Ent

Front 1

Anatomy of Larynx

Back 1

1. Bone
a. Hyoid bone C3
2. Cartilage (3 unpaired and 3 paired)
a. Unpaired
i. Epiglottis
ii. Thyroid cartilage
iii. Cricoid cartilage
b. Paired
i. Arytenoid cartilages
ii. Corniculate cartilages
iii. Cuneiform cartilages
3. Ligaments (4 extrinsic and minor intrinsic)
a. Thyrohyoid membrane
b. Hyo-epiglottic ligament
c. Cricothyroid ligament
d. Cricotracheal ligament
4. Muscles (3 extrinsic and 6 intrinsic)
a. Extrinsic
i. Sternothyroid
ii. Thyrohyoid
iii. Inferior constrictor
b. Intrinsic
i. Posterior cricoarytenoid
ii. Lateral cricoarytenoid
iii. Interarytenoid
iv. Thyroarytenoid
v. Vocalis
vi. Cricothyroid
5. Vascular supply
a. Arterial
i. Superior laryngeal (from superior thyroid artery)
ii. Inferior laryngeal (from inferior thyroid artery)
b. Venous
i. Into corresponding superior and inferior thyroid veins
6. Nerve Supply
a. Branches of vagus (X) nerve
i. Superior laryngeal nerve
I. External branch: motor to Cricothyroid
II. Internal branch: sensory above vocal cords and inferior surface of epiglottis (surface of epiglottis supplied from glossopharyngeal)
ii. Recurrent (inferior) laryngeal nerve
I. Motor to all intrinsic muscles of larynx (except Cricothyroid)
II. Sensation below vocal cords

Front 2

Laryngectomy and Radical Neck Dissection Issues

Back 2

Anaesthetic Factor
1. Airway
a. Mass effect of tumour
b. Shared airway (remote anaesthesia)
2. Circulation
a. IV access
b. Maintain blood pressure with 20% of normal
c. Blood loss
d. Fluid management
3. Pressure areas
4. Length of procedure
5. Fatigue
6. Pain usually not a problem
Patient
1. Co-existing disease
2. Nutrition
Surgical
1. Position: head up to reduce bleeding
2. Casual vandalism
a. Airway
b. Eyes
c. Lips
d. teeth
3. Damage to adjacent structure
a. Blood vessels
b. Nerves:
i. recurrent laryngeal, phrenic, vagus
ii. Carotid stimulation
c. Muscles
d. Thyroid/parathyroid
e. Pneumothorax
f. Air embolus

Front 3

Remote Anaesthesia Issues

Back 3

1. Airway
2. Access
3. Casual vandalism
a. Airway
b. Eyes
c. Lip
d. Teeth
e. Brachial plexus

Front 4

Tonsillectomy Issues

Back 4

Background
Common surgical procedure in children with bimodal peaks age 4 and 16-17.
Respiratory complications are common in less than 3 years
Secondary haemorrhage is common

Issues
Indication for procedure: airway obstruction or recurrent infection
Obstruction
Apnoea
URTI: risk of respiratory complication and bleeding
Bleeding
Post operative analgesia
Paediatrics: separation anxiety, cooperation and parent anxiety

Front 5

Rebleeding Tonsillectomy Issues and management

Back 5

Issues
1. Full stomach
2. Hypovolaemia
3. Airway
4. Location and time
a. Peripheral hospital
b. Middle of the night

Management
History:
General health: infection
Surgical: when was tonsillectomy done, known complication, timing and quantifying amount of bleeding.
Respiratory: breathing, stridor and ability to lie flat
CVS: hydration status, amount of resuscitation to date
Prev anaesthetic: ease of intubation, IV access, allergy
Examination
Airway assessment
Respiratory effort
Fluid status: BP, HR, Urine output and capillary refill
Investigation
Hb, PLT, COAG, G&S

Preparation
Resuscitation: 2 large bore cannula, IV fluid titrates to HR, BP and urinary output.
Assistant and surgeon in OT
Drug prepared for RSI
Monitoring: routine
Equipment: difficult airway trolley, two bright laryngoscope, assorted size of ETT, with a smaller size available, bougie, video laryngoscope, two suction devices, NGT

Induction
Two methods described
1. RSI: allow rapid airway protection but laryngoscope may be difficult. It is my referred method.
2. Inhalational induction on left lateral position: takes longer, with a non-fasted patient and unfamiliar technique.

