Analyzing effects of sodium pentobarbital on hemodynamic responses by using a graphic control system

The maintenance of adequate anesthesia is very important for animal studies. This goal could be achieved if the pharmacokinetics of the anesthetic is known and a well-controlled instrument system is used. To this end, a graphic control system is developed to study the effects of sodium pentobarbital on anesthesia. Hemodynamic signals such as mean blood pressure, pulse pressure, heart rate were analyzed and used as index for quantitative evaluating the level of anesthesia. Factors that could affect the anesthesia, e.g. body weight (BW) of the rat and the concentration of pentobarbital were used as independent variables to examine the survival time (dependent variable) for an overdosage anesthesia. The relationship among the BW, the drug concentration, and the survival time before death were formulated. As most physiological system have shown, the empirical relationship is exponential in nature. This implies that the mechanism is highly nonlinear and it is complicated by the buffering characteristics of life. Hence, a precision feedback control system seems to be necessary for a well-controlled anesthesia.