Frequently asked questions for owners: Therapeutic plasma exchange
Fact File
What is therapeutic plasma exchange?
Therapeutic plasma exchange (TPE) is a procedure that can be performed to remove plasma from a patient in order to clear substances that may be present in the plasma and harmful to that patient. To perform TPE a patient will usually have a large catheter placed. Blood is drawn out of the catheter into a circuit and is then processed either across a filter (membrane TPE) or by spinning (centrifugal TPE). The patient’s plasma is removed and plasma from a healthy donor is used as a replacement with blood then returned to the patient. TPE can remove a number of important molecules including antibodies (immunoglobulins) and also some toxins.
Why might my vet recommend therapeutic plasma exchange?
TPE can be recommended for a number of conditions where the immune system attacks the body, for example immune mediated haemolytic anaemia (destruction of the red blood cells), immune mediated thrombocytopenia (destruction of the platelets, important cells for clotting) and myasthenia gravis (immune attack on the neuromuscular system). TPE can also be used to remove some drugs or toxins that are too large to be removed by dialysis. It has also been used to treat some dogs that have been presented with cutaneous renal glomerular vasculopathy (CRGV) or as it has more colloquially been termed ‘Alabama rot’.
My dog has immune mediated disease, can he/she have TPE?
We typically preserve TPE for dogs that are either not responding to normal medical treatment for their immune mediated disease or where there is a reason that they should not be treated with immunosuppressive drugs. If you think that your pet could benefit from TPE then please speak to your veterinary surgeon and ask them to get in touch with us directly to discuss their case and whether TPE could be of benefit.
My dog has had a drug overdose or has ingested a substance that is likely to cause adverse effects, can she/he have TPE?
Many drugs can have side effects if overdosed; this often happens accidentally and can include situations where your pet has ingested a medication you had at home or if he/she has been administered a medication at a dose higher than required. These drugs can be removed with TPE if referral is done in a timely fashion before the drug has redistributed in the body and is still present in the blood. Every drug behaves in a different way but if the dose is high enough to cause severe toxicity and can be removed, TPE can be considered. We would advise to speak to your veterinary surgeon and ask her/him to get in touch with us directly to discuss their case and whether TPE could be of benefit at that stage.
Where does the donor plasma come from?
The RVC Small Animal Referrals has a busy blood donation programme for both dogs and cats. Most of the time, the blood donation service are preparing packed red blood cells for dogs who are anaemic. However, one of the by-products of the blood donation service is plasma – the liquid component of blood! There are lots of instances where we need to give plasma to dogs but one of them is as replacement plasma for dogs undergoing TPE.
How many TPE treatments would my dog have?
The number of TPE treatments performed depends on the underlying condition and also response to treatment. In some dogs only one treatment will be performed but it is more common for two or three cycles to be required usually on an every other day basis.
How much does TPE cost?
TPE is an involved procedure which is usually performed by our Extracorporeal Therapy Team in conjunction with the Emergency and Critical Care Team and will form just part of the overall care package that your pet receives. If TPE is recommended for your pet then we will take time to talk to you specifically about the costs of this procedure and the ongoing care that your pet will need.