EEG alpha power and delirium in the postanaesthesia care unit in older adults: the AlphaMax trial part 2 - effect of propofol infusion during emergence from desflurane anaesthesia☆.

BACKGROUND

This arm of the AlphaMax randomised trial evaluated the effect of a short propofol infusion at the end of surgery on EEG alpha power during emergence from anaesthesia and delirium in the PACU in older adult patients.

METHODS

Male and female patients, aged ≥60 yr, were randomised to receive either a short infusion of propofol or routine care during emergence from a standardised desflurane and fentanyl anaesthetic. The primary outcome was EEG alpha power during emergence. The key secondary outcome was delirium in the PACU. As an exploratory analysis, variables linked to delayed cognitive recovery (defined by disorganised thinking on the 3-Minute Diagnostic Interview for Confusion Assessment Method) were identified.

RESULTS

We reduced the sample size because of feasibility issues and the study was underpowered for PACU delirium. A total of 200 participants aged 73 (66 - 80) yr were included. Propofol infusion was associated with lower alpha power (-3.06 [sd 4.1] dB vs -1.82 [sd 3.6] dB, P=0.026) and more burst suppression (66% vs 34%, P<0.001) during emergence. The incidence of PACU delirium was 36.7% in the propofol group and 33.3% (P=0.614) in the routine care group. Participants with disorganised thinking had lower preoperative Montreal Cognitive Assessment scores, lower body weight, higher National Surgical Quality Improvement Program scores, lower intraoperative EEG alpha power, more delta inertia during emergence, and longer PACU and hospital stays than those without disorganised thinking.

CONCLUSIONS

Propofol infusion decreased EEG alpha power and increased burst suppression during emergence; however, there was no difference in the incidence of delirium in the PACU.

CLINICAL TRIAL REGISTRATION: ID:12617001354370.