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.
ASJC Scopus subject areas
- Cell Biology