Answer Happy

Ed Rivers, a third year medical student, was working in the
hospital emergency
department (ED) one night. It was unusually busy in the ED, so the
residents were occupied
with the most severe cases. A patient, Ms. M.B. was brought in
showing signs of dehydration.
Ed tried to give her water, but she vomited. Feeling that he must
try something else and not
wanting to disrupt the residents, he administered 1 L of sterile
distilled water intravenously
(IV).
The questions that follow are aimed at determining the consequences
of Ed’s action.
Assume for simplicity that red blood cells (RBC) contain only
solutes to which the RBC
membrane is impermeable. The osmolarity of the ICF of the RBC and
the ECF is 300 mOsm/L
1) The volume of Ms. M.B.’s plasma was 3 L before Ed
administered the IV. Assume that
there was complete mixing of the administered water with her plasma
but no mixing
with her interstitial fluid. Calculate Ms. M.B.’s plasma osmolarity
after the infusion
mixed with her plasma but before any water entered her RBC.