FRCA Notes

Anaesthesia for Head & Neck Cancer Surgery

This section is included as a summary of the relevant BJA Education article (see below), without there having been an SAQ/CRQ question specifically on the topic.

The perioperative principles carry forward to a number of ENT procedures, including laryngectomy.

Resources

  • Head and neck cancer can occur at a number of sites, including:
    • The aerodigestive tract
    • The paranasal sinuses
    • Within thyroid and salivary glands
  • There is a 10% risk of a synchronous primary lesion elsewhere in the aerodigestive tract
  • The usual list of vices can land you with head and neck cancer, including:
    • Tobacco, be it smoked or chewed
    • Cannabis (JAMA, 2024)
    • Excessive alcohol consumption
    • Poor oral hygiene
    • Wood dust inhalation
    • HPV infection
  • Non-modifiable risk factors include male gender and age >55yrs

Perioperative management of the patient booked for head and neck cancer surgery


  • In general there may be narrowed timeframes for pre-operative assessment and optimisation, and one should be mindful of avoiding unnecessary delays to definitive treatment

Airway assessment

  • Unsurprisingly there is a higher incidence of difficult airway management than the general population
  • History and examination
    • Subtle changes to voice, dysphagia, orthopnoea, recent onset snoring indicate airway compromise
    • Dyspnoea and overt stridor may also be present
    • In slowly progressing Ca, there may be few symptoms or signs despite significant airway narrowing

    • A standard airway examination should take place, noting patient's preferred position (sitting bolt upright may indicate positional dyspnoea) and assessing feasibility of FONA
    • Prior treatment with radiotherapy can result in a 'fibrotic' or 'woody' airway, or a 'frozen' larynx

  • Imaging
    • Review CT or MRI to help determine impact of the pathology on the airway and the potential obstruction, bearing in mind the disease may have progressed since the time of the imaging
    • Ultrasound can be used to identify the cricothyroid membrane prior to induction of anaesthesia
    • Awake nasendoscopy to give real-time view of upper airway and larynx

Respiratory disease

  • COPD is common and should be optimised before surgery
  • Smoking cessation should be encouraged
  • Lung function tests and flow-volume loops can help differentiate dyspnoea due to COPD vs. upper airway obstruction
    • If there is significant airway narrowing e.g. from laryngeal cancer then lung function tests may be unreliable

Cardiac disease

  • On account of protracted smoking history and potential for cor pulmonale, cardiovascular disease is commonplace
  • CPET would be beneficial but often patients are not suitable for CPET owing to the dyspnoea they experience from their upper airway obstruction
    • CPET's utility has not yet been clearly demonstrated in head and neck cancers
    • Other measures of functional capacity e.g. DASI can be useful
  • Heart failure, in particular NYHA class III or IV and RHF patients with pulmonary HTN, carries a poor prognosis

Nutritional assessment

  • Malnutrition independently correlated with poor wound healing, infection and risk of post-op. complications
  • Malnutrition may occur due to:
    • Poor dietary habits inc. alcohol intake (consider pre-operative detoxification)
    • Dysphagia
    • Cancer cachexia
    • Systemic effects of neo-adjuvant therapy e.g. radiation mucositis

  • Patients should undergo pre-operative screening and specialty dietetic input
  • Nutritional therapy is indicated if:
    • BMI <18.5kg/m2
    • Weight loss >10%
    • Inadequate oral intake likely after surgery
  • Patients are at risk of refeeding syndrome and should be monitored/treated accordingly
  • Pre-operative PEG insertion is rarely performed, as often the goal is to rehabilitate swallowing - temporary enteral feeding via NG tubes is suitable

Investigations

  • Bloods
    • FBC - treat preoperative anaemia
    • U&Es
    • LFTs
    • Clotting screen
    • Group and save - excessive bleeding is uncommon so cross-match is usually unnecessary

  • 12-lead ECG
  • ± CXR
  • ± TTE
  • Spirometry/lung function test, either alone or as part of a measure of functional capacity

Risk stratification

  • P-POSSUM, SORT and ACS-NSQIP do not accurately predict risk in head and neck cancer patients
  • The 2016 UK multidisciplinary head & neck cancer guidelines recommend using the Revised (Lee) Cardiac Risk Index to predict cardiac risk in the perioperative period
  • The overall risk a 30-day cardiac event is 1-5%

Monitoring

  • AAGBI as standard
  • ± A-line due to cardiovasculr disease
  • Wide-bore cannula after induction, especially if planned dissection around the carotid sheath
  • ± CVC, though often not required
  • Depth of anaesthesia monitoring

Induction

  • Airway difficulty is to be expected and should be planned for, including FONA
  • Inhalational induction has been shown to frequently fail and, if used, a rescue plan is required

  • One should have a low-ish threshold for using an awake tracheal intubation technique, especially if:
    • Bag-mask ventilation is predicted to be difficult, or has previously failed/been difficult
    • Intubation is predicted to be difficult, or has previously failed/been difficult
  • ATI benefits from maintenance of airway patency, gas exchange, and protection against aspiration during the intubation process
  • It may not be feasible e.g. due to significant obstruction or other contraindications; in such cases consider awake tracheostomy

  • A TIVA technique is often preferred owing to the uncoupling of airway and anaesthetic maintenance, as well as the benefits of remifentanil in these patients

Positioning & padding

  • Eye tape and shields (inc. moistened pads for LASER procedures)
  • Supine but 15-20° head-up tilt to improve venous drainage
  • Meticulous padding, as can be long procedures and patients may be at higher risk due to cachexia and poor peripheral perfusion

Homeostatic bundle

  • Temperature monitoring and suitable warming
    • Peripheral probe e.g. bladder or rectal to avoid probe interference with surgical field
    • In free flaps, measure skin and bladder temperatures to ensure core-periphery gradient <1.5°C
  • VTE prophylaxis e.g. TEDS ± IPCs
  • Antibiotic prophylaxis

  • Multi-modal anti-emesis
  • Multi-modal, opioid-sparing analgesia

  • Surgical tracheostomy is frequently required, as otherwise oedema can lead to airway compromise
  • Benefits include:
    • Secure airway
    • More effective bronchial toilet/suction
    • Reduced dead space helps wean from mechanical ventilation
  • Naturally this means HDU, ICU or a suitably staffed/monitored head & neck ward is required post-operatively