Airway Management Flashcards
What are the airway concerns specific to a patient undergoing bimaxillary osteotomy?
This is a shared airway case
- Nasal intubation, with risk of epistaxis and trauma
- Risk of damage to tube
- Lack of access to patient’s head intraoperatively
- May have comorbidities that make airway difficult
The patient may require jaw wiring or inter maxillary fixation
- Difficult reintubation
- Risk of retained throat pack
- Risk of undetected postoperative bleeding
Other than nasal intubation, how might you manage the airway for a maxillo-facial operation?
Retromolar intubation
Submental intubation
Tracheostomy
What measures can be taken to reduce the risk of intraoperative bleeding?
Head up position
Avoid hypertension
Local anaesthesia with adrenaline
Tranexamic acid
What are the benefits of TIVA for maxillofacial surgery?
Reduced post operative nausea and vomiting
Reduced coughing on emergence
Easier to manage intraoperative hypertension
What measures should be taken to avoid a retained throat pack?
Label the patient’s forehead
Label the tube
Leave part of the pack visible
Checklist in patient’s care plan or notes
Include pack in swab count
Which lasing medium is used for laryngeal tumour surgery and why?
CO2 gas
Far infrared 10 600nm
Cutting and coagulation
Argon is used for dermatology
Ho:YAG is used for lithotripsy
Ruby for tattoo removal
Nd:YAG for GI bleeding
According to NAP-4, where did 20% of all airway incidence occur?
Intensive care unit
What history and examination features are particularly of relevance to airway management in a patient undergoing thyroidectomy?
Duration of goitre - a large, chronic goitre is a risk factor for post-operative tracheomalacia
Ability to lie flat, stridor or shortness of breath, and whether this is positional
Vocal changes
Ability to palpate below thyroid, evidence of retrosternal extension
Tracheal deviation
Evidence of superior vena cava obstruction - Pemberton’s sign
What investigations should be performed prior to a patient undergoing thyroidectomy?
Thyroid function - risk of intraoperative thyroid storm
Echocardiogram and ECG
Chest xray
CT neck and thorax to assess trachea and retrosternal extension
Full blood count as risk of intraoperative bleeding
Spirometry - may demonstrate fixed upper airway obstruction
What would severe stridor immediately after extubation suggest?
Bilateral recurrent laryngeal nerve palsy
What is the immediate management of an expanding neck haematoma?
- 100% oxygen
- Remove clips/sutures
- Sit patient upright
- Return to theatre
- Prepare for difficult airway with ENT surgeon on standby for emergency awake tracheostomy
How can you perform a Valsalva manoevure during an operation, and what is its purpose?
- Switch from ventilator to manual ventilation
- Close APL valve to at least 40cmH2O
- Squeeze bag until pressure 30cmH2O
- Hold for at least ten seconds
- Purpose is to raise intrathoracic pressure and therefore jugular venous pressure
- This will exaggerate any venous bleeding allowing the surgeon to detect and treat it
What factors increase risk of sore throat post operatively?
Large ET tube
High cuff pressure
Difficult intubation
Longer anaesthetic
Nasogastric tube
Non-humidified breathing system
How can the risk of dental injury be reduced?
Preoperative dental exam
LMA
Regional anaesthesia
Blind nasal intubation
Bite block
Deep extubation
Senior operator
What are the commonest nerve injuries due to positioning during anaesthesia?
Brachial plexus injury
Ulnar nerve injury
Common fibular nerve injury
What are the features of common peroneal nerve palsy?
Foot drop
Weak dorsiflexion and eversion
Weak extensor hallucis longus
Paraesthesia over dorsolateral foot and ankle
What is the definition of a difficult airway?
There are many ways to define the concept of a difficult airway, but anything along the lines of the following will earn you the marks:
A clinical situation in which an anaesthetist experiences difficulty with facemask ventilation, supraglottic device ventilation, tracheal intubation or all three
More than two attempts at intubation using direct layngoscopy
Using adjuncts to direct laryngoscopy
Using an alternative device or technique following failed intubation with direct laryngoscopy
Remember that the Cormack and Lehane grades 3 and 4 relate to difficult laryngoscopy rather than a difficult airway.
What are the contraindications to awake fibreoptic intubation?
Patient refusal
Allergy to local anaesthesia
Stridulous patient or upper airway obstruction
Coagulopathy and epistaxis
Base of skull fracture
Penetrating eye injury
Inexperienced operator
What do the intrinsic muscles of the larynx do?
Cricothyroid - Tenses vocal cords
Thyroarytenoid and vocalis - Relax vocal cords
Lateral cricoarytenoid and transverse arytenoids - Adduction of cords
Posterior cricoarytenoid - Abduction of vocal cords
Which nerves innervate the vocal cords?
Recurrent laryngeal nerve supplies all the intrinsic laryngeal muscles with the exception of the cricothyroid muscle
It also supplies sensation to the subglottic mucosa
External branch of the superior laryngeal nerve supplies cricothyroid
The internal branch supplies sensation to the glottis, supraglottic region and inferior aspect of the epiglottis
How can you prepare the airway prior to awake fibreoptic intubation?
The airway needs to be topicalised with local anaesthetic, and optimised by drying secretions.
