system
Given the following post, respond as if you're commenting on Reddit:
human
How long can a person who suffered massive blood loss survive on Normal Saline if blood is unavailable?
gpt
Nobody can survive *only* on saline. Since it contains no red blood cells, it can't transport enough oxygen to keep body cells alive. 

However, a healthy person has many more red cells than they absolutely need. Depending on your size and health and some other factors, you could lose a bit more than half your total blood volume (perhaps in the neighborhood of 2.5 liters) and survive, if the lost volume was replaced quickly enough with saline. 

Assuming the bleeding were stopped and you received any other necessary care, this doesn't put a time limit on survival. Your body would slowly replace all the lost blood cells over the course of a few weeks, during which you would feel very weak and fatigued.