I often get asked what the difference is between full code and DNR. So I'm going to take a moment to define these two terms.
Full Code: You do everything possible and necessary to save the life of the person. This means if the patient stops breathing you'll intubate and put the patient on a ventilator, and if his heart stops you'll do chest compressions with ventilations. You will also provide medications necessary to try to save that person. Any patient who does not have a DNR order is considered full code. If you don't know if the patient is a DNR, then you consider the person a full code.
DNR: This stands for do not resuscitate. This means if the patient's heart and breathing stops you do not perform any heroic efforts. You do not intubate or ventilate. However, you will still care for the patient and do whatever is necessary to help the patient get better. The only things you don't do is heroic activity.