What Problems Could Arise From Having Blood In A Person's

What problems could arise from having blood in a person's lungs? Patient has had a some amount of smoke inhalation a five years ago and now she has pacemaker in place. She has had a lot of problems breathing lately and is on oxygen now and she seems to get pneumonia very easily now since the smoke inhalation happened those years ago. But now apparently she has blood in her left lung which from x-rays earlier they thought it was pneumonia again and put a lot of antibiotics intravenously. So what problems could she be facing with the blood in her lung and what might have caused that to take place in your best opinion please?