I have a recurring nightmare where I am performing CPR on a patient who turns out to be my husband. Last Monday, my nightmare nearly came true. It was 2:50 p.m., and the Massachusetts General Hospital ER was filled to capacity. In the section where I was working, my patients were critically ill, with strokes, heart attacks and overwhelming infections. Even the hallways were packed with patients receiving emergency treatments. A call over the loudspeakers announced that there had been two explosions. Many people were injured. That's all we knew.