Comparison of 4 blood storage methods in a protocol for equine pre-operative autologous donation

Objective - To compare viability of equine whole blood stored by 4 different methods, and to establish optimal storage protocols for an equine autologous blood donation program. Study Design - In vitro study of stored equine whole blood. Animals - Six healthy adult horses. Methods - Blood from each horse was collected into 4 different containers: glass bottles containing acid-citrate-dextrose solution (ACD), plastic bags containing ACD, citrate-phosphate-dextrose (CPD), and CPD with supplemental adenine (CPDA-1). Blood was stored for 5 weeks and sampled at 2-day intervals. Standard hematologic and biochemical variables were evaluated, and adenosine-5- triphosphate (ATP) and 2,3-diphosphoglycerate (2,3-DPG) concentrations were measured and normalized to total hemoglobin content. Results - Plasma hemoglobin, % hemolysis, lactate, potassium, ammonia, and lactate dehydrogenase (LDH) increased, whereas glucose concentration and pH decreased in all stored blood over 5 weeks. There was a temporal increase in hemolysis with all storage methods, but the increase was greatest in glass bottles. Lactate and ammonia were highest in CPD and CPDA-1 samples, indicating more active red blood cell (RBC) metabolism. 2,3-DPG concentrations decreased during storage, but were optimally preserved with CPDA-1. ATP concentrations were significantly higher for blood stored in CPDA-1, and were lowest in glass bottles. Conclusions - Hematologic and biochemical values measured for blood stored in CPDA-1 are suggestive of improved RBC viability compared with other storage methods. With the exception of ATP, results from stored equine blood were similar to those reported for other species. Clinical Relevance - Commercial CPDA-1 bags appear to be the optimal storage method for equine whole blood.