Target-Controlled Infusion Systems

Abstract

Drug delivery by target-controlled infusion (TCI) allows automatic adjustments of the infusion rate of a drug to maintain a desired target concentration. Since drug effect is more closely related to blood concentration than to infusion rate, drug delivery via TCI is capable of creating stable blood concentrations of intravenous anaesthetics and analgesics. In this article the concept and history of TCI are described. The rational administration of TCI requires an appropriate pharmacokinetic data set and knowledge of the concentration-effect relationship; therefore, general pharmacokinetic and pharmacodynamic aspects of intravenous anaesthetics and analgesics are also addressed. Intraoperative investigations have demonstrated that TCI drug delivery allows rapid titration to a desired effect. The use of TCI for postoperative analgesia is still experimental, but TCI can, in part, overcome the disadvantages associated with continuous infusions and patient-controlled analgesia regimens in the postoperative period. Although TCI is capable of creating stable blood concentrations, when the target concentration is changed the resulting effect correlates better with a theoretical effect site concentration. The efficacy of TCI systems that can perform effect-site steering are still to be explored.

A Non-invasive Monitoring of Propofol Concentration in Blood by a Virtual Surface Acoustic Wave Sensor Array

“…It is an intravenous dose method to help control or maintain an adequate depth of anesthesia by adjusting the drug concentration, TCI is widely used in clinical anesthesia monitoring and proved to be effective. 3,4 The targets of the propofol concentration was set according to the anesthesiologist's advice during the operation. Typically, the required propofol concentration for the maintenance of anesthesia was from 1 to 10 μg/ml.…”

“…However, there is no efficient method to continuously monitor the plasma concentration without other side-effects. 2 Target-controlled infusion (TCI), 3,4 as a widely employed method in clinical, is based on an established pharmacokinetic and pharmacodynamics model. Once the target propofol concentration in the blood is set, the required dose of propofol to achieve and maintain the target concentration will be calculated and infused to patients.…”

Comparison of Propofol-Remifentanil and Desflurane-Remifentanil in Target-Controlled Infusion

“…This technique provides a better titration of anesthetic drugs estimated at approximately 30% by considering the individual pharmacokinetic and pharmacodynamic differences of each sequential dose applied. [4,5] This infusion technique converts a predetermined target concentration to the amount of drug to be administered with a syringe infusion pump per unit time. This conversion is performed automatically by a microchip that is programmed by an algorithm that uses a pharmacokinetic model of the drug to be dispensed in the pump.…”