Early cognitive function in elderly patients after laser laryngeal surgery: des vs prop

Postoperative cognitive impairment is one of the most common complications in elderly surgical patients. Laser laryngeal surgery is a short procedure, but characterized by high risk of disastrous airway fire. So the recommended oxygen concentration is less than 30%. For elderly patients, because of preoperatively declined cardiovascular and lung function and cognitive function, there is a potential that intraoperative low oxygen concentration may lead to drop of arterial oxygen tension, decrease of brain oxygenation, and exacerbate brain function impairment. Intravenous anesthesia and inhalation anesthesia is two commonly used technique for general anesthesia. Consequently, we carry out this study to identify whether different classes of anesthetics can affect postoperative cognitive function in old patient undergoing laser laryngeal surgery.