The Effect of Storage on Ammonia Concentration in Canine Packed Red Blood Cells.

Objective: To determine the effect of storage on ammonia concentration in canine packed red blood cell (pRBC) units.
Design: In vitro and in vivo study.
Setting: University Veterinary Teaching Hospital.
Interventions: Ammonia concentration was measured in 7 units of canine pRBC prepared in citrate-phosphate-dextrose (CPD) and Adsol^a on Days 1 and 35 of storage. Ammonia was measured in 4 additional units of canine pRBC on Days 0, 7, 14, 21, 28, and 35. Plasma ammonia was also determined in 5 anemic dogs receiving pRBC.
Measurements and Main Results: Ammonia concentration increased from 73 ± 15 mmol/L (mean ± SD) on Day 1 to 800 ± 275 mmpl/L on Day (p<0.001). When measured every 7 days in 4 units of canine pRBC, ammonia concentration increased from 23 ± 8 mmol/L on Day 0 to 179 ± 13 mmol/L (Day 7), 276 ± 56 mmol/L (Day 14). 383 ± 47 mmol/L (Day21), 466 ± 30 mmol/L (Day 28), and 562 ± 27 mmol/L (Day 35) (p<0.05 for all comparisons). In a preliminary study, plasma ammonia concentration measured in blood samples from 5 anemic dogs without primary liver disease immediately before and after transfusion with 5–10 ml/kg of stored pRBC remained in the normal reference range.
Conclusions: The ammonia concentration in stored canine pRBC increased markedly with time. In this preliminary study, ammonia concentrations in dogs without primary liver disease did not increase above the reference range after transfusion with pRBC.