LAUSR

In this month’s edition, Joosten et al. evaluated the performance of multiple closed loop systems for administration of anesthesia in 90 patients undergoing major noncardiac surgery in a single center. Anesthesia (hypnosis and analgesia), fluid administration, and ventilation were controlled by separate and independently working closed loop systems; the automated system outperformed manual control and had a significant, albeit minimal, beneficial impact on neurocognitive recovery after surgery. In general, closed loop anesthesia control outperforms manual control: anesthesia, sedation, fluid management, or ventilation all benefit from the use of automated systems. More recently, several of these closed loop systems have been investigated at the same time, with the study by Joosten et al. being the first determining the superior performance of closed loop systems for all three components mentioned before. A common theme of all these studies is that automated systems can keep a given target more closely than manual control, and this is not so much due to the specific form of algorithms or artificial intelligence used but simply due to automated systems more often changing the medication rate per unit of time. As Joosten et al. show again, changes of propofol/remifentanil infusions, fluid administration rates, or ventilation settings are much less frequently performed when humans control them. The primary endpoint of this small study was the determination of cognitive function with automated versus manual control. There was significantly better cognitive function 1 week after surgery when closed loop control was used. With secondary analysis, the percentage of time of Bispectral Index lower than 40 was significantly correlated with a decrease in cognitive function, whereas end-tidal carbon dioxide less than 32 mmHg or mean arterial pressure less than 60 mmHg was not. Independent from automated control, avoidance of low Bispectral Index values during surgery is an important message of this study, following the trend of recent findings. The wider question of this study seems to be the following: When will robotic anesthesia become a daily reality? Robotic anesthesia, defined as anesthesia delivered by an automated control system, will soon be available. It is my opinion that closed loop devices will become available in the United States before target-controlled systems will be Food and Drug Administration–approved. I have used target-controlled system devices all my professional life, starting in the early 1990s; however, there are some important pitfalls. These devices appear like computer-driven anesthesia machines, but in fact running a target-controlled systems propofol pump without quantitative depth of anesthesia monitoring is challenging. Everyone who has used these devices over many years will have also noticed that their pharmacokinetic profile is slightly outdated by our modern patient population, who behave differently from the study population used to define the initial target-controlled systems algorithms. One of the changes our profession has gone through is an ever-increasing demand to multitask, be it by running more than one operating room, or by simultaneously performing administrative or teaching tasks. In addition, the number of parameters to monitor has also increased. It is therefore not surprising that one of the common denominators of studies comparing closed loop control versus manual control is the finding that humans change a given target infusion rate far less frequently than closed loop devices do. I have no doubt that the practice of running more than one operating room, common in the United States but less so elsewhere, will soon be an international standard. Closed loop devices will allow us to maintain a high standard of quality independent from the amount of physical presence. “When will robotic anesthesia become a daily reality?”