What is dialysis and what is it used for?

Dialysis is a method of purifying the blood of toxins that are normally cleared by the kidneys. We use dialysis to help support dogs and cats when they have sustained an acute injury to their kidneys and are suffering from acute kidney failure. In humans, dialysis is used for patients with chronic kidney disease to support them until a kidney donor is available for transplantation. We are not able to offer dialysis for dogs and cats with chronic kidney disease and transplantation is not possible in the UK.

What is acute kidney injury?

The kidneys are important for removing toxins and waste products from the body, they produce urine and keep electrolyte levels stable. Acute kidney injury means that the kidneys have been damaged suddenly. Acute kidney injury can occur for a number of reasons, for example exposure to toxins such as anti-freeze, grapes (dogs), lilies (cats), drugs and infection (leptospirosis). However, unfortunately in a lot of dogs and cats we never find out exactly what causes their acute kidney injury. In acute kidney failure the kidney is no longer able to get rid of waste products. These waste products build up making the dog or cat feel very unwell. In some patients with acute renal failure urine production stops and fluid accumulates in the body. Retention of fluid, high levels of toxins and electrolytes (potassium) can become a life threatening situation.

How is acute kidney failure treated?

Less severe acute injury to the kidney can be treated medically. Your vet may suggest careful monitoring, drugs (e.g. diuretics) and fluid therapy or may suggest referral to a hospital for this care. For dogs and cats with severe acute kidney failure medical treatment may not be enough and in this situation a decision may be necessary to consider dialysis treatment or euthanasia.

What exactly happens when a dog or cat has dialysis? 

In order to perform dialysis we place a large cannula or catheter into the jugular vein (large vessel in the neck). Blood is then circulated from the patient through a circuit and a filter in the dialysis machine. The filter is specially designed to remove toxins that would normally be removed by the kidney. Having been cleaned, blood is then returned back to the patient. In total, a single treatment usually takes between 6-8 hours. Whilst dogs and cats are receiving dialysis they will, at least initially, remain in hospital in the intensive care unit so that we can monitor them very carefully. We will typically perform dialysis every other day and check carefully for signs that the kidneys are starting to work again.

How do I get dialysis for my dog or cat? 

If you think that your dog or cat would benefit from dialysis you should speak directly with your primary care veterinary surgeon. The Emergency and Critical Care team at the RVC Small Animal Referrals is able to offer advice 24 hours a day 7 days a week and can speak directly with your veterinary surgeon to determine whether referral for management of acute kidney failure and dialysis would be appropriate.

How much does dialysis cost?

The time and care that your pet will receive during dialysis means that this is an expensive procedure. When we speak to your veterinary surgeon we will be able to give an initial estimate for your pet’s care and should your dog or cat come to the hospital we will discuss costs with you at every step. 

What are the outcomes for my pet?

The outcome for dogs and cats with acute kidney failure depends on the underlying cause. If a treatable cause can be found then prognosis can be reasonable. However, overall the survival of cats and dogs exposed to toxins or where we do not find a cause is often <50%. Sadly, if we feel that your pet is not showing signs of improvement in their kidney function, then, even if we perform dialysis, we may ultimately recommend you consider euthanasia.