FRCA Notes

Anaesthesia for Laryngectomy

This topic has yet to appear as a CRQ/SAQ. It is, in essence, a sub-section of the management of patients with head and neck cancer.

Resources

  • Total laryngectomy involves removal of the larynx, epiglottis, hyoid bone and upper trachea, with subsequent formation of a tracheostome
  • Additional surgical steps include:
    • Neck dissection (selective, radical)
    • Pharyngeal reconstruction using local, pedicled or free flaps
  • Partial laryngectomy (vertical partial, supra-cricoid) may be performed instead

  • Total laryngectomy is performed for T4 laryngeal cancer either as:
    • A primary intervention
    • Following failure of laryngeal-preserving treatment i.e. radio-/chemo-therapy for less advanced cancer (i.e. T3 or less)
  • It is an effective treatment with good functional outcomes
  • Accounts for <1% of new cancer diagnoses
  • Male preponderance (4x)
  • Associated with smoking and alcohol consumption
  • Patient cohort is often older with other co-morbidities

Perioperative management of the patient undergoing elective laryngectomy


  • The astute will notice this is essentially the same as for any head and neck cancer patient
  • 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
  • Arterial line often prudent due to cardiovascular disease, long surgeries and limited access
  • CVC rarely necessary, although if significant vascular access issues due to previous chemotherapy then it may be required
  • Temperature monitoring
  • Urinary catheter
  • ± Depth of anaesthesia monitoring

Airway choices

  • Although intubation may be difficult, it is preferred to avoid pre-operative tracheostomy, as this is associated with poorer wound healing and higher recurrence rates
  • Initial intubation is with an appropriately-sized armoured tube
  • At the time of tracheostome formation, this tube is withdrawn and a laryngectomy ('J' tube or Montandon tube) is inserted for the remained of the case
  • At the end of the procedure, the laryngectomy tube is removed and replaced with either a tracheostomy or the tracheostome is left un-intubated

Anaesthetic technique

  • A TIVA technique is often used as it uncouples the airway from maintenance of anaesthesia (and venting of volatile agent into the surgeon's faces during tracheal dissection)
  • Generally non-paralysed patients are preferable, so use of remifentanil TCI and other suitable agents (e.g. IV lidocaine at induction) is common

Homeostatic bundle

  • Appropriate warming/temperature control
  • Meticulous pressure care and positioning as long surgery in patients who often has risk factors for pressure sores e.g. malnutrition, vascular insufficiency

Analgesia

  • Regular simple analgesia with paracetamol; NSAIDs are often relatively contraindicated
  • Short-acting intra-operative and post-operative agents are preferable e.g. fentanyl IV, oral morphine
  • There may be variable amounts of surgical-site hypoaesthesia/anaesthesia depending on whether the branches of the superficial cervical plexus are preserved

Disposition

  • Patients will require 24 - 48hrs in a level 2 environment before step-down to a ward experienced in the management of such patients

  • Bleeding due to vascular injury during neck dissection
  • Thoracic duct injury and chylothorax
  • Raised ICP e.g. due to internal jugular vein ligation
  • Nerve palsies:
    • Marginal mandibular branch of the facial nerve - lower-lip weakness
    • Hypoglossal nerve - loss of movement of the ipsilateral tongue
    • Accessory spinal nerve - stiffening and weakness of shoulder movements
    • Phrenic nerve - ipsilateral paralysis of the hemidiaphragm