Effects of electroencephalography and regional cerebral oxygen saturation monitoring on perioperative neurocognitive disorders: a systematic review and meta-analysis

BACKGROUND: Perioperative neurocognitive disorders (PND) is a common postoperative complication including postoperative delirium (POD), postoperative cognitive decline (POCD) or delayed neurocognitive recovery. It is still controversial whether the use of intraoperative cerebral function monitoring can decrease the incidence of PND. The purpose of this study was to evaluate the effects of different cerebral function monitoring (electroencephalography (EEG) and regional cerebral oxygen saturation (rSO(2)) monitoring) on PND based on the data from randomized controlled trials (RCTs). METHODS: The electronic databases of Ovid MEDLINE, PubMed, EMBASE, Cochrane Library database were systematically searched using the indicated keywords from their inception to April 2020. The odds ratio (OR) or mean difference (MD) with 95% confidence interval (CI) were employed to analyze the data. Heterogeneity across analyzed studies was assessed with chi-square test and I(2) test. RESULTS: Twenty two RCTs with 6356 patients were included in the final analysis. Data from 12 studies including 4976 patients were analyzed to assess the association between the EEG-guided anesthesia and PND. The results showed that EEG-guided anesthesia could reduce the incidence of POD in patients undergoing non-cardiac surgery (OR: 0.73; 95% CI: 0.57–0.95; P = 0.02), but had no effect on patients undergoing cardiac surgery (OR: 0.44; 95% CI: 0.05–3.54; P = 0.44). The use of intraoperative EEG monitoring reduced the incidence of POCD up to 3 months after the surgery (OR: 0.69; 95% CI: 0.49–0.96; P = 0.03), but the incidence of early POCD remained unaffected (OR: 0.61; 95% CI: 0.35–1.07; P = 0.09). The remaining 10 studies compared the effect of rSO(2) monitoring to routine care in a total of 1380 participants on the incidence of PND. The results indicated that intraoperative monitoring of rSO(2) could reduce the incidence of POCD (OR 0.53, 95% CI 0.39–0.73; P < 0.0001), whereas no significant difference was found regarding the incidence of POD (OR: 0.74; 95% CI: 0.48–1.14; P = 0.17). CONCLUSIONS: The findings in the present study indicated that intraoperative use of EEG or/and rSO(2) monitor could decrease the risk of PND. TRIAL REGISTRATION: PROSPREO registration number: CRD42019130512.