Vascular Access Surgery

Question 1

A 59-year-old female patient is listed for creation of an arterio-venous fistula for pre-emptive renal replacement therapy. She has a history of hypertension, type 2 diabetes mellitus and a raised BMI.

What are the most common causes of chronic kidney disease?

Answer 1

• Diabetes mellitus.
• Glomerulonephritides.
• Pyelonephritis.
• Chronic hypertension.
• Polycystic kidney disease.
• Renal vascular disease.

Question 2

What are the options for renal replacement therapy in patients with end-stage renal failure?

Answer 2

• Continuous ambulatory peritoneal dialysis.
• Haemodialysis.
• Renal transplant.

Question 3

What is disequilibrium syndrome?

Answer 3

• Disequilibrium syndrome is a collection of symptoms that may occur in new haemodialysis patients, including headache, visual changes, nausea and vomiting, confusion, agitation, seizures and coma.
• It is thought to occur due to rapid changes in serum urea and electrolyte levels, which may lead to cerebral oedema and rapid signs of neurological changes.
• New dialysis patients should be carefully assessed and monitored, and their treatment protocols increased gradually to avoid the development of disequilibrium syndrome.

Question 4

You are asked to review this patient prior to her procedure.

What are the key aspects in her history that will determine perioperative management?

Renal disease…?

Answer 4

Renal disease:
* The duration and any previous treatment should be determined, including any earlier procedures for renal replacement therapy. If the patient has had a renal transplant, her immunosuppressant status should be noted and discussed with the renal team prior to her anaesthetic.

• The cause of the patient’s renal disease should be established as it may impact on care during the perioperative period.

Question 5

What are the key aspects in her history that will determine perioperative management?

Comorbidities…?

Answer 5

• A history of hypertension may predispose the patient to ischaemic heart disease or peripheral vascular disease. A thorough cardiac history should be taken including any ischaemic events or symptoms suggestive of cardiac failure.
• Given the history of type 2 diabetes mellitus and end-stage renal failure, both micro- and macro-vascular complications are likely. These should be explored, together with current compliance with treatment and blood sugar control.
• The patient’s weight will have both physiological and practical implications during the perioperative period, due to the associated comorbidities, anaesthetic procedural challenges and the risk of postoperative complications.
• Renal dysfunction will predispose her to electrolyte imbalance, clotting dysfunction and a normocytic chronic anaemia that will need to be checked prior to an anaesthetic.

Question 6

What are the key aspects in her history that will determine perioperative management?

Drug History…?

Answer 6

• Anti-hypertensive medications such as ACE inhibitors may need to be stopped prior to her procedure to minimise the risk of significant perioperative hypotension.
• Hypoglycaemic agents may need regimens tailored during the perioperative period.
• Immunosuppressive agents should be continued.

Question 7

How would you anaesthetise this patient?

Answer 7

• Ensure AAGBI monitoring, resus equipment, difficult airway trolley and emergency drugs are readily available.
• Given the patient’s comorbidities and the type of surgery, a regional anaesthetic would minimise the risks associated with a general anaesthetic. In addition, a nerve block is often favoured by the surgeons due to its vasodilatory effects improving fistula patency during the perioperative period.
• A regional nerve block also avoids the challenges of agent choice and dosage for anaesthesia and analgesia, which need to be modified in patients with end-stage renal failure.
• Sedation can also be offered to the patient, carefully titrated to avoid the risk of respiratory depression and airway obstruction.

Question 8

You carry out an axillary nerve block. 40 minutes into the procedure, the patient is complaining of discomfort. How do you proceed?

Answer 8

• Alert the surgeons and ask them to stop as soon as feasible.
• Determine the location and type (e.g. pain and pressure) of discomfort.
• If the discomfort is felt in the arm, ask the surgeons to inject local anaesthetic at the site of discomfort.
• Administer intravenous analgesia, cautious of respiratory depression
  with opiates.
• If discomfort persists at all stages, offer a general anaesthetic; risks
  to be discussed with the patient and a senior alerted for help with induction if necessary.
• Document actions and assess the patient in recovery and on the ward
  following their procedure.