Q: In a euvolemic patient with sickle cell crisis normal saline is not a fluid of choice for intravenous maintenance. Why?
Answer: In a euvolemic patient with sickle cell crisis the fluid of choice for intravenous fluid maintenance is either quarter-normal or half-normal saline. This is because patients with sickle cell disease cannot excrete sodium effectively, and quickly develop hypernatremia. Serum hypernatremia causes red cell dehydration, resulting in more "sickling" of the cells.
Okpala I. The management of crisis in sickle cell disease. Eur J Haematol. 1998;60:1–6.