Cell-free hemoglobin – the oxygen-carrying molecule normally found inside red blood cells – can be detected in the plasma of critically ill patients with sepsis, and higher concentrations are associated with a higher risk of death, Vanderbilt researchers report in the March issue of Critical Care Medicine. The observational study of 391 patients with sepsis also found that acetaminophen, which inhibits the oxidative potential of hemoproteins, was associated with a lower risk of death and with reduced evidence of oxidative stress.
David Janz, M.D., clinical fellow in Medicine, and colleagues measured plasma levels of cell-free hemoglobin and F2-isoprostanes – markers of oxidative stress – and evaluated acetaminophen exposure from clinical records. They found that patients with higher cell-free hemoglobin were more likely to die in the hospital and that acetaminophen had a protective effect against death.
The findings suggest that cell-free hemoglobin may be an important mediator of oxidative injury in clinical sepsis and that acetaminophen might prevent this injury, providing a foundation for future prospective studies.
This research was supported in part by the Vanderbilt CTSA grant from the National Institutes of Health (RR024975), by other NIH grants (HL103836, HL090785, GM042056, and by awards from the American Heart Association. (Leigh MacMillan/Vanderbilt University)