Membrane‐based therapeutic plasma exchange in dogs: Prescription, anticoagulation, and metabolic response

Abstract

Background Therapeutic plasma exchange (TPE) is used increasingly in small animals to remove circulating large molecular products such as antibodies, pathogenic proteins, and protein‐bound toxins. Specific, efficient, and safe protocols need to be developed. Hypothesis/Objectives To describe the technique of membrane‐based TPE, the resulting physiological and metabolic changes, and to define an adequate regional citrate anticoagulation protocol. Animals Thirty‐four dogs treated with TPE (2011‐2017). Methods Retrospective review of all TPE treatments performed at the Vetsuisse Faculty, University of Bern, identified through a search of the institutional database for extracorporeal treatments. Results Sixty‐four treatments were performed, resulting in 1.0 plasma volume exchange (range, 0.4‐1.1). Replacement fluids included fresh frozen plasma (12%‐100% volume), colloids (0%‐52%), human albumin (0%‐41%), and saline (0%‐70%). Anticoagulation was performed with regional citrate (n = 24), systemic heparinization (n = 2), or combined (n = 38). Main relevant laboratory changes included a 24.7% decrease in total proteins (interquartile range, 16.7‐31.4; P < .001), 53% in fibrinogen (−30 to 63; P = .009), 36% in bilirubin (13‐43, P = .02), 9.0% in urea (0.7‐15.7; P < .001), and 4.5% in creatinine (−6.6 to 10.6; P = .006). Citrate accumulation was evidenced in all dogs, more pronounced in those with renal but not with hepatic impairment. Maximal tolerable citrate rates were estimated as 5.5 and 9.0 μmol/kg/min for treatments in dogs with and without renal impairment, respectively. Complications were observed in 22 treatments (34%) and were fatal in 2 dogs. Conclusions and Clinical Importance Therapeutic plasma exchange causes metabolic and biochemical alterations. Understanding these effects makes possible to anticipate most complications and to improve safety of the procedure.

Treatment of a flunixin meglumine overdose with intravenous administration of lipid emulsion and therapeutic plasma exchange in a Nigerian dwarf buck kid (Capra aegagrus hircus)

“…Thus, the benefits of this treatment modality were exceeding the risk of potential complications described with mTPE. 12,17 Comparing mTPE for goats against that of dogs, 3 major differences were identified: At the outset, acquiring fresh plasma from goats would likely be an impediment to the procedure, which is not presented for mTPE in dogs. For our goat, the return of fresh plasma was made possible by collection from goats in the institutional herd.…”

“…This formulation of replacement fluid has been successfully used in dogs. [9][10][11][12]17 Fresh plasma was collected from donor goats in the insti- The session was initiated 4 hours after the overdose had occurred. The goat's ACT prior to the mTPE was 99 seconds (reference interval: 91 ± 3 seconds) and served as a baseline measurement.…”

Evaluation of membrane‐based therapeutic plasma exchange as adjunctive treatment for immune‐mediated hematologic disorders in dogs

“…The centrifugation technique allows a higher plasma extraction fraction than the filtration technique and thus it necessitates a lower access blood flow rate, shorter procedure times, and a lower risk of citrate accumulation when used for regional anticoagulation. As demonstrated previously however, RCA can be used in dogs as the sole mode of anticoagulation in mTPE when necessary, with only minimal to moderate citrate accumulation that has no negative clinical consequences for the animal 4 …”

“…Blood purification techniques have gained new interest with the broader availability of modern multifunctional systems. 4 Large volumes of plasma can now be removed and replaced at least partially with fresh plasma, a procedure more specifically designated as therapeutic plasma exchange (TPE). Most of these treatment recommendations are based on low-grade evidence.…”

Immunoadsorption in a dog with severe immune mediated hemolytic anemia

“…Canine plasma, used as a replacement fluid, is a rare resource in many countries, which limits the application of TPE. Potential side effects of TPE are possible transmission of undiagnosed infectious diseases and immunologic reaction to the foreign plasma 13 …”