Therapeutic plasma exchange (TPE) in dogs is indicated for immune-mediated diseases, toxicoses involving highly protein-bound substances, and hyperviscosity syndromes, with emerging use in polyradiculoneuritis and immune-mediated thrombocytopenia (IMT). In cats, TPE has been reported for acquired myasthenia gravis. Journal of Vete…+4

Indications

NSAID toxicosis is the best-characterized toxicological indication for TPE in dogs. TPE is particularly effective for substances with high protein binding (>80%) and low volume of distribution (<0.2 L/kg), properties shared by naproxen, ibuprofen, carprofen, and meloxicam. Journal of Vete… Single-session TPE produces an 82% reduction in plasma meloxicam concentration, an 85% reduction in ibuprofen concentration, and a 51% reduction in carprofen concentration. Journal of Vete… In a 62-dog multicenter cohort treated with TPE for NSAID overdose, the overall survival rate was 98.4%, and 91.1% of dogs with follow-up were not azotemic at recheck. Journal of Vete… Despite 74.2% of those dogs ingesting a neurologically toxic dose, only 8% exhibited observable neurological signs during hospitalization. Journal of Vete… TPE is also effective for naproxen, which carries a prolonged elimination half-life of 74 hours in dogs; a 2-plasma-volume TPE exchange produced a 46% decrease in blood naproxen concentration, and a subsequent plasmaperfusion session produced an additional 10.3% decrease. Journal of Vete…+1

Immune-mediated diseases represent the other major indication class. TPE has been applied to immune-mediated hemolytic anemia, IMT, and thymoma-associated myasthenia gravis. Veterinary Reco…+2 In four dogs with IMT that were unresponsive to conventional treatment or presented with severe hemorrhage, three sequential centrifugal TPE sessions totaling 4.0–4.9 total plasma volumes per dog were associated with improvement in clinical bleeding and platelet count in three of four dogs. Journal of Vete… In a cat with thymoma-associated myasthenia gravis, two TPE sessions performed 4 and 8 weeks post-thymectomy produced clinical improvement after each session; improvement was short-lasting after the first and long-lasting after the second, with the cat remaining in clinical remission 32 months post-thymectomy. Veterinary Reco…

Acute canine polyradiculoneuritis is an emerging indication. A single manual TPE session in a dog with flaccid tetraplegia and respiratory compromise was safe and well tolerated, with neurological improvement from grade 4 to grade 3 tetraplegia within 5 days. Acta Veterinari…

How TPE Is Performed

Plasma separation is achieved by either membrane filtration or centrifugation. Membrane-based TPE (mTPE) uses hollow-fiber plasma filters within a multifunctional blood purification platform and is more widely available in veterinary medicine; centrifugal TPE (cTPE) requires specialized machines available only at select institutions. Journal of Vete…+1 Manual TPE — sequential phlebotomy, centrifugation at 5,000 × g for 8 minutes, plasma removal, and autologous red cell return with replacement fluid — is a lower-technology alternative reported in dogs. Journal of the…+1

Plasma volume exchanged is prescribed based on the patient's plasma volume (PV) and the desired degree of substance removal. Using first-order kinetics, 1.0, 1.5, and 2.0 PV exchanges are expected to reduce a target substance by approximately 63%, 78%, and 86%, respectively. Journal of Vete… Exchanges exceeding 2.0 PV produce smaller, less clinically relevant decreases while increasing cost and transfusion exposure. Journal of Vete… In the 62-dog NSAID cohort, the median plasma volumes processed per session was 1.6 (range, 0.4–2.2), with a median session duration of 2 hours (range, 1–4.5 hours). Journal of Vete…

Replacement fluid selection requires careful consideration in dogs. Fresh frozen plasma, colloids, human albumin, and saline have all been used in various combinations. Journal of Vete… Human albumin is associated with anaphylactoid reactions, serum biochemical abnormalities, severe edema, and anti-albumin antibody production in dogs and is therefore not preferred. Journal of the… A dilute hetastarch solution (3%) has been used as an alternative replacement fluid. Journal of the…

Anticoagulation is required for all extracorporeal circuits. Regional citrate anticoagulation is the most commonly used protocol; systemic heparinization and combined approaches have also been employed. Journal of Vete… Citrate accumulation occurs in all dogs undergoing TPE, and is more pronounced in dogs with renal impairment. The maximal tolerable citrate rate is 5.5 μmol/kg/min in dogs with renal impairment and 9.0 μmol/kg/min in dogs without renal impairment. Journal of Vete…

Vascular access must support high blood flow rates for both collection and return phases. Options include peripheral venous access, central venous catheters, tunneled central venous catheters with ports, and arteriovenous grafts or fistulas. Transfusion Patients requiring multiple sessions over days to weeks particularly benefit from dedicated central venous access. Transfusion

Complications and Outcomes

Complications occur in approximately one-third of TPE sessions in dogs. In the 62-dog NSAID cohort, adverse events were reported during 33.8% of sessions, consisting of urticaria (12.9%), asymptomatic hypocalcemia (9.6%), and hypotension (9.6%); circuit clotting occurred in 12.9% of sessions. Journal of Vete… In a 64-treatment membrane-based TPE series, complications were observed in 34% of treatments and were fatal in 2 dogs. Journal of Vete… Expected laboratory changes after a 1.0 PV exchange include a 24.7% decrease in total protein, 53% decrease in fibrinogen, 36% decrease in bilirubin, 9.0% decrease in urea, and 4.5% decrease in creatinine. Journal of Vete…

Overall NSAID toxicosis prognosis in dogs is excellent regardless of treatment modality. Across 434 dogs treated with intravenous fluids (IVF), intravenous lipid emulsion (ILE), or TPE, the overall survival rate was 99%. Journal of Vete… Dogs treated with IVF + ILE had a lower median maximal creatinine (0.9 mg/dL) compared with IVF alone (1.1 mg/dL). Journal of Vete… Increased time to presentation, higher baseline creatinine and packed cell volume, and absence of induced emesis were associated with greater clinical severity. Journal of Vete…

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