The Research And Design Of Closed-loop TCI System

TCI is an accurate target controlled infusion to adjust to the concentration of plasma or effect chamber, which is based on pharmacokinetics. Traditional single channel opend-loop TCI system needs anesthesiologist to observe the changes of the physiological characteristic of the patient in the whole operation process, and then adjust to the target concentration of anaesthetics combined with own clinical experience. The defects of this way is that the target concentration of multiple drugs can not be renewed at the same time, thus affect the stability of the anesthetic effect. Besides, this way strongly depends on the doctor and can not monitor the patient’s physical condition in real time, so it is with an amount of risk. Because of this, this paper presents a closed-loop TCI system, which can reduce the dependence of the doctor and increase the stability of the drug.This system consists of one PC, two injection pumps and one Narcotrend monitor in hardware, and is written in Qt C++ in software. First, this system acquires patient’s EEG information during the operation process through serial communication. Then it figures out the new target concentration of propofol and remifentanil using the control algorithm. Finally, it updates the new target concentration to TCI target control software stanpump using the window function and simulate the keystroke events, so that the injection pump makes corresponding adjustment. This system has the following characteristics:1) Using simulated keyboard technology to complete the TCI closed loop control, so it do not need to add additional SCM to control the injection pump, which is with high efficiency and saving resources;2) The system automatically calculates the new target concentration, which can not only reduce the workload of the anesthesia doctor, but also avoid the mistakes caused by manual operation that makes the system more efficient and stable;3) Real-time monitoring the changes of patient’s physiological parameters and timely processing the abnormal condition, which makes the patient safer during surgery;4) A PC can control the two injection pumps, so the target concentration of two kinds of medicine can be updated at the same time and the system has the advantages of small volume, saving resources and better anesthetic effect;5) System programs are written with modular using Qt C++ high-level language, which is easy to optimize upgrade in the following time, as well as having friendly man-machine interface, used conveniently.In the Liberation Army XX Hospital clinical validation results show that through two anesthetic drug including propofol and remifentanil parallel channel test, the system can complete the infusion of anesthesia and the efficacy is superior than the traditional model.