Secondary Logo

Journal Logo

Time-frequency spectral analysis of heart rate variability during halothane induction in pediatric patients

Li, C.-Y.1; Chou, T.-C.2; Wong, C.-S.1

European Journal of Anaesthesiology: 2000 - Volume 17 - Issue - p 20-21
European Society of Anaesthesiologists; 8th Annual Meeting with the Austrian International Congress; Vienna, Austria, 1-4 April 2000

1Department of Anaesthesiology, Tri-Service General Hospital, 2Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan, ROC

Abstract A-66

Background and goal of study: Heart Rate Variability (HRV) monitors the fluctuations of autonomic nervous system (ANS) outflow to the heart as well as the balance between its components (sympathetic and parasympathetic). It is known that the HRV characteristic changes differently under different methods of anaesthesia. However, it is unclear how HRV is influenced during halathane induction in children. In this study, an advanced time-frequency spectral analysis was used to examine the dynamic changes of spectral components during halothane induction in pediatric patients.

Materials and methods: Thirty ASA 1 patients (3-6 years), scheduled for elective surgery, were randomly allocated into three groups. The anaesthesia was induced with 3% halothane in 6 L of O2/N2O (2:3) and endotracheal intubation was performed. The effect of 10, 15 and 20 minutes (three groups) halothane induction on spectra power was examined at the following periods: (1) baseline, immediately after induction (2) preintubation (3) postintubation and (4) maintenance phases. Multiple spectra were generated to demonstrate the time-related spectral components of HRV by MATLAB (MathWrks Inc., MA, USA). One-way ANOVA was used for the statistic analysis.

Results and discussion: The time-frequency analysis method can generate multiple spectra continuously, we can observe the change in HRV during different time segments in the induction phase. In our study, marked reductions in the power of HRV spectra (low frequency 0.04-0.15 Hz, high frequency 0.15-0.4 Hz, and total power) were found after halothane induction. A significant increase in LF/HF ratio after intubation in 10-min group suggests that sympathetic nervous system activation is not blocked totally by halothane. The fluctuations in the power of LF and HF after intubation in the 20-min group were significantly lower than the other two groups. It indicates a better anaesthetic depth for endotracheal intubation.

Conclusion: Time-frequency spectral analysis of HRV is a useful tool for continuously assessing the dynamic changes of the ANS. Twenty minutes halothane inhalation may attenuate the sympathetic response of endotracheal intubation in pediatric patients.

Back to Top | Article Outline


1 Br J Anaesth79: 754-8, 1997.

    Section Description

    The abstracts published in this supplement have been typeset from camera-ready copies prepared by the authors. Every effort has been made to reproduce faithfully the abstracts as submitted. However, no responsibility is assumed by the organisers for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of methods, products, instructions or ideas contained in the material herein. Because of the rapid advances in medical sciences, we recommend that independent verification of diagnoses and drug doses should be made.

    Patient safety, equipment, monitoring and computers

    © 2000 European Society of Anaesthesiology