Patient selection: Eisenmenger syndrome and erythrocytosis (hematocrit > 55%)
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Clinical Situation
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Management
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dehydration secondary to poor oral intake, diarrhea, diuresis, burn, fever and/or diaphoresis
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rehydrate
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non-cardiac surgery
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isovolumic phlebotomy before surgery and prevention of any hypovolemia
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symptoms of hyperviscosity and microcytic indices (low MCV) associated with iron deficiency
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correction of iron deficiency, with close monitoring for sudden worsening of hyperviscosity symptoms, which may require isovolumic phlebotomy
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symptoms of hyperviscosity and normocytic indices (normal MCV)
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isovolumic phlebotomy
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where:
• Isovolumic phlebotomy = removal of a unit/pint of whole blood (500 mL) with replacement of an equal volume of normal saline, fresh frozen plasma, salt-free albumin or dextran solution.
• The goal of phlebotomy before surgery is to reduce the hematocrit to <= 65%. The goal of phlebotomy for hyperviscosity is to reduce symptoms rather than to achieve a target hematocrit.
• Symptoms of hyperviscosity may include visual disturbances, headache, dizziness, or subtle neurologic abnormalities.
• Microcytic red blood cells are less deformable than larger red blood cells and so are associated with a higher whole blood viscosity.
• Iron replacement in an iron deficient patient may be followed by increased erythropoiesis, resulting in increased hyperviscosity.
• A patient with microcytosis associated with thalassemia would not benefit from the iron replacement unless there was mixed thalassemia and iron deficiency.
