Limitations of Hb/Hct Triggers
Over-reliance on the Hb/Hct triggers for transfusion decision making has been called into question. Use of Hb/Hct alone may overstate anemia, potentially leading to unnecessary transfusion since the volemic status of the patient is unknown. Specifically, intra-operative Hb/Hct measurements are subject to the following limitations:
Hb/Hct is confounded by intravascular hemodilution due to crystalloid/colloid infusion, blood transfusion, insensible losses, third spacing, or acute hemorrhage.
In the early hours after a bleeding event, the Hb/Hct is only a reflection of the resuscitation effort and not the true reduction in red cells [7-9]
Hb/Hct measurments are often delayed or highly unreliable in the dynamic surgical setting.