Effects of two different anesthesia-analgesia methods on incidence of postoperative delirium in elderly patients undergoing major thoracic and abdominal surgery: Study rationale and protocol for a multicenter randomized controlled trial

Delirium is a common complication in elderly patients after surgery and associated with increased morbidity and mortality. Studies suggest that deep anesthesia and intense pain are important precipitating factors of postoperative delirium. Neuraxial block is frequently used in combination with general anesthesia for patients undergoing major thoracic and abdominal surgery.