Anaesthesia for Head and Neck Cancer Surgery
Highlights
- Patients with anaerobic threshold less than 11 ml min−1 kg−1 are at a higher risk of cardiac complications (View Highlight)
- Nutritional therapy is indicated if the BMI is less than 18.5, weight loss greater than 10% of body weight, or if inadequate food intake is likely after surgery (View Highlight)
- The theoretical advantage of gas induction is that it is a slow induction that preserves spontaneous ventilation, and if at any point airway obstruction does occur, then the delivery of the inhaled anaesthetic ceases and the patient can theoretically wake up. The NAP-4 report highlighted that, in practice, when total airway obstruction occurs, patients do not exhale the anaesthetic gases and hypoxia rapidly ensues (View Highlight)
- In free flap transfer, both the skin and the core bladder temperatures are measured to ensure that the core–periphery gradient is less than 1.5°. (View Highlight)
- Submental intubation for improved access to the oral cavity is an absolute contraindication in cancer surgery because of the risk of creating an orocutaneous fistula. (View Highlight)
- Free flap transfer
The aim of anaesthetic management is to maintain a full, hyperdynamic circulation with increased cardiac output, peripheral vasodilation, and normothermia to maximize flap perfusion. The haematocrit is maintained at 30–35% to improve oxygen transfer and red cell velocity within the microcirculation (View Highlight)
- The absolute contraindications for free flap transfer are sickle cell disease and untreated polycythaemia rubra vera, because flap failure rate is high from microcirculatory ‘sludging’ and hypercoagulability. The incidence of anastomotic thrombosis is high in patients with active vasculitis associated with collagen vascular disease; therefore, specialist referral and treatment is indicated before surgery. With peripheral vascular disease, magnetic resonanace angiography is indicated to determine patency of donor vessels in the fibular flap for mandibular reconstruction (View Highlight)
- Other complications of thyroid surgery include postoperative hypocalcaemia and tracheomalacia in long-standing tracheal compression (View Highlight)
- The aims of postoperative care in free flap surgery are maintenance of normotension, normothermia with adequate filling, and regular monitoring of the flap. The haematocrit should be maintained at 30–35% (dextran and aspirin are no longer given because of lack of proof of efficacy). Nutritional support should be commenced as soon as possible after surgery (View Highlight)