Effects of Propofol Induction Anaesthesia on the Heart Rate Variability

Because the ANS, especially the sympathetic nervous system, plays a major role in regulating cardiovascular homeostasis, knowledge of how anesthetic agents modify sympathetic activity is important for understanding subsequent cardiovascular responses.

Spectral analysis of heart rate variability (HRV) is a promising new approach, widely used, noninvasive technique to assess the autonomic indexes of neural cardiac control and has been correlated to the integrity and balance of the sympathetic and parasympathetic activation status. The presence of low-frequency (LF) and high-frequency (HF) oscillatory rhythms in the variability of the R-R interval (RRI) is well established. To date, it is believed that LF is mediated by the parasympathetic and sympathetic systems, whereas HF is mediated primarily by the parasympathetic system. There has been a lot of methodological analysis developed to evaluate the ANS function during anesthesia. In this study, Continuous Wavelet Transform (CWT), believed as a reliable and robust method to access cardiorespiratory dynamics of the ANS due to its adaptability and adjustability between spectral and temporal scale using a window of variable width, was used as a method for analyzing dynamic cardiovascular signals during anesthesia.

Inclusion criteria

• The subjects were selected from patients scheduled for surgery under general anesthesia.

Exclusion criteria

• recent administration of sedative or opioid drugs, emergency surgery and impairment of renal, hepatic, cardiac or respiratory function.