Continuous wavelet analysis of heart rate variability during general anesthesia / 生物医学工程学杂志

ABSTRACT

The depth of anesthesia can be assessed by means of analyzing heart rate variability (HRV). Continuous wavelet transform (CWT) was used to obtain more accurate results on the changes of low frequency (LF) and high frequency (HF) components of HRV signals (RR interval sequences) before and after general anesthesia. With wavelet scale transformed into frequency, the obtained time-frequency energy distributions showed that the LF and HF components of HRV signals were suppressed after general anesthesia, while the LF/HF ratio reduced from 9.0219 to 3.5573. The time-frequency distribution showed that CWT can more accurately locate the abrupt changes in time-domain, giving more precise range of frequency changing, compared with traditional time-frequency analysis method. The results indicated that, as a new time-frequency analysis method of analyzing HRV during general anesthesia, CWT provides more accurate time-frequency location, and consequently, offers more accurate monitoring results of anesthesia depth.