Increased non-stationarity of heart rate during general anaesthesia with sevoflurane or desflurane in children.

Abstract

During general anaesthesia, the most prominent change in heart rate variability (HRV) is a decrease in the magnitude of heart rate (HR) oscillation in the high- and low-frequency ranges. In children receiving sevoflurane or desflurane, we observed a significant increase in HR non-stationarity, that is, a significant change of mean HR over time. The aim of our study was to describe this increased non-stationarity and compare it with the decrease in the magnitude of HR oscillation. Sixty children received sevoflurane (n=30) or desflurane anaesthesia (n=30). The magnitude of HR oscillation and non-stationarity during pre-anaesthesia and anaesthesia were measured by spectral and Hurst analyses using structure function, respectively. Low- and high-frequency powers decreased significantly and the very-short-term (2<or=tau<or=8 s, H(alpha)) and short-term Hurst exponent (8<or=tau<or=45 s, H(beta)) increased significantly during the anaesthetic period compared with the pre-anaesthetic period, regardless of the anaesthetic agent [sevoflurane: mean (sd) H(alpha) 0.414 (0.169) vs 0.252 (0.0655), H(beta) 0.481 (0.169) vs 0.078 (0.0409); desflurane H(alpha) 0.336 (0.171) vs 0.261 (0.0614), H(beta) 0.471 (0.221) vs 0.0813 (0.049)]. Stepwise discriminant analysis showed that the short-term Hurst exponent was better than the spectral indices at differentiating between the pre-anaesthetic period and anaesthetic period. During sevoflurane and desflurane anaesthesia in children, there is a significant increase in very-short-term and short-term HR non-stationarity. Furthermore, the greater short-term non-stationarity differentiates better between the pre-anaesthesia and anaesthesia than the decreased magnitude of HR oscillation in the high- and low-frequency ranges.