Fewer than 2% of patients had pneumonia after surgery. Of these, 21% died within 30 days. Patient characteristics associated with higher risk for pneumonia were age older than 60 years, regular use of steroid drugs (like prednisone), chronic lung disease, history of major stroke, recent alcohol and tobacco use, recent weight loss, requiring more than 4 units of transfused blood before surgery, and impaired physical or mental function. Several types of surgery increased the risk for pneumonia: emergency surgery; general rather than spinal anesthesia; and surgeries that involved the brain, neck, chest, upper abdomen, or arteries in the abdomen or legs. If a person had few or none of these characteristics, only 2 in 1000 patients developed pneumonia. Fifteen percent of persons with several risk factors developed pneumonia.