Extraction of Dynamic in Brain Signal at Different Anesthesia States using Poincare Plot Analysis

Aims and Poincare plot and its length and width are known as a criterion for short-term variations of electroencephalogram signals )EEGs(. This study evaluates the effect of time delay on changes in the width of the Poincare plot in brain signal during different anesthesia states. Poincare plots are drawn with one to six delay in three sets, including awake state, light anesthesia, and general anesthesia, and also for each data, the width of the Poincare plot is calculated using the SD1 and SD2characteristics. Findings: The results show that during general anesthesia, the width of the Poincare plot increases with increasing latency. During anesthesia, the width of the Poincare plot is achieved by applying a unit delay of 8.1 ± 1.2 and a six-unit delay of 15.9 ± 0.8. Also, the Poincare plot is shifted to lower values during anesthesia. It is also shown that with increasing delay in general anesthesia, the SD1 value increase rate is higher than the previous ones, such as light anesthesia and awake state. Simplicity of calculating the width of the Poincare plot and its adaptation to the chaotic nature of vital signals can be useful in evaluating the brain signal in different states of anesthesia.