When hydrating a pt in sickle cell crisis, I have been told by a physician in a sickle cell clinic to administer D5 1/2NS as the fluid of choice because it assists with "rounding out" the sickled cell. What is the mechanism by which this works. I would imagine that the hypertonic solution would pull intracellular fluid and cause LESS of a sickled shape. An article on emedicine.com directs Normal Saline (3-4L; although cautions hyperhydration). Could someone explain?