As an ICU nurse in my previous life, transfuse 1 mL of packed red blood cells per 1 mL of blood loss. Give 3 mL IV fluids for every 1 cc blood loss. I've never given whole blood. Always packed red blood cells (PRBC's), fresh frozen plasma (FFP) or platelets.
Usually a transfusion depends on where a patient started with their Hemoglobin and hematocrit. The critical point of transfusing a patient is around a hemoglobin of 7 (normal 12-16) or less, hematocrit of 20 (normal 39-48). It depends too on where the patient started ands on anticipated blood loss as in a trauma or surgery. Some people walk around with an H&H of 7&22.
People with low H&H's are tired, weak, pale and in the incidence of trauma they act hazy and disoriented, just to name a few symptoms. Some people even get short of breath. Blood carries oxygen to the brain s if the brain is low on oxygen, brain cells don't work well. Here in my hospital we are very cautious about giving blood and only do it when absolutely necessary because of the risk factors involved; HIV, Hepatitis, transfusion reactions. Though the blood is thoroughly screened for infectious diseases, you cannot be 100% always.
Anyway, does this help?
~Sheila
