palsy. Rare complications include cerebrospinal fluid leak,
meningitis, and persistent facial nerve palsy. The majority of patients are
discharged home on the day of surgery, or after a short hospital stay of 12–24 h.

27. Stridor
Stridor is a noisy, high-pitched, predominantly inspiratory sound from turbulent
airflow secondary to upper airway obstruction and can be a medical emergency
requiring immediate intervention. The initial management is the same regardless
of the cause;
100% oxygen should be administered by a facemask with the patient sitting upright
and nebulized ,with epinephrine, 1 mg of a 1: 1000 solution(1 mL) in 5 mL of 0.9 %
saline, repeated every 30 minutes with monitoring. Dexamethasone 0.1 mg/kg
intravenously every 6 hours, helps reduce airway edema ,but takes4 to 6 hours to
work.
Heliox (70% helium, 30% oxygen) greatly increases flow for any given pressure
gradient. In contrast with laminar flow, in which resistance depends on gas
viscosity during turbulent flow, resistance depends on gas density. Heliox leads to
a dramatic decrease in airway resistance and improvement in ventilation.

28. Causes of stridor
Causes of acute stridor include
1. Epiglottitis.
2. Laryngotracheobronchitis.
3. Inhaled foreign bodies.
4. Angioneurotic edema.
5. Tracheitis.
6. Burns.
7. Bilateral vocal cord palsies after surgery.
Chronic causes of stridor include
1. Subglottic stenosis.
2. Laryngomalacia.
3. Malignancy.
4. Mediastinal masses.
5. Webs,cysts.
6. Vascularmalformations.

29. Nasal Vasoconstrictors
Nasal vasoconstrictors are commonly used to reduce bleeding from vascular nasal
mucosa. Some agents ,such as cocaine, have local anesthetic and vasoconstrictor
properties, and others, such as lidocaine, have local anesthetic properties.
Commonly used vasoconstictors include cocaine, epinephrine ,and phenylephrine.
Cocaine has been used alone and in combination with epinephrine. Phenylephrine
has been used in combination with lidocaine, and lidocaine has been used in
combination with epinephrine.
Cocaine has a rapid onset of action. Small doses are vagotonic, producing a
reduction in heart rate, where as increasing blood concentrations cause
tachycardia, hypertension, ventricular tachycardia, and direct cardiac muscle
depression, any of which may cause sudden death, myocardial infarction, and
ventricular fibrillation.

30. Phenylephrine is a potent α-adrenergic agonist and is used as a topical vasoconstrictor
alone or in combination with lidocaine. Guidelines on the topical use of
phenylephrine in the operating room recommend the following:
1. Initial phenylephrine dose should not exceed 0.5 mg, and in children weighing 25
kg or less, it should not exceed 20 micrgmlkg.
2. Blood pressure and pulse should be closely monitored.
3. Severe hypertension should be treated immediately with direct vasodilator.

31. Coroner's Clot
A throat pack is often used around a tracheal tube in an attempt to absorb blood,
limit blood from the nasopharynx entering the oropharynx, and prevent surgical
debris pooling in the laryngopharynx. At the end of surgery, the pack should be
carefully removed and noted. Laryngoscopy and pharyngoscopy should be
undertaken in every patient, and a careful inspection of the oral cavity and
postnasal space should be made. This inspection involves standard laryngoscopy,
followed by neck flexion to encourage any clot to fall past the soft palate ,and
direct visualization of the passage of a suction catheter behind the soft palate.
Any clot left behind can be inhaled after removal of a tracheal tube and lead to total
airway obstruction and death-hence the term coroner's clot.

32. Obstructive Sleep Apnea
In children, enlarged tonsils and adenoids cause varying degrees of pharyngeal
obstruction ranging from simple snoring to upper airway resistance syndrome, in
which partial upper airway obstruction occurs. With very large tonsils and
adenoids, OSA Can be present with loud persistent snoring interrupted by gasping
or choking episodes and silent periods of apnea. Children and adults with OSA are
at increased risk for postoperative respiratory complications .
In severe OSA, hypoxemia, hypercarbia, pulmonary hypertension, and Cor-pulmonale
can be present. These children should be looked after in specialist pediatric
centers with appropriate postoperative monitoring and high dependency care.

