The red cell storage lesion(s): of dogs and men

Abstract

The advent of preservative solutions permitted refrigerated storage of red blood cells. However, the convenience of having red blood cell inventories was accompanied by a disadvantage. Red cells undergo numerous physical and metabolic changes during cold storage, the "storage lesion(s)". Whereas controlled clinical trials have not confirmed the clinical importance of such changes, ethical and operational issues have prevented careful study of the oldest stored red blood cells. Suggestions of toxicity from meta-analyses motivated us to develop pre-clinical canine models to compare the freshest vs the oldest red blood cells. Our model of canine pneumonia with red blood cell transfusion indicated that the oldest red blood cells increased mortality, that the severity of pneumonia is important, but that the dose of transfused red blood cells is not. Washing the oldest red blood cells reduces mortality by removing senescent cells and remnants, whereas washing fresher cells increases mortality by damaging the red blood cell membrane. An opposite effect was found in a model of haemorrhagic shock with reperfusion injury. Physiological studies indicate that release of iron from old cells is a primary mechanism of toxicity during infection, whereas scavenging of cell-free haemoglobin may be beneficial during reperfusion injury. Intravenous iron appears to have toxicity equivalent to old red blood cells in the pneumonia model, suggesting that intravenous iron and old red blood cells should be administered with caution to infected patients.

Figure 1

Mortality. The size of the data markers is proportional to the inverse variance of each point estimate.

Figure 2

Survival curves. (A) Kaplan-Meier plot over the 96 hours of study comparing animals challenged with intrapulmonary S. aureus and exchange transfused with 42-day-old (solid circle, solid line) or 7-day-old (open circle, dashed line) stored blood. (B) Serial measures of lung injury. Arterial-alveolar oxygen gradient shows lung damage was significantly worse (higher) in the animals with pneumonia receiving 42-day-old (solid circle, solid line) vs 7-day-old (open circle, dashed line) stored blood at 24 hours (p=0.005) and 48 hours (p=0.01) after bacterial challenge.