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Man vs Machine: Closed Loop or Manual Intravenous Anesthesia?

Nathan, Naveen MD

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doi: 10.1213/ANE.0000000000005731

Postoperative cognitive dysfunction (POCD) is an unfortunate reality for many patients after surgery and is multifactorial in etiology. The total anesthetic burden endured during the surgical procedure is clearly one variable that may impact the incidence and severity of POCD. Authors in this issue of Anesthesia & Analgesia asked whether the titration of intravenous anesthetics through closed-loop infusion might lower the total anesthetic delivered and offer the benefit of decreased POCD. Over 200 patients were randomized to either manual adjustment of propofol and remifentanil infusions versus closed-loop titrations for noncardiac surgery. As this infographic shows, no difference in POCD was found between the 2 groups. This finding could be explained by multiple factors such as the power to detect POCD given the sample size, the tools used to define POCD, and the fact that remifentanil decreases the required amount of anesthetic in general. A multitude of other factors could also have influenced these results and are addressed in their discussion. Interestingly, the total amount of propofol used was lower for patients on closed-loop infusions versus manual administration. Further studies are required to further explore the utility of closed-loop infusions and outcomes.


    1. Mahr N, Bouhake Y, Chopard G, et al. Postoperative neurocognitive disorders after closed-loop versus manual target controlled-infusion of propofol and remifentanil in patients undergoing elective major noncardiac surgery: the randomized controlled POCD-ELA trial. Anesth Analg. 2021;133:837–847.
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