33. Postextubation laryngospasm and stridor
The incidence of laryngospasm and stridor after removal of a tracheal tube is greater
than that after recovery with a Flexible LMA .The incidence of laryngospasm after
routine tracheal tube extubation following tonsillectomy is reported as l2% to 25%
Attempts to reduce the laryngospasm involve either:
1. Topical anesthesia to the upper airway" limiting the exaggerated glottic closure
reflex and subsequent laryngospasm. (Topical lidocaine (4mglkg) can be used in
concentrations of 2% to 4% and is as effective as intravenous lidocaine (I mg/kg).
2. Intravenous agents administered close to extubation.(Intravenous magnesium,
subhypnotic doses of propofol," and lidocaine).
3. Increasing the depth of anesthesia and limiting glottic closure reflex-mediated
laryngospasm.

34. Foreign body aspiration
Foreign body aspiration is the most common indication for bronchoscopy in
children I to 4 years old. Inhaled foreign bodies can lodge in the larynx, trachea
,main bronchi, or smaller airways ,and their effects depend on the duration,
degree ,and site .Peanuts are commonly inhaled foreign bodies, and as they
absorb water, they swell, become friable, cause a chemical irritation of the
airway, and require urgent removal. Patients with foreign bodies within
the larynx and trachea present with acute dyspnea ,stridor, coughing, and cyanosis.
The Heimlich maneuver may be needed to Dislodge the obstruction. If the
obstruction is in the bronchus ,the child is more likely to be wheezy ,coughing,
and dyspneic with evidence of decreased air entry on the side of the
obstruction.
Chest radiographs may not reveal the lesion because most foreign bodies are
radiolucent, so a positive history and clinical symptoms of aspiration may be
the only guide to the diagnosis. A child may present much later if the
obstruction does not pose a functional problem with mucosal irritation, edema
,and pneumonitis distal to the obstruction.

35. Management of F.B. aspiration
Dislodging an inhaled foreign body can convert a partial obstruction to a more
severe or even complete obstruction. The general principle of removal of
inhaled foreign bodies during laryngoscopy and tracheobronchoscopy is to
maintain spontaneous ventilation and reduce the chances of the foreign body
being pushed distally into the airway .In practice ,however ,maintenance
of spontaneous ventilation in a critically obstructed airway can be extremely
difficult to sustain, and intermittent positive pressure ventilation may be
needed. Some centers routinely use controlled ventilation with muscle
paralysis

36. F.B. aspiration Cont.
Sedative premedication should be avoided because it may precipitate total
airway occlusion. Induction is usually by an inhaled technique with
sevoflurane or halothane in oxygen.
At a deep plane of anesthesia, laryngoscopy is performed, and topical local
anesthetic (lidocaine) is administered. Intravenous anticholinergic agents
(atropine, 20 miclkg, or glycopyrrolate, 10 mic/kg) can help reduce secretions
and reflex bradycardia associated with airway instrumentation.

37. F.B. aspiration Cont.
Some bronchoscopes allow the attachment of a T-piece to a side arm on the
bronchoscope through which oxygen and volatile agent can pass directly
into the distal trachea. Here the bronchoscope acts in a similar manner to
an uncuffed tracheal tube.
Some bronchoscopes do not allow T-piece attachment, however, and
insufflation techniques are required.
Postoperative care requires observation for airway edema and intravenous
steroids (dexamethason 0.1 mg/kg), antibiotics, and humidified oxygen;
high-dependency postoperative care may be needed

38. Epiglottitis
Acute epiglottitis is an acute inflammatory disease of the epiglottis, arytenoids, and
aryepiglottic folds. The onset and progression of the symptoms can be rapid
and lead to complete airway obstruction, hypoxemia, and death. In adults, the
incidence has been around I per 100,000adults Per year
Adults and children present with a sore throat, fever ,dysphagia ,drooling, open
mouth, muffled voice, stridor, and respiratory distress

39. Management of acute epiglottitis
For adults and children, preparation for a difficult intubation and emergency
tracheostomy should be made. Inhaled induction with sevoflurane or
halothane in oxygen is begun with the child usually sitting or in the
preferred position. Nitrous oxide is not used. After inhaled induction,
further monitoring and intravenous access are established as anesthesia
deepens. Intravenous fluids and atropine may be administered to reduce
the likelihood of bradycardia associated with intubation. On laryngoscopy,
the epiglottis and aryepiglottic folds are swollen, and the classic
‘cherry-red“ epiglottis may be seen.
An uncuffed tracheal tube usually I to 3 mm smaller than normal is placed ,
initially this is an orotracheal tube & when the child become stable the tube
changed to nasal one for 24-72 h in pediatric ICU .