Clinical and Clinicopathologic Effects of Plateletpheresis on Healthy Donor Dogs
Plateletpheresis allows highly efficient collection of large numbers of platelets from donor dogs that can be used for the treatment of life-threatening bleeding due to severe thrombocytopenia or thrombopathia. The advantages of a platelet concentrate prepared by apheresis in comparison to the standard platelet-rich plasma/platelet concentrate prepared from a unit of fresh whole blood are greater platelet yield (3 to 4.5 × 1011 vs 1 × 1011) and negligible red blood cell contamination. The purpose of this study was to determine if plateletpheresis using the COBE Spectra is a safe, feasible, and efficacious method for collecting platelets from dogs weighing ~ 20 kg and to document the clinical and clinicopathologic effects of plateletpheresis.
Plateletpheresis was performed on 14 adult healthy mixed breed dogs weighing 18 to 27.7 kg (mean 22.8 kg). Approximate target values for the collections were total platelet yield 3 × 1011, collect volume 220 mL, and run time of 90-110 minutes. CBCs were obtained from donors at baseline, 2 hours post-apheresis, and daily for 1 week. Blood was collected at baseline and every 15 minutes during plateletpheresis for assessment of electrolytes and acid-base status (NOVA CCX) and serum citrate concentration. Dogs were monitored by continuous ECG and indirect blood pressure measurement every 5 minutes. All dogs received 10% calcium gluconate as a constant rate infusion (CRI), with rate adjusted as needed based on serial measurements of [Ca2+].
A high quality platelet product was safely collected from all 14 dogs, with total yields ranging from 2.7 to 4.6 × 1011 platelets in a plasma volume of 220 to 270 mL. Mean donor platelet count was decreased by > 50% 2 hours post-apheresis but returned to baseline level by day 6. There was no difference between mean HCT pre- and post-apheresis. The procedure was generally well tolerated, with no evidence of hypotension. Serum citrate concentrations progressively increased, causing blood [Ca2+] to decrease to < 1 mmol/L in 10 dogs despite calcium supplementation. Lip licking was noted in 3 dogs, and generalized tremors and ventricular ectopy were noted in 1 dog. Two hours following apheresis and discontinuation of calcium CRI, blood [Ca2+] had returned to baseline levels, although [Mg2+] and serum citrate concentrations remained below and above baseline levels, respectively.
The COBE Spectra may be safely utilized for plateletpheresis in dogs weighing approximately 20 kg. Due to the large amount of citrate infused to the donor, calcium supplementation with serial monitoring of blood [Ca2+] is recommended to limit clinical signs of hypocalcemia during the procedure.