Anesthesia target-controlled pump

Controlled infusion is based on the theory of pharmacokinetics-pharmacodynamics, using computer to simulate the process and function of drugs in vivo, looking for the most reasonable medication scheme, and then controlling the drug injection pump to stabilize the drug concentration in blood or the concentration of effective parts at the expected value, thus controlling the depth of anesthesia, and adjusting the drug delivery system at any time according to clinical needs. Target-controlled infusion can reach the target concentration quickly and smoothly, so the hemodynamics is stable during anesthesia induction, the depth of anesthesia during operation is easy to adjust, and the recovery time of patients can be predicted after stopping the drug after operation. This method is simple, accurate and controllable. Due to the errors of pharmacokinetic model and individual differences of patients, there will be some errors between the target-controlled concentration of patients and the measured blood drug concentration, but in fact, the changes of target-controlled concentration have a good correlation with clinical pharmacodynamic indexes such as blood pressure, heart rate and bispectral index (BIS), so the influence caused by this systematic error can be ignored.

TCI can be divided into: ① target-controlled infusion of plasma: for drugs with small t 1/2 ke0, the plasma concentration should be selected as the target concentration; ② Target-controlled infusion in the effect room: target concentration should be selected for drugs with larger t 1/2 ke0. Taking the concentration of the effect room as the target concentration, it takes effect quickly, but the peak blood concentration may affect hemodynamics.

According to the different target control loops, TCI can be divided into: ① open loop: no feedback device, and the anesthesiologist sets the target concentration according to clinical needs; ② Closed-loop CL-TCI: The drug delivery system is automatically adjusted through feedback signals (such as BP, HR, BIS). CL-TCI is the most ideal target control system, which overcomes the differences in pharmacokinetics and pharmacodynamics of individuals and can provide individualized anesthesia depth. The goal of target control is the patient's response rather than a certain concentration, and the speed of administration is changed according to the individual needs of patients, so as to avoid excessive or insufficient drugs and avoid the deviation of observers.

Open loop is widely used now. When in use, the patient's age, sex, height, weight and other data are input, and the target blood drug concentration is set.