Index of consciousness monitoring during general anesthesia may effectively enhance rehabilitation in elderly patients undergoing laparoscopic urological surgery: a randomized controlled clinical trial

Abstract Background Elderly patients are at a significantly higher risk of perioperative complications. Based on electroencephalogram (EEG) analysis, index of consciousness (IoC) monitoring is a new technique for monitoring anesthesia depth. IoC is divided into two parts: IoC 1 (depth of sedation) and IoC 2 (depth of analgesia). There have only been a few studies in which IoC 1 and IoC 2 are simultaneously monitored to speed up postoperative recovery. We investigated whether combined monitoring of IoC 1 and IoC 2 can effectively improve postoperative recovery in elderly patients undergoing laparoscopic urological surgery under general anesthesia. Methods A prospective, randomized, controlled, double-blind trial was carried out on elderly patients scheduled for laparoscopic urological surgery under total intravenous anesthesia. Patients were assigned to either the IoC group (n = 60) or control group (n = 60) at random. The prevalence of postoperative cognitive dysfunction (POCD) was the primary endpoint. Inflammatory markers, arterial blood gas analysis, postoperative complications, and length of hospital stay were among the secondary endpoints. Results The study included 120 patients with an average age of 71.20 ± 5.06 years. Compared to the control group, the incidence of POCD was significantly lower (19(31.7%) vs. 6(10%); P = 0.003), and serum C-reactive protein(CRP) and glial fibrillary acidic protein(GFAP) concentrations were lower at the end of surgery (CRP: 5.36 ± 3.36 vs. 3.11 ± 2.62; P = 0.000, GFAP: 3.29 ± 1.22 vs. 2.42 ± 1.38; P = 0.000) and 24h after surgery (CRP:11.75 ± 7.52 vs. 8.15 ± 5.24; P = 0.003, GFAP: 4.84 ± 1.20 vs. 3.96 ± 2.23; P = 0.008) in the IoC group. Blood glucose levels at the end of surgery (9.17 ± 2.04 vs. 7.11 ± 1.35; P = 0.000) and the total rate of complications at 7 days after surgery (16(26.7%) vs. 7(11.7%), P = 0.037) were significantly lower in the IoC group. Conclusion IoC monitoring for managing elderly surgical patients can hasten postoperative recovery by reducing intraoperative stress and the resulting systemic and neuroinflammation. TRIAL REGISTRATION: Chinese Clinical Trial Registry Identifier: ChiCTR1900025241（17/08/2019）.