Front 6

Nasal surgery intraoperative HTN Differential Diagnosis

Back 6

Differential Diagnosis
Physiological
1. Nociception
2. Inadequate anaesthesia
3. Hypoxia
4. Hypercapnia
Pathological
1. ICP: check Cushing response
2. Pre-eclampsia
3. Endocrine
a. Thyroid storm
b. Conn syndrome/Cushings
c. Phaeochromocytoma
Iatrogenic
1. Anaesthetic: vasopressor, inotropes, MH
2. Surgical: adrenaline in LA, cocaine
3. Measurement error

Front 7

HTN intraoperative management

Back 7

Management of HTN
Aim: prevent myocardial ischaemia and hypertensive stroke
1. ABC
2. FiO2
3. Deepen anaesthesia and given analgesia
4. Pharmacological
a. HR: high β-blockers: metoprolol 1-2 mg, labetalol 5-10mg, Esmolol 0.5 mg/kg
b. HR: low vasodilator: hydralazine, GTN, SNP
i. β-blocker may cause unopposed -vasoconstriction
ii. Generally vasodilator first
5. Recovery
a. ECG and troponin if suspect myocardial injury
6. Subsequent
a. General physician referal
b. Secondary HTN
i. 24 hour urinary catecholamine
ii. TFT

Front 8

Throat Pack: prevention

Back 8

1. Inform surgeon and nursing staff
2. Tie to tube
3. Mark on the forehead
4. Include in the count
5. Inform changeover staff

Front 9

Mastoidectomy Issues

Back 9

Surgical:
1. Monitoring of facial nerve and nerve stimulation: normal neuromuscular function at the time of surgery.
Anaesthetic:
1. Remote anaesthesia
2. Pressure area
3. Nitrous oxide should not be used
4. Analgesia usually not an issue
5. Preference Propofol TIVA and remifentanil
Patient:
1. PONV: Apefel
a. Female
b. Previous PONV
c. Non-smoker
d. Opioid use (not so much for Mastoidectomy)

Front 10

Myringotomy and Grommets Issues

Back 10

Common procedure in children aged 6 months to 3 years that is performed as a day case.
Indications
Recurrent otitis media
Persistent middle ear fluid, glue ear
Hearing loss
Speech delay
Issues
1. Shared airway
2. Obstruction
3. Laryngospasm

Patient
1. Craniofacial syndromes
2. Sleep apnoea: may have respiratory insufficiency and require overnight hospitalisation
3. Recent URTI
Anaesthetic
1. Shared airway

Front 11

Risk with URTI

Back 11

1. Increased laryngospasm
a. Hyper-reactivity and respiratory muscle weakness for 2 weeks (JAMA 1974)
b. 3 x increase in bronchospasm and laryngospasm with recent URTI (Tait and Knight Can J Anaes 1987)
c. ETT in child with URTI increase risk of adverse event by 11x (Cohen A&A 1991)
d. More common in less than 1 year old (Anaesthesiology 1991)
2. Coughing
3. Breath holding
4. Obstructed airway 2-7 x
5. Increased risk of hypoxia
a. Recent URTI and GA with face mask no increase rate of complications in the URTI group compared with control (Tait Anaesthesiology 1987) but increased desaturations (Anaesthesia 1992)

Front 12

When to cancel with URTI

Back 12

1. < 1 year old
2. Lethargic and look unwell
3. Temp > 38
4. Production cough
5. Green/yellow nasal discharge
6. Chest infection
7. Need for intubation

Front 13

When to reschedule URTI

Back 13

Wait 4-6 weeks

Front 14

Epiglottitis Assessment

Back 14

Inflammation of the epiglottis commonly caused by haemophilus influenza.
It is now rare to see as people are vaccinated against H. influenza
History
Clinical triad: drooling, dysphagia and distress classic presentation.
High fever 40C.
Abrupt onset of stridor and laboured breathing
Dysphagia
Sore throat and anxiety

Examination
Toxic, shock, anxiety
Chin hyperextended and body leaning forward. (tripod sniffing position)
Stridor, marked suprasternal, subcostal and intercostal retractions

Front 15

Epiglottitis Management

Back 15

This is an emergency:
Securing the airway is of upmost priority.
Transfer patient to OTAsse
Management of patient
1. DO NOT examine or insert iv
2. Immediate transfer to theatre
3. Call for help
a. Senior anaesthetist
b. ENT surgeon
4. Keep sitting up
5. Inhalational induction with 100% O2
6. Once obtunded
a. Monitoring on
b. Iv access
c. Atropine
d. Bloods
e. CPAP
7. Make sure patient is in a deep plane of anaesthesia
8. Intubate patient with ETT 1-2 size smaller
9. If unable to see larynx press on the chest to see air bubbles
10. Change to nasal tube if it was an easy intubation
11. Transfer to ICU and Ceftriaxone
12. Extubate once temp settles and leak around the tube

Front 16

Tracheostomy Issues

Back 16

This is generally an elective procedure
Airway fires
Bleeding
Hazardous times
1. Changing the trachy
2. Insertion of trachy
3. During transport and on return to ward

