Anesthesia Maintenance With Target-controlled Infusion of Propofol and Remifentanil at Fixed Ratio

Overview

The impact of anesthesia depths on early postoperative neurocognitive complications after total intravenous anesthesia (TIVA) remains controversial. In some studies investigating TIVA, anesthesiologists mainly achieve the target depth of anesthesia by adjusting the dose of propofol, whereas the doses of opioids remains comparable between different anesthetic depth groups, possibly resulting inadequate analgesia. This study is aimed to investigate the impact of different anesthesia depths maintained by target-controlled infusion of propofol and remifentanil at a fixed ratio on the incidence of early postoperative neurocognitive complications in older patients undergoing noncardiac surgery.

Early postoperative neurocognitive complications are associated with worse perioperative and long-term outcomes, substantially affecting patients' prognosis and recovery and imposing a significant healthcare and economic burden. Bispectral index (BIS) is an objective and quantitative monitoring parameter used to assess patients' depth of anesthesia. Maintenance of general anesthesia under the guidance of BIS monitoring has been shown to reduce the incidence of early postoperative neurocognitive complications following inhalational anesthesia or combined intravenous-inhalational anesthesia. However, the impact of different depths of anesthesia maintenance on early postoperative neurocognitive complications after total intravenous anesthesia (TIVA) remains controversial. In some studies investigating TIVA, anesthesiologists mainly achieve the target BIS by adjusting the dosage of propofol, whereas the dosage of opioids remains comparable between different anesthetic depth groups. Based on previous studies, the investigators supposed that target-controlled infusion of propofol to remifentanil at a fixed ratio might ensure adequate intraoperative sedation and analgesia and reduce postoperative neurocognitive complications. This study is aimed to investigate the impact of different anesthesia depths by target-controlled infusion of propofol and remifentanil at a fixed effect-site concentration ratio on the incidence of early postoperative neurocognitive complications in older patients undergoing noncardiac surgery.