CNSE's First-Ever Blood Drive More than 70 people participated in CNSE's first-ever blood drive in partnership with the American Red Cross on August 31. Every two seconds, someone in the United States needs blood. Nearly 14 million units of red blood cells are used annually for blood transfusions. On any given day, about 38,000 units of red blood cells are needed to treat accident victims, children and adults undergoing surgery, and patients receiving treatment for cancer and other diseases.