Emergence and early cognitive function in the elderly after xenon or desflurane anaesthesia: a double-blinded randomized controlled trial

Background. Postoperative cognitive impairment after general anaesthesia, especially in the elderly, is a well-recognized problem. Xenon, known to be an N-methyl-D-aspartate antagonist, may be advantageous. In this study, the early cognitive function in the elderly after general anaesthesia with xenon was compared with that after desflurane. Methods. After approval by the local ethical committee and after obtaining written informed consent, patients were enrolled in this randomized, double-blinded, controlled study. Thirty-eight patients (65-75 yr old, ASA status I-III) undergoing an elective surgery with a planned duration of 60-180 min were allocated to either the xenon (n=18) or the desflurane (n=20) anaesthesia group. The primary outcome was the cognitive Test for Attentional Performance (TAP) with its subtests Alertness, Divided Attention, and Working Memory. After baseline assessment 12-24 h before operation, patients were followed-up 6-12 and 66-72 h after operation. Secondary outcomes were emergence times from anaesthesia and the modified Aldrete score. Results. No difference was found between the groups in the TAP at 6-12 and 66-72 h after operation. In the xenon group, emergence time was significantly faster for the following parameters: time to open eyes (P=0.001), to react on demand (P=0.001), to extubation (P=0.001), and for time and spatial orientation (P=0.007). The modified Aldrete score was significantly higher after 30, 45 and 60 min in the xenon group. Conclusions. There was no difference in the postoperative cognitive testing at 6-12 and 66-72 h. Xenon was associated in the elderly with a faster emergence from general anaesthesia than desflurane.