Postoperative delirium is a serious complication of surgery associated with prolonged hospitalisation, long-term cognitive decline, and mortality. Associate Professor Lisbeth Evered joined us from New York to discuss her recent paper, published in the British Journal of Anaesthesia, with Associate Professor Christine Ball. This important paper resulted from a sub-study of the BALANCED trial to determine whether targeting bispectral index (BIS) readings of 50 (light anaesthesia) was associated with a lower incidence of POD than targeting BIS readings of 35 (deep anaesthesia).