Glycopyrrolate 4 µg kg−1 IM one hour prior to intubation
- Not only does this reduce secretions but it also increases the effect of the local anaesthetic
- The IM route avoids the tachycardia and anxiety seen when given IV
Lidocaine up to 9mg/kg, often with a vasoconstrictor such as phenylephrine - as seen in co-phenylcaine
- This can be administered by nebuliser, using an atomiser as in the video in the post above, or through the scope itself
- Trans-tracheal injection of local anaesthesia is very effective for anaesthetising the cords and trachea
If you perform a trans-tracheal injection with a cannula and leave the cannula in situ, it can be also used for rescue oxygenation as well as guidewire insertion for an emergency tracheostomy if required.
What is the maximum acceptable dose of topical mucosal lidocaine and what percentage of nebulised lidocaine is systemically absorbed?
9mg/kg
20-25%
What are the predictors of difficult laryngoscopy?
This can be divided into patient factors and pathology factors:
Patient Factors
- Previous difficult intubation
- Neck immobility or instability - Rheumatoid Arthritis
and Ankylosing Spondylitis
- Obesity and acromegaly
- Previous airway surgery
- Previous neck surgery
- Congenital - Pierre-Robin, Treacher Collins, Down’s and Klippel-Feil syndromes feature in the Final FRCA rather frequently
Pathology Factors
- Infective causes
- Dental abscess
- Ludwig’s angina
- Epiglottitis
- Croup
- Neoplastic causes
- Tongue and oral tumours
- Laryngeal tumours
- Thyroid tumours and goitre
- Radiotherapy to mouth/neck - very strong
predictor
- Trauma
- Unstable cervical spine fracture
- Facial fractures
- Airway oedema
- Airway burns
What airway options are there for anaesthesia for airway stenting?
Endotracheal tube can be used for flexible bronchoscopy
Supraglottic airways can reduce coughing, while allowing easy access to upper trachea
THRIVE can be used for tubeless surgery
If using a rigid bronchoscope, usually remifentanil and propofol TIVA with jet ventilation
What are your primary airway concerns during airway stenting?
This is a shared airway, requiring clear communication between surgeon and anaesthetist
It may be difficult to maintain anaesthesia with inhalational agents
Airway loss could occur at any time
Conscious sedation with local anaesthetic topicalisation can reduce risk of airway loss in cases where flexible bronchoscopy is appropriate
THRIVE may be very helpful during sedation
If using general anaesthesia, relaxation of the trachealis muscle can precipitate obstruction, particularly in high grade and proximal lesions
How would you prepare a patient preoperatively for airway stenting?
MDT management - anaesthetist, respiratory team, thoracics, radiology
Oncology +/- palliative care team input
Understanding of ceiling of care and treatment goals
Informed consent, understanding of risks and benefits
Appropriate imaging - Multi-detector CT with 3D reconstruction
Understanding of what type of stent, and method of insertion (flexible bronchoscopy can be done under sedation)
Adequate rescue planning for airway management should complete obstruction occur
Optimisation of co-morbidities
Lung function testing and Echocardiography are often helpful
Which malignancies may require airway stenting?
Lung cancers
Lymphoma
Oesophageal
Thyroid
Sarcoma
Metastasis from external primary
What are the complications of airway stenting?
Early complications
- Airway obstruction
- Trauma due to bronchoscopy
- Barotrauma from ventilation
- Bleeding
- Air embolism
- Pneumothorax and tension pneumothorax
- Hypoventilation and hypoxia
Late complications
- Stent migration
- Stent breakdown
- Stenosis
- Erosion into surrounding tissue
- Chronic infection
- Granuloma formation
According to the RCoA what are the most valuable independent predictors of difficult facemask ventilation?
BMI over 26
Age over 55 years
Edentulous
Significant factial hair
History of snoring or sleep apnoea
What factors from the history and examination are of importance in an airway assessment?
Any previous problems with airway or anaesthesia
History of significant oesophageal reflux
History of sleep apnoea
Body mass index and presence of obesity
Mouth opening and inter-incisor distance
Mallampati score
Dentition and presence of loose teeth
Thyromental, sternomental or thyrosternal distance
Jaw protrusion
C spine mobility
Previous neck irradiation
What acronyms did Murphy and Walls come up with?
MOANS - difficult facemask ventilation
- Mask seal
- Obesity
- Age
- No teeth
- Snoring or stiff
RODS - difficult supraglottic airway insertion
- Reduced mouth opening
- Obstruction
- Distorted airway
- Stiff neck or lungs
LEMON - difficult intubation
- Look externally
- Evaluation - mouth opening <5cm, TMD <6cm
- Mallampati
- Obstruction
- Neck mobility
What factors on bedside examination would predict difficult laryngoscopy?
Receding jaw
Poor dentition
Short neck
Large tongue
Reduced neck mobility
Craniofacial abnormalities or trauma
Halo-thoracic brace
C spine collar
Stridor and difficulty swallowing secretions - evidence of obstruction
Stridor suggests that at some point between trachea and mouth, the airway is less than 4mm in diameter.
What are the components of the Wilson score?
BMI
Jaw protrusion
Neck mobility
Receding mandible
Buck teeth
What questions are we trying to answer with a preoperative airway assessment?
Any previous airway problems?
How easy is it going to be to facemask ventilate?
How easy is it going to be to use a supraglottic airway?
How easy is it going to be to intubate?
How likely are they to aspirate?
Will they be a safe extubation?
Any respiratory disease?
Is the surgery likely to impact on the airway?
How is atlanto-axial subluxation classified?
Anterior - 80% (loss of transverse ligament integrity)
Vertical - 10% (destruction of lateral masses of C1)
Posterior - 5% (destruction of odontoid peg)
Lateral - 5% (destruction of C1/C2 facet joints)
