B, Comparison of changes in infusion rate versus target Ce levels for a continuous 1-hour propofol infusion. In this simulation, there were 4 changes in drug administration. For the TIVA (pink line), there were (1) a 1-mg/kg bolus followed by an infusion of 100 mcg/kg/min, (2) a change in the infusion rate to 150 mcg/kg/min, (3) a change in the infusion rate to 50 mcg/kg/min, and (4) the infusion was turned off. For the TCI (blue line), there were (1) a change from a target Ce of 0 to 2.3 mcg/mL, (2) a change from 2.3 to 3.4 mcg/mL, (3) a change from 3.4 to 1.6 mcg/mL, and (4) a change from 1.6 to 0 mcg/mL. The target Ce levels were selected to be similar to the concentrations achieved with the continuous infusion rates after 20 minutes. This figure illustrates a key advantage of administering propofol via TCI. TCI can achieve and maintain a target concentration faster than a change in a continuous infusion. This advantage for propofol is more evident when increasing versus decreasing the infusion rates. All simulations assumed a 50-year-old, 165-cm, 70-kg female for a 2-hour anesthetic. Simulations were based on published pharmacokinetic and pharmacodynamic models.3,5,12, 13, and 14 Both techniques yield very similar effects, yet TCI achieves and maintains target concentrations more effectively. Source: Considerations for the Maintenance of Anesthesia, Clinical Pharmacology for Anesthesiology Citation: Johnson KB. Clinical Pharmacology for Anesthesiology; 2015 Available at: https://accessanesthesiology.mhmedical.com/DownloadImage.aspx?image=/data/books/1181/joh_ch29_f004a.png&sec=65653590&BookID=1181&ChapterSecID=65653571&imagename= Accessed: October 20, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved