Optimization Methods to Minimize Emergence Time While Maintaining Adequate Post-Operative Analgesia

Utah State University

A rapid emergence from anesthesia combined with an extended duration of adequate analgesia is desired. Difficulties arise when trying to achieve a rapid emergence and provide adequate analgesia for procedures associated with moderate post operative pain. We propose to use pharmacokinetic (PK) and pharmacodynamic (PD) models with optimization techniques to determine anesthetic drugs ratios to improve post-anesthetic outcomes of emergence and analgesia. We hypothesize that optimized propofol, remifentanil, and fentanyl administrations will shorten emergence time and extend the period of adequate analgesia during patient recovery. Anesthesiologists administered a general anesthetic to 21 patients for laparoscopic procedures with propofol, remifentanil, and fentanyl according to their standard practice. The theoretical improvement provided by the optimization was measured by comparing the time differences between the control predictions and the optimized prediction of the TROR time and TRON time. In the control group the TROR was 10.2+-5.8 minutes (mean +- SD) and TRON was 3.5+-5.0 minutes after emergence. In the optimized group the TROR was 7.5+-2.2 minutes or 26% faster (p < .001, paired t-test) and the TRON was 7.4 +-2.4 minutes or 88% longer (p < .00001, t-test). Optimized administrations of propofol, remifentanil, and fentanyl resulted in a theoretically shorter emergence time and a longer period of adequate postoperative analgesia. The optimization algorithm shows potential for real-time clinical guidance in drug management.