Two-year-old purpose-bred beagles (n = 24) infected with Staphylococcus aureus pneumonia were randomized in a blinded fashion for exchange transfusion with either 7- or 42-day-old canine universal donor blood (80 mL/kg in 4 divided doses). Older blood increased mortality (P = .0005), the arterial alveolar oxygen gradient (24-48 hours after infection; P ≤ .01), systemic and pulmonary pressures during transfusion (4-16 hours) and pulmonary pressures for ~ 10 hours afterward (all P ≤ .02). Further, older blood caused more severe lung damage, evidenced by increased necrosis, hemorrhage, and thrombosis (P = .03) noted at the infection site postmortem. Plasma cell–free hemoglobin and nitric oxide (NO) consumption capability were elevated and haptoglobin levels were decreased with older blood during and for 32 hours after transfusion (all P ≤ .03). The low haptoglobin (r = 0.61; P = .003) and high NO consumption levels at 24 hours (r = ?0.76; P < .0001) were associated with poor survival. Plasma nontransferrin-bound and labile iron were significantly elevated only during transfusion (both P = .03) and not associated with survival (P = NS). These data from canines indicate that older blood after transfusion has a propensity to hemolyze in vivo, releases vasoconstrictive cell-free hemoglobin over days, worsens pulmonary hypertension, gas exchange, and ischemic vascular damage in the infected lung, and thereby increases the risk of death from transfusion.
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机译：将两岁的被感染金黄色葡萄球菌肺炎的专用小猎犬（n = 24）以盲法随机分配，与7或42天的犬通用供体血液（80 mL / kg分成4份）交换输血剂量）。老年血液会增加死亡率（P = .0005），动脉肺泡氧梯度（感染后24-48小时; P≤.01），输血期间的全身和肺部压力（4-16小时）以及之后约10小时的肺部压力（所有P≤.02）。此外，较老的血液对肺部造成了更严重的损害，死后感染部位的坏死，出血和血栓形成增加（P = .03）。在输血期间和输血后32小时，血浆中无细胞的血红蛋白和一氧化氮（NO）的消耗能力提高，触珠蛋白水平降低（所有P≤.03）。触珠蛋白含量低（r = 0.61; P = 0.003）和24小时时高NO摄入水平（r =α0.76; P <.0001）与不良的生存率相关。血浆非转铁蛋白结合的和不稳定的铁仅在输血期间显着升高（均为P = .03），而与生存无关（P = NS）。来自犬类的这些数据表明，输血后的旧血倾向于在体内溶血，在几天内释放无血管收缩的无细胞血红蛋白，加重受感染肺部的肺动脉高压，气体交换和缺血性血管损伤，从而增加死亡风险从输血。
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