Airway Anaesthesia for Final FRCA Written Final FRCA Teaching

July 2016

Common questions

Airway emergencies:

• Bleeding tonsil

• Inhaled foreign body

• Croup/epiglottitis

Topical airway stuff:

• Tracheostomy/DAS guidelines

• NAP 4

• BJA Education

ENT:

• Laser airway surgery

• Jet ventilation

• Airway imaging

Maxfacs:

• Intraoral abscesses

• Facial fractures

Equipment:

• Supraglottic airways

• Fibreoptic scope

Quick quiz

Anatomy, nerve supply and anaesthesia

Discuss intubation options

17 year old female with fractured mandible requiring ORIF. MO 1cm. Very anxious. Requesting EMLA for cannulation.

27 year old male with facial swelling due to intra-oral abscess requiring I &D in theatre. MO 1cm.

54 year old male for microlaryngoscopy for biopsy of laryngeal lesion. Normal MO. Previous surgery abandoned due to failed direct laryngoscopy. PMH radiotherapy for tonsillar cancer.

Facial fractures

Intra-oral abscesses

Maxillary infection

Wisdom teeth

Airway Management Considerations

Superficial

Reduced nasal patency

Trismus related to pain unless spread

to other spaces

Floor of mouth

Trismus

Raised floor of mouth (can’t protrude

tongue)

Reduced oro-pharyngeal space

Potential rupture on airway

manipulation

Dysphagia, drooling

Supraglottitis-oedema of laryngeal

structures

Difficult tracheal access

Masticator

Severe trismus

Rupture on manipulation

Pharyngeal

Neck stiffness

Reduced oro-pharyngeal space

Rupture

Dysphagia, drooling

Airway distortion/oedema and

stridor

Distant spread (mediastinitis)

Implications of radiotherapy

Site of cancer Pathology Problems Implications

Face & Buccal mucosa Necrosis

Mucositis

Oral thrush

Orofacial pain

Ulceration

Fistula formation

Difficult mask ventilation

Mucosal bleeding

TMJ Fibrosis Trismus Difficult laryngoscopy

Tongue Fibrosis

Inflammation

Glossitis

Glossomegaly

Reduced tongue mobility

Difficult laryngoscopy

Dentition Increased risk caries Loose teeth

Dental loss

Difficulty mask ventilation

Risk of dental trauma

Floor of mouth Fibrosis Reduced mobility Difficult laryngoscopy

Mandible Osteonecrosis Micrognathia

Mandibular recession

Difficult mask ventilation

Difficult laryngoscopy-

reduction in mandibular

space

Suprahyoid region Fibrosis

Oedema

Firm/woody neck tissue

Skin tethering

Difficult laryngoscopy-

limited atlanto-axial

flexion/extension

Lower airway Epiglottic & glottic

oedema

Snoring

Hoarseness

Cough

Difficult laryngoscopy

Difficult endotracheal

intubation

SAQ One

A 71-year-old patient requires a rigid bronchoscopy for biopsy

and possible resection of an endobronchial tumour.

a) What are the possible indications for rigid bronchoscopy

under GA?

b) What are the options for anaesthesia and ventilation during

bronchoscopy?

c) What are the possible complications of rigid bronchoscopy?

d) What are the indications for bronchoscopy on the intensive

care unit?

Diagnostic Therapeutic

Massive haemoptysis

Massive haemoptysis

Biopsy tumour Stent insertion

Tracheal dilation

Removal inhaled FB

Tumour debulking

Indications for rigid bronchoscopy

Options for anaesthesia/ventilation?

• Apnoeic oxygenation

• Spontaneous assisted ventilation

• Controlled ventilation

• Manual jet ventilation

• High frequency jet ventilation

Jet ventilation

• Low frequency vs high frequency

• Jet stream from high pressure source

generates tidal volume

• Passive expiration from lung and chest

wall recoil (NB HFOV)

Manual jet ventilation

Indications

Physiological principle?

Gas exchange by bulk flow

How to use?

High frequency jet ventilation

Small Vt (1-3 ml/kg) from a high pressure jet at supra-physiological frequencies 1-10Hz

• Gas exchange: pendelluft/

laminar flow/longitudinal dispersion

• Facilitate surgical access

• Lower mean airway pressure

(useful if gas leak)

Complications

Bronchoscopy related Anaesthesia related

Airway bleeding Hypoxaemia

Trauma to vocal cords Hypercarbia

Laryngospasm Barotrauma/Pneumothorax

Aspiration Surgical emphysema

Bronchospasm Awareness?

