Light anesthesia reduces risk of postoperative delirium in major surgery: Study

Australia: Light anesthesia reduces the risk of postoperative cognitive impairment and delirium among patients undergoing major surgery, a recent study has found. The study is published in the British Journal of Anaesthesia. 

Postoperative delirium (POD), a serious complication of surgery, is associated with long-term cognitive decline, prolonged hospitalization, and mortality. Lisbeth A. Evered, Department of Critical Care Medicine, University of Melbourne, Melbourne, VIC, Australia, and the team aimed to determine whether targeting bispectral index (BIS) readings of 50 (light anesthesia) was associated with a lower incidence of POD than targeting BIS readings of 35 (deep anesthesia) in a multicentre randomized clinical trial. 

The trial included 655 at-risk patients undergoing major surgery from eight centers in three countries. Delirium was assessed for 5 days postoperatively using the 3 min confusion assessment method (3D-CAM) or CAM-ICU. They also assessed cognitive screening using the Mini-Mental State Examination at baseline and discharge and the Abbreviated Mental Test score (AMTS) at 30 days and 1 yr.

 The primary outcome was the presence of postoperative delirium on any of the first 5 postoperative days.