Hands Free Anesthesia: Target Controlled Infusion Systems

The target of every form of drug delivery is achieving and maintaining a therapeutic time course of drug effect, while avoiding adverse effects. Intravenous (IV) drugs are usually given using standard dosing guidelines either as a bolus dose or by continuous infusion. Bolus doses are typically administered with a handheld syringe and infusions with an infusion pump. The only patient covariate that is incorporated into a dose calculation is the body weight, while other parameters like age, sex, creatinine clearance etc are often ignored because of the complex mathematical relationship of these covariates while dosing. Target-controlled infusion (TCI) is a technique of infusing IV drugs to achieve a user-defined, predicted (target) drug concentration in a specific body compartment or tissue of interest. TCI systems can rapidly titrate response as necessary, can easily alter depth of anaesthesia and also maintain steady concentrations when required. The potential benefit to clinicians is the more precise titration of anesthetic drug effect. TCI systems can also be instructed to overshoot the desired concentration in the plasma to accelerate the rate of onset of drug effect.