Front 17

Tracheostomy Assessment

Back 17

Elective or emergency
Airway:
1. Short fat necks
2. grade of intubation
3. Type of tube at present
Breathing
1. Ventilator dependence
2. Setting: VT, airway pressure, frequency
3. Oxygenation
Circulation
1. Inotrope dependence as low as possible
COAG
1. Correction to avoid airway bleeding
2. Normal INR, platelets
Timing
1. Out of hours

Front 18

Tracheostomy anaesthetic

Back 18

1. General anaesthesia with relaxant: provide optimal surgical condition
2. Severe airway compromise: LA
3. Position:
a. Supine with head extension
b. Semi-upright for severe airway obstructions
4. For difficult intubation grade 3-4: bougie prior to pulling out tube

Front 19

Jet Ventilation Complications

Back 19

1. Barotrauma
a. Pneumothorax
b. Pneumomediastinum
c. Pneumopercardium
d. Subcutaneous emphysema
e. Necrotizing tracheobronchitis
2. Malposition
a. Gastric distension and rupture
b. Necrotizing enterocolitis in neonates
c. Dysrhythmia
3. Inadequate gas exchange
a. Hypoxaemia
b. hypercapnia

Front 20

Microlaryngoscopy Issues

Back 20

1. Short stimulating procedure
2. Shared airway
3. Whether laser is going to be used or not
4. Awake patient at the end of the procedure

Front 21

Unfamiliar Environment Issues

Back 21

1. Assistant: unfamiliar and expectation
2. Drugs: preparation and location
3. Monitoring: different monitors and availability
4. Equipment: location, suction, advanced airway equipment may be lacking, ventilator

Front 22

Airway tumour Assessment

Back 22

Routine airway assessment
Mass: friable, bleeding, size, location (retrosternal involvement), invasion to nearby structure,
Metabolic: electrolytes, hormonal effects
Metastasis:
Medication: chemotherapy or radiotherapy
Remember often airway tumour:
1. heavy smokers, alcoholics
2. Cardiac, respiratory and hepatic issues

Front 23

Airway Trauma Issues

Back 23

Patient
1. Patient full stomach
2. Psychology/EtOH/Drugs/cooperation from patient
Anaesthesia
1. Unfamiliar environment (ED)
2. Difficult airway
3. Airway trauma: airway manipulation needs to be under direct vision (fibreoptic)
Surgical
1. Unclear of actual procedure
2. ENT surgeon needs to be scrubbed and available
Management Principle
1. Spontaneous breathing patient
2. Visualise airway as further airway injury possible

Front 24

Inhaled Foreign Body Assessment

Back 24

Epidemiology
FB aspiration is one of the leading causes of death in young children.
300 deaths per year in US
Commonly in 1-3 years old
Most die at the time of aspiration due to complete airway obstruction.
Most common object is food with nuts most common. (Peanuts account of 1/3 of all FB aspiration)

History
1. Early vs late presentation
a. Time of presentation since event
b. Early can go from well pink child to severe acute upper airway obstruction.
c. Late: signs of lower respiratory tract infection.
2. Size, shape and type of object inhaled:
a. suggest site of lodgement
b. likelihood of visibility on CXR
c. Urgency: battery corrosive
3. Site of object within airway (trachea, main bronchus, distal airways)

Sudden choking followed by coughing and wheezing

Examination
Early
1. Respiratory distress: cyanosis, stridor, severe intercostal/sternal recession
2. Change of voice/barking cough: laryngeal oedema/upper airway obstruction
3. Consciousness: reduced → of upper airway obstruction
Late
1. Pneumonia: fever, cough, tachycardia, tachypnoea and focal chest signs

Investigation
CXR: include neck: sensitivity 67-82% specificity 44-74%
Normal CXR especially within 24 hours does not exclude diagnosis of FB
1. Normal
2. Gas trapping
3. Mediastinal shift
4. Atelectasis
5. Lobar collapse/consolidation

Front 25

Foreign objection in airway management

Back 25

Immediate
1. Does the child have effective cough?
a. If yes encourage cough
b. Physiotherapy/intervention (back blows or chest/abdominal thrust)
i. Less effective
ii. Risk of dislodging the FB and worsens the obstruction
2. Is the child conscious?
a. No cough but conscious
i. 5 back blows followed by 5 chest thrusts
b. Unconscious
i. BSL
Anaesthesia Technique
Preparation
1. Adequate Staff
a. Senior anaesthetist (paediatric anaesthetist)
b. ENT surgeon with ridged bronchoscope ready
2. Fasting
a. Don’t worry about it too much especially in compromised situations
b. Premedication
i. Generally no premed: maintain perioperative respiratory drive
ii. Atropine/glycopyrrolate:
I. reduce bradycardia via vagal stimulation
II. reduced airway secretions
3. Antibiotics: especially in late and pneumonia
4. Intravenous access: may insert after induction
Induction
5. Inhalational induction
a. Sevo + 100% oxygen
b. No nitrous due to gas trapping
6. Lignocaine 4%
a. Reduce cardiovascular and tussive response to bronchoscopy
Maintenance
1. Spontaneous ventilation
a. Catheter to the sidearm of a Storz bronchoscope
i. Allow volatile, oxygenation and ventilation
b. Possible to run low dose TIVA to maintain deep anaesthesia
2. Paralyse and positive pressure ventilation
a. Decrease amount of coughing
b. However, jet ventilation may push foreign object further down.
Postoperative
7. Depend on child
8. CXR to exclude pneumonthorax
9. Antibiotics if there is delayed treatment such as pneumonia

