Patients with polycythemia associated with cyanotic heart disease may develop a coagulopathy following surgical correction of the heart defect. Milam et al used pre-operative hemodilution in these patients to reduce the frequency and severity of these bleeding complications. The authors are from St. Luke's Episcopal Hospital, Texas Heart Institute and Texas Children's Hospital in Houston.


Patient selection: Patients undergoing cardiopulmonary bypass for cyanotic congenital heart disease


Patients with polycythemia and cyanotic heart disease have evidence of a consumptive coagulopathy with changes including prolonged PT and aPTT, low fibrinogen, elevated fibrin degradation products, increased fibrinolysis, thrombocytopenia, and platelet dysfunction.


Goal: intraoperative hemodilution to a lower hematocrit


Data requirements:

(1) body weight in kilograms

(2) preoperative hematocrit

(3) intraoperative target hematocrit



(1) Estimate the patient's blood volume based on body weight.

(2) Estimate the blood volume required to lower the hematocrit to the desired hematocrit (28% in the example).

(3) Determine the prime volume of crystalloid solution required.


estimated blood volume in mL =

= (body weight in kilograms) * (weight factor)

Body Weight in Kilograms

Weight Factor

< 10

80 mL/kg

10 - 20

75 mL/kg

> 20

70 mL/kg



• These values are some of the standard factors used for estimated blood volume in infants, children and adults based on weights. Other approaches can be used including using different factors for men and women. See Chapter 2.


hemodiluted blood volume required in mL =

= (current hematocrit) / (desired hematocrit) * (estimated blood volume in mL)


prime volume of crystalloid in mL =

= (hemodiluted blood volume) - (estimated blood volume)


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