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: Based on electroencephalogram (EEG) analysis, index of consciousness (IoC) monitoring is a new technique for monitoring anesthesia depth. IoC is divided into IoC₁ (depth of sedation) and IoC₂ (depth of analgesia). The potential for concurrent monitoring of IoC₁ and IoC₂ to expedite postoperative convalescence remains to be elucidated. We investigated whether combined monitoring of IoC₁ and IoC₂ can effectively enhances postoperative recovery compared with bispectral index (BIS) in elderly patients undergoing laparoscopic urological surgery under general anesthesia.

Methods: In this prospective, controlled, double-blinded trail, 120 patients aged 65 years or older were arbitrarily assigned to either the IoC group or the control group (BIS monitoring). All patients underwent blood gas analysis at T₁ (before anesthesia induction) and T₂ (the end of operation). The Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were administered to all patients at T₀ (1 day before surgery) and T₄ (7 days after surgery). Serum concentrations of C-reactive protein (CRP) and glial fibrillary acid protein (GFAP) were assessed at T₁, T₂, and T₃ (24 h after surgery). Postoperative complications and the duration of hospitalization were subjected to comparative evaluation.

Results: The incidence of postoperative cognitive dysfunction (POCD) was notably lower in the IoC group (10%) than in the control group (31.7%) (P = 0.003). Postoperative serum CRP and GFAP concentrations exhibited significant differences at time points T₂ (CRP: P = 0.000; GFAP: P = 0.000) and T₃ (CRP: P = 0.003; GFAP: P = 0.008). Postoperative blood glucose levels (P = 0.000) and the overall rate of complications (P = 0.037) were significantly lower in Group IoC than in Group control.

Conclusion: The employment of IoC monitoring for the management of elderly surgical patients can accelerate postoperative convalescence by mitigating intraoperative stress and reducing peripheral and central inflammatory injury.

Trial registration: Chinese Clinical Trial Registry Identifier: ChiCTR1900025241 (17/08/2019).

Keywords: Elderly patients; General anesthesia; Index of consciousness monitoring; Laparoscopic urological surgery; Postoperative outcome.