• The usual hematocrit for a packed red cell product is 70-80%.
• A rough estimate of total blood volume in children is 80 mL/kg and in adults is 65 mL/kg. Males tend to have a slightly greater blood volume than females. A person at the extremes of body weight would need a more explicit equation (see Chapter 2).
• The equation for automated exchange transfusion is "(hematocrit initial) * (total blood volume)". In the footnote in Wayne et al they refer to hematocrit for packed RBCs as 0.7-0.8. I'm assuming then that (hematocrit in percent) / 100 is appropriate, else the number would be very large.
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