Anaesthesia for Thyroid and Parathyroid Surgery

Question 1

Intraoperative neuromonitoring for thyroid surgery

Answer 1

• Tracheal tube with surface electrodes applied to the tube’s surface. This sits between the vocal cords.
• If the recurrent laryngeal nerve innervates the vocalis muscle to contract then the electrodes will record the amplitude and latency of this impulse as a graphic wave and sound.

Question 2

Options for NMBDs in thyroid surgery

Answer 2

• No NMBD
• Suxamethonium
• Cisatracurium
• Rocuronium and sugammadex (or low dose sugammadex combined with neo/glyc)

Question 3

Risk factors for difficult airway in thyroid surgery

Answer 3

• Male
• BMI >30
• Mallampati >3
• Incisor gap < 4.5cm
• Neck circumference >40 cm
• Goitre
• Signs & symptoms of tracheal compression

Question 4

What drugs does a patient in a myxoedema hypothyroid coma require if having emergency thyroid surgery?

Answer 4

• Loading dose of IV levothyroxine 200-500mcg
• Followed by 50-100mcg OD
• IV T3 should be available
• Patients may require steroid cover

Question 5

Perioperative considerations for the hypercalcaemic patient requiring urgent parathyroid surgery
- Hypercalcaemia resistant to medical management
- Pregnant patients
- Recurrent renal stones

Answer 5

Pre and Intra-op risk of hypercalcemic crisis
- Needs to be well hydrated with IV fluids
- Consider denosumab, calcitonin, bisphosphonates etc.
- Reduced dose of NMBD

Post-op hypocalcaemic collapse
- Sudden CV collapse will require vasopressors and fluid
- Arrhythmias esp long QT
- IV calcium

Question 6

Post-op complications after thyroid surgery

Answer 6

• Bilateral recurrent laryngeal n palsy- re-intubate
• Post-op haematoma- Oxygenate-> Evaluate -> Evacuate -> Intubate
• Acute post-op hypocalcaemia- Calcium gluconate 2g bolus followed by infusion