Blood Transfusions Correct Anemia and Improve Tissue Oxygenation in Surgical and Critically ill Patients.

Anemia is a wide spread condition world-wide associated with increased loss of quality of life, organ failure and mortality. Its causes are multifactorial including iron deficiency, heart and renal failure, COPD, malignancies, various infectious and inflammatory diseases, and blood loss such as occurs in trauma and GI bleeding. The underlying reason why anemia is considered to be life threatening and responsible for organ injury and loss of quality of life is due to the limitation in oxygen delivery to the tissues caused by a reduction in the number of oxygen carrying red blood cells. Anemia can result in shortness of breath, renal and cerebral dysfunction, increased cardiac stress, reduced exercise capacity and physiological reserve. If not corrected adequately it can result in organ failure and even in mortality. The World Health Organization for defining anemia is Hb levels being lower than 13 g/dL for men and 12 g/dL for women. Under such a definition it must be considered that a significant portion of hospitalized patients are anemic either pre-existing or being caused by standard clinical procedures. Often unrecognized in-hospital anemia can be a main contributor organ dysfunction in surgical and intensive care patients (1). Such iatrogenic anemia can be caused by hemodilution due to the routine administration of non-oxygen carrying crystalloids solutions, often in large amounts resulting in a reduced number of circulating oxygen carrying red blood cells.