The older the patient is, the longer the swelling after surgery may be due to the large amount of fluids given after the surgery. Due to the cardiac and renal insufficiency of the elderly, a large amount of water cannot be metabolized efficiently, which makes it easy for the swelling to occur. 1. Cardiac and renal insufficiency: due to the older, the body function will also decline, heart function and kidney function will decline, drainage function will also decline, easy to appear oliguria, serious cases will even appear no urine, water can not be discharged, a large number of stagnation, which will lead to prolonged swelling, but also does not exclude other pathological factors lead to swelling, such as blood and other cardiovascular diseases. 2. Massive infusion: after massive infusion, the body is unable to carry out compensatory discharge, resulting in massive fluid retention and post-surgical swelling. For prolonged swelling after surgery, it is necessary to consult a doctor in time, make a clear diagnosis under the guidance of the doctor and treat it actively.