Potential biomarkers of tissue hypoxia during acute hemodilutional anemia in cardiac surgery: A prospective study to assess tissue hypoxia as a mechanism of organ injury.

Purpose: Hemodilutional anemia is associated with acute kidney injury (AKI) and mortality in patients undergoing cardiac surgery by mechanisms that may include tissue hypoxia. Our hypothesis was to assess if changes in the potential hypoxic biomarkers, including methemoglobin and erythropoietin, correlated with a decrease in hemoglobin (Hb) concentration following hemodilution on cardiopulmonary bypass (CPB).

Methods: Arterial blood samples were taken from patients (n = 64) undergoing heart surgery and CPB at baseline, during CPB, following CPB, and in the intensive care unit (ICU).