Oedema-post op stridor Gastric distension

Bronchoscopy in ICU

Inspection Sampling Therapy

Aspiration x x x

Infection x x x

Lobar

collapse/atelect

asis

x x x

Airway

management

x x

Airway

assessment

x x

Foreign Body x x

Strictures/steno

sis

x x

Haemoptysis/h

aemorrhage

x x

SAQ Two

A 54 year old patient with base of tongue cancer presents for a hemiglossectomy and radial forearm free flap reconstruction a) What conditions/procedures require the formation of a free flap? (2 marks) b) Which specific factors must the anaesthetist consider when assessing this patient prior to surgery (10 marks) c) List the benefits of a free flap reconstruction (2 marks) d) What are the causes of flap failure and how may they be prevented in the perioperative period? (6 marks)

Free Flap Surgery

Conditions requiring free flap

Reconstructive surgery head and

neck cancers

Breast reconstructive surgery

Reconstructive hand surgery

Burns

Trauma

Donor Sites in H&N

Intra-oral defects

• Radial forearm

• Anterolateral thigh

Mandibular reconstruction

• Fibula

• Iliac crest (DCIA)

• Scapula

Pre-operative assessment

Patient:

Smoking

Alcohol

Pre-op BP

Nutrition

Anaesthetic:

Airway-previous radiotherapy, site of lesion

Side of flap (venous/arterial access)

Surgical:

Duration

Positioning

Temperature

DVT prophylaxis

Tracheostomy formation

Benefits of free flap

① Integrity

② Function

③ Aesthetics

• Benefits of taking tissue from a distant site

• Better outcomes if future radiotherapy

needed

• Minimal donor site morbidity

Causes of flap failure

• Primary ischaemia

• Reperfusion injury

• Secondary ischaemia

Free flap physiology

• Intact arterial and venous system

• Denervated

• No lymphatic drainage

Physiological principles?

• Hagen-Pouiselle

• Laplace

Flap Failure

Arterial occlusion

Flat

Pale

Cool

Decreased or absent CRT

No bleeding on pinprick

Loss of arterial Doppler signal

Venous occlusion

• Oedematous

• Congested (pink-

purple)

• CRT brisk

• Dark bleeding on

pinprick

• Loss of venous

Doppler signal

SBA You are called to see a patient with tracheostomy . His saturation dropped from 98% to 86% on 50% oxygen. What will be your next immediate step?

a. Call for help

b. Connect the tracheostomy tube to a circuit and do manual bagging

c. Give 100% oxygen

d. Pass suction catheter through tracheostomy tube

e. Remove tracheostomy tube

SBA

70 year old male undergoes radical neck dissection for

malignancy. Patient becomes unstable when tumour is

being dissected from carotid sheath. SBP drops to 60,

HR 110, SpO2 87% and ETCO2 1.9kpa. The most likely

is:

a. Anaphylaxis

b. Carotid sinus manipulation

c. Myocardial ischaemia

d. Tension pneumothorax

e. Venous air embolism

SBA

Following a difficult intubation but easy bag and mask

ventilation in an obese lady you cannot hand

ventilate. What will you do first?

a. Take out ETT

b. Look at capnograph trace

c. Look at oxygen saturation

d. Give nebuliser

e. Give muscle relaxant

SBA

You are called to see a patient in recovery one hour following a thyroidectomy operation. He has difficulty breathing and his O2 saturation has dropped to 89% from 97% despite a FiO2 of 60%. The front of his neck appears swollen despite no blood in the suction drain.

What will be your next line of action:

a. Get the surgeons to re-explore the wound

b. Open the clips in the front of the neck

c. Give CPAP using NIV

d. Nebulised Adrenaline

e. Urgent USS

MCQ

Complication of percutaneous tracheostomy

are:

a. Tracheal stenosis

b. Surgical emphysema

c. Endobronchial intubation

d. Hypothyroidism

e. Trachea-oesophageal fistula

MCQ

With regards to high frequency ventilation:

a. I:E ratio 1:3 is used

b. It is used in management of broncho-pleural fistula

c. Increases FRC

d. Requires continuous infusion of muscle relaxants

e. Reduces the risk of barotrauma

What we’ve covered:

Anatomy and nerve supply of the upper airways

Relevance of intra-oral abscesses & facial #

Implications of head and neck radiotherapy

Bronchoscopy/principles of jet ventilation

Free flap surgery

References

Pathak et al. Ventilation and anaesthetic approaches for rigid bronchoscopy. Annals American Thoracic Society. 2014, 4: 628-634.

Conclon, C. High frequency jet ventilation. Anaesthesia Tutorial of the Week 271. 2012.

Evans et al. Jet Ventilation. CEACCP. 2007, 7: 2-5.

Darshane et al. Responsive contingency planning: a novel system for anticipated difficulty in airway management. BJA 2007, 99(6): 898-905.

Adams J and Charlton P. Anaesthesia for microvascular free tissue transfer. BJA CEPD 2003,3:33-37.

Nimalan N. Anaesthesia for free flap breast reconstruction. BJA Education. 2015.

Kabadayi. S Bronchoscpy in critical care. BJA Education 2016.