Bill Barker, MD Bill Barker, MD, is a doctor with AHN Medicine Institute, specializing in pulmonary and critical care. He diagnoses and treats conditions of the lungs, upper airways, cavity, and chest wall and provides personalized care for patients with asthma, COPD, and interstitial lung disease. He went to medical school at Medical College of Ohio in Toledo, Ohio. Dr. Barker did his residency at the Riverside Methodist Hospital in Columbus, Ohio and his fellowship in pulmonary and critical care at University of Virginia Medical Center in Charlottesville, Virginia. He is certified by the American Board of Internal Medicine and is associated with the American College of Chest Physicians and the American Thoracic Society. Dr. Barker believes in taking the time to talk to patients and their families to explain medical conditions in a way that is relatable. He sees patients ages 18 and older.