Having undiagnosed Celiac disease, I'd had a myriad of medical issues throughout life that caused a number of very serious and life-threatening emergency surgeries.   

On one of those occasions, I was losing consciousness due to blood loss in the ambulance and have intermittent memory of being wheeled into the ER and voices. Then nothing until floating near the ceiling just below the lights and looking down at the nurse who'd been left alone with instructions to start IV blood transfusion. 

I saw her clearly frantically trying veins in my neck and feet and being unable to find one that wasn't collapsed. I heard either her voice or her panicked thoughts say that she was losing me. 

I was calm and trying to communicate to comfort her in her distress.  At the same time, I asked if I could have five more years because my grandmother and son were dependent on me. 

I was aware of being instantly returned to the body on the table, but then I remained unconscious until a day or so later when awakening from the anesthesia and surgery. 

I was blessed to be undisturbed and calm regarding the experience, with just a sense of awe. There really are not words.