- Maintaining an appropriate depth of anesthesia during surgery can be challenging; excessively deep anesthesia can potentially result in intraoperative hemodynamic instability or postoperative delirium/cognitive dysfunction, while inadequate anesthesia can lead to excessive catecholamine stimulation, possible disruptive patient movement, and/or intraoperative recall.
- Numerous studies have investigated the use of closed-loop systems to safely automate the delivery of anesthetic agents and maintain an appropriate depth of anesthesia. These studies often integrate continuous bispectral index (BIS) monitoring with computerized controller algorithms to adjust infusion rates in real time.
- This systematic review and meta-analysis included 17 trials (1898 patients) that compared closed-loop automated systems with standard care, i.e., clinicians manually adjusting anesthetic delivery.
- The primary outcome was the proportion of time that BIS values were maintained with 10 units of a target.
- Automated closed-loop systems outperformed standard care, with time within the targeted BIS range increased by 17.6% in the patients managed via automated closed-loop systems.
- In addition, the amount of time patients spent with a BIS value <40 was significantly reduced while using automated closed-loop systems, whereas time with BIS >60 did not differ between the groups. Time to extubation was also shorter in the closed-loop systems group.
- No differences were noted in propofol consumption or vasopressor use.
- The authors concluded that BIS-guided closed-loop systems with automated hypnotic control achieve a superior safety profile in anesthetic depth control, specifically reducing the incidence of excessively deep anesthesia without increasing light anesthesia.
Summary of "Closed-loop systems for automated hypnotic drug delivery during general anaesthesia: a systematic review and meta-analysis"
Summary published June 15, 2026
