The Prevention of Delirium and Complications Associated With Surgical Treatments Multi Center Clinical Trial

Delirium is a medical term or condition that includes a temporary inability to focus attention and to think clearly. Delirium occurs commonly (10% to 70%) in patients older than 60 undergoing large surgeries. The purpose of this study is to test rigorously whether a drug called ketamine can decrease the chance that patients will experience delirium after their surgery. The investigators are also testing whether ketamine decreases postoperative pain, postoperative opioid consumption, postoperative nausea and vomiting, ICU and hospital length of stay, and adverse outcomes (e.g. hallucinations and nightmares).