Apatient experienced great blood loss. in an attempt to quickly replenish body fluids, a volume of distilled water equal to the blood lost was introduced directly into a blood vein. what is the most likely result of this treatment

The result of this treatment will decrease the osmotic pressure of the blood, causing the cell is losing water molecule by osmosis. 
Administering pure water as resuscitation fluid might also lower the concentration of electrolyte in the blood, causing electrolyte imbalance. It is recommended to use normal saline(0.9% NaCl) solution for resuscitation as the solution is having the same osmotic pressure, thus won't inducing osmosis.