Anesthesia for total laryngectomy

Total laryngectomy is the removal one or more of the laryngeal structures including the epiglottis,hyoid,and a variable amount of upper trachea with selective neck dissection which aims to remove a portion of nodes most at risk of metastasis.
PREOPERATIVE ASSESSEMENT
Standard preliminary investigations with stress on Hb levels, anaemia if present should be optimised.Most patients may require grouping and saving of blood but pre-op transfusion is rare.
Comorbid health conditions: 1) Ischaemic Heart Disease is a frequent comorbidity and cardiology opinion has to be sought if unstable angina,recent stenting,decompensated heart failure or severe aortic stenosis.
2) Respiratory Disease Laryngectomy patients are frequent smokers.Thorough evaluation of the respiratory system with associated imaging studies, if laryngeal narrowing is significant then Pulmonary Function Tests are not very reliable If Pulmonary Hypertension and Right Heart Failure are associated then serious consideration to optimise as they fall under high risk category.
Dynamic assessment of the functional status of the cardiopulmonary status of the patient can be evaluated with the estimation of METS score if < 4 then associated with increased risk
Preoperative Optimisation Majority patients are chronic alcoholics and smokers, careful planning and optimisation to proceed  1 to 2 weeks ahead of surgery is warranted.Hospital admission and controlled alcohol withdrawal with NG feeding to improve nutrition.Smoking cessation.
Risk Stratification Discussion about risk and consent to be obtained on individual needs
Planning of airway Management
Airway Assessment
History Taking in detail with emphasis on voice change, dysphagia,breathlessness and stridor . if the patient can lie flat? and if he get"s up in sleep due to breathlessness?
Bedside examination: The patients natural resting position is to be noted.
 Airway assessment usual mouth opening, tongue protrusion, mallampati scoring, thyro-mental distance, neck movement is done
Neck Examination  For neck masses, any previous radiotherapy, tracheal deviation, previous scars.
Any anticipated difficulty with front of neck access should be noted
Imaging CT and MRI are the mainstay of preoperative imaging, The axial sections can be used to see the narrowing of airways and the coronal sections are used to estimate the length of narrowing.
Nasendoscopy imaging can be done prior to the airway management with the surgical team to note any points of narrowing, rigidity or fragility of tissue, or the presence of tumour which may obscure the laryngoscopic view.
Thorough evaluation is done in view of the following steps
Preoxygenation
Positioning the patient in the most restful position
High Flow Nasal Oxygenation (HFNO) as a means to pre oxygenate and apnoiec ventilation until definitive airway is obtained has been highlighted  in the Transnasal Humidified Rapid-insufflation ventilator exchange(THRIVE) study and is widely used. It can provide CPAP. If conventional Nasal prongs are used than can be augmented with face mask (NODESAT) technique
Preinduction 
These patients are always induced in OT table in presence of consultant surgeon
A anaesthesia and surgical briefing is done and planA,B,C and D is discussed, prepared and written on white board so all members of the team are prepared.
Awake intubation or conventional induction depends on the ease of attaining a definitive airway
Video-laryngoscopy has been the first line of choice in DAS guidelines for laryngoscopy
Awake Fibre-Optic intubation (AFOI) is the method of choice in supraglottic obstruction as in epiglottis and tongue base obstuction
In patients with critical narrowing of laryngeal inlet the AFOI is of lesser use as because of

• Topicalisation is difficult and there is Copious Secretion 
• Sedation has be used very judiciously as maintenance of spontaneous ventilation is needful
• "Cork in the Bottle" analogy as the critical narrowing is completely closed with the introduction of the FOB scope and the airway is lost.

FONA Front of neck access is ideal in the above conditions. Trantracheal cannulation for jet ventilation which can later be converted to tracheostomy if needful.Prior assessment of neck for FONA with landmarking and LA infiltration and prior ascertaining of who will perform FONA  can buy time in hour of need.The choice of cricothyroidectomy or tracheostomy is a individualised.

Perioperative Management

Monitoring

Standard monitors with invasive blood pressure monitors to assess the fluid and blood chemistry as the surgery is usually long and blood loss is anticipated.

Urinary Catheter and temperature probe.

Short acting agents are preferred due to long duration to allow early emergence

TIVA is preferred as there is loss of volatile anaesthetic during surgery

Meticulous care in positioning to avoid pressure points

Post operative care

Admission into HDU with team handlingl aryngectomy patients

Pain management with judicious use of opioids and NSAIDS and Patient controlled Analgesia

Patients are stepped down to specialist wards in the next 48hrs.