Front 26

Thyroid Surgery issues

Back 26

Preoperatively
1. Thyroid activity
2. Potential airway problem
Intraoperatively
1. Remote anaesthesia from airway
2. Thyroid storm
3. Coughing
4. Surgeon
a. Vascular:
i. Bleeding
ii. Air embolism
b. Nerves: vagus, recurrent laryngeal, phrenic, carotid reflexes
i. View cords at the end of surgery
ii. Special ETT: required neuromuscular function: no relaxant and no coughing
c. Parathyroid
d. pneumothorax
Postoperative
1. Airway (stridor)
2. Pneumothorax
3. Post-operative bleeding
4. Thyroid storm/Myxoedema coma
5. Hypocalcaemia

Front 27

Post-thyroidectomy Stridor Differential Diagnosis

Back 27

Anaesthetic
1. Foreign object
2. Laryngospasm
3. Residual NMB
4. Decreased LOC
Surgical
1. Bleeding
2. Nerves (recurrent laryngeal nerve injury)
3. Tracheomalacia
4. Parathyroid (hypocalcaemia)

Front 28

Dental Abscess issues

Back 28

Patient:
1. Trismus
2. Airway contamination
Anaesthetic
1. Shared airway
2. Difficult airway
Surgeon
1. ?local anaesthetic

Front 29

Advantage of laser surgery

Back 29

1. Good haemostasis
2. Minimal perioperative oedema
3. Preservation of normal tissue
4. Surgical precision
5. Rapid healing
6. Minimal scar formation

Front 30

Laser Safety

Back 30

Patient:
1. Safety glasses and eye protection
2. Water based lubricants and flame resistant draps
Surgical:
1. Non-alcoholic prep
2. Instruments: matte finish
3. Laser: minimal power, smallest spot size and shortest exposure time
4. Bucket of water
Anaesthetic:
1. Lowest FiO2 and no nitrous
2. Special ETT/no ETT
3. Double cuff: inflate with dye
4. Staff:
a. Training
b. glasses
c. Warning sign outside
d. laser safety officer

Front 31

Airway Management for Laser

Back 31

1. Protected conventional tube (aluminium foil)
2. Non-combustible tube
a. Benjet tube
b. Mallincrodt laser flex
c. Xomed laser shield II
3. No tube
a. Venturi jet ventilation
b. High frequency jet ventilation

Front 32

Airway Fire management

Back 32

1. Remove source of fire (the laser!).
2. Stop ventilating, disconnect circuit, extubate.
3. Extinguish fire in bucket of water (MUST have one ready!).
4. Mask ventilate with 100% O2,
5. Continue anaesthesia i.v.
6. Direct laryngoscopy & rigid bronchoscopy for damage and debris.
7. Reintubate if damage.
8. Blowtorch fire may need distal fibreoptic bronchoscopy and lavage.
9. Severe damage may need low tracheostomy.
10. Assess oropharynx and face.
11. CXR.
12. ?Steroids.
13. ICU

Front 33

Special ETT's.

Back 33

Some special tubes have been made to deal with the problems of flammability and cuff rupture. From the literature it doesn't appear that these are much better than a taped tube but I'll describe them anyway.

Bivona Fome-Cuff.
This is an aluminium spiral tube with a silicone polyurethane foam cuff in a silicone envelope. The foam is self inflating (it has to be sucked down) thus preventing deflation in the event of cuff rupture. It should nonetheless be filled with coloured saline to identify rupture. Its problem is the trauma an undeflated cuff will cause in the event of perforation. It also has a high incidence of sore throat and is only recommended for use with a CO2 pulsed laser.

Xomed Laser-Shield.
A silicone elastomer tube containing metallic powder only for use with pulsed CO2 laser less than 25W. There is still a risk of perforation and fragmentation into silica ash and wet pledgets should be placed around the cuff.

Mallinckrodt Laser-Flex.
An airtight stainless steel spiral wound tube with two PVC cuffs which should be filled with coloured saline. The distal cuff maintains the seal if the proximal one is ruptured. It is only recommended for CO2 and KTP-Nd-YAG, not the ordinary YAG.