Reducing the risk of delirium after major surgery.
D000368:Aged; D000369:Aged, 80 and over; D054810:Deep Sedation / Q000009:adverse effects*; D003693:Delirium / Q000139:chemically induced* / Q000517:prevention & control*; D006801:Humans; D009407:Nerve Block; D011183:Postoperative Complications / Q000517:prevention & control*