Find Us Center for Aero-Digestive Disorders (CADD)Find Us 333 Longwood Avenue, 3rd floor The Center for Aero-Digestive Disorders (CADD) is located on the third floor of 333 Longwood Avenue, across the street from the main hospital. Exit the Patient and Family Garage onto Longwood Avenue and take a right. 333 Longwood is the second building on your right. Copyright © 2008 Children's Hospital Boston