Could I REALLY die?

This friday I will have surgery to repair a fractured bone in my face. I had arthroscopic knee surgery about 10 years ago and had complications with the anesthetics, and because of that past history the Dr. is telling me there is a risk of death and asking me if I have an "advance directive" or other legal paperwork in place that will give someone decision making power over me. I AM SCARED AS HELL!!!