A doctor tells the story of a little girl

I came to the hospital in critical condition, a little girl needs
To blood transfusion, rare blood type is only available to her sister twins,
I looked at her and gently told her that her sister was between life and death and needed
To her blood to live and reassured her that the injection will not be much sore, and she remained silent
For a moment then she handed over to her parents and went with me to the blood transfusion room.
And not long after we passed the blood to her sister, she came to the girl
She asked me innocently: "Your doctor left me time to die" !!?
Oh God, I thought the blood transfusion would lose her life and yet she did not
Feel free to give it to her sister !!!