ABSTRACT
Perioperative blood loss in the perioperative period is one of the most common indications of blood transfusion. The blood volume (BV) consists of the plasma volume (PV) and the red cell mass or blood cells. The pathophysiology of the trauma-induced coagulopathy-hypothermia-acidosis triad mandates early institution of damage control resuscitation (DCR). Accurate and timely assessment of intraoperative blood loss is required for judicious replacement with appropriate amounts of crystalloid/colloid or blood and blood products. As the intravascular volume is lost to about 10"-15", compensatory neuroendocrine response causes redistribution of blood from the skin, muscles, and splanchnic circulation to the central compartment, thus preserving flow to the vital organs. Karl Landsteiner in 1901 described the ABO system of blood grouping, and since then almost 346 red cell antigens and 35 blood group systems have been recognized by the International Society of Blood Transfusion (ISBT). Antibody screening is performed routinely on donor blood and frequently performed in the likely recipient.
