A NEW APPROACH TO SOLVING GENERAL ANAESTHESIA INDIVIDUALIZATION PROBLEM DURING SURGICAL OPERATIONS WITH CARDIOPULMONARY BYPASS

Abstract

The computerized system to control depth of anesthesia during surgical operation was developed in our research center. The depth of anesthesia is regulated by controlled intravenous infusion of propofol. The varied propofol rate is controlled by the closed-loop propofol system (CLPS) with mean arterial pressure (MAP) controller. MAP is used in the CLPS as input parameter and indicator of anesthesia depth. CLPS consists PC, invasive blood pressure (BP) sensor and Graseby 3400 infusion pump. The C language computer program sets the propofol infusion rate based on empirical algorithm including proportional component to maintain the measured MAP more closely to the target MAP (85% of patient standard MAP). The propofol concentrations are calculated by Runge–Kutta’s method PK/PD model differential equations solving with Marsh’s microconstants and Kazama’s BIS effect site microconstant and age depended BP effect site microconstants every 30 s. The designed CLPS was effective and useful for anesthesia maintenance during open-heart surgery, especially for early extubation.

Keywords

• closed-loop system
• propofol
• automatic anesthesia