Effects of closed-loop intravenous anesthesia guided by Bispectral Index in adult patients on emergence delirium: a randomized controlled study.

Background: Emergence delirium (ED) is an acute change in cognition after general anesthesia (GA) occurring in operative room, recovery room or in postanesthesia care. The automated propofol-remifentanil titration by Bispectral Index (BIS) (AutoTIVA) avoids period of deep (BIS<40) anesthesia and could potentially decrease the ED. The aim of this study was to evaluate ED in surgical patients under AutoTIVA, manual titration of propofol-remifentanil (ManualTIVA) or volatile BIS-guided GA. Moreover, we aimed to evaluate age-related postoperative Mini-Mental State Examination (MMSE) changes.

Methods: One hundred and thirty-two adult patients scheduled for elective urologic surgery were randomized in: AutoTIVA, desflurane (DES), sevoflurane (SEVO), ManualTIVA anesthesia. The MMSE was performed before GA and 15 minutes after tracheal extubation.

Results: The percentage of BIS 40-60 was significantly higher in the AutoTIVA compared to DES, SEVO and ManualTIVA (87% vs. 78 %, 58%, 39%, respectively; P≤0.001). The percentage of BIS<40 was significantly lower in AutoTIVA than in the other groups (P<0.001). No difference in hemodynamics was found among groups. Postoperative MMSE scores were similar to baseline in the AutoTIVA (26 [24-28] vs. 26 [23-28]) while they markedly decreased in all other groups (P<0.001). Postoperative MMSE decreased at any age. None experienced awareness was recorded.

Conclusions: Our results suggest that patients treated with AutoTIVA performed better in the cognitive test compared to the other groups receiving manual target-controlled GA due to a higher adequate level of anesthesia measured by BIS. Cognitive tests should be performed to test ED in all patients undergoing GA.