Tsuchiya S, Kanaya N, Hirata N, Kurosawa S, Kamada N, Edanaga M, Nakayama M, Omote K, Namiki A
Department of Anesthesiology, School of Medicine, Sapporo Medical University, Sapporo, Japan.
Eur J Anaesthesiol. 2006 Jun;23(6):454-9. doi: 10.1017/S0265021506000159. Epub 2006 Mar 1.
Thiopental has been reported to reduce sympathetic tone, however, it is not clear whether change in heart rate variability is associated with depth of anaesthesia. The purpose of the present study was to evaluate changes in heart rate variability at different depths of hypnosis during induction of anaesthesia with thiopental.
We studied 17 ASA I patients scheduled for minor surgery. The depth of hypnosis was monitored by the BIS. Spectral analysis of heart rate variability using a maximum entropy method resulted in a characteristic power spectrum with two main regions, a high frequency and a low frequency. Haemodynamics, entropy, low frequency, high frequency and low frequency/high frequency were monitored in an awake state and after the induction of anaesthesia.
Heart rate increased in a BIS-dependent manner, whereas blood pressure showed no significant changes during the study period. High frequency, entropy and low frequency decreased with a reduction in the BIS value. Low frequency/high frequency showed no significant change during the study period.
Induction of anaesthesia with thiopental increased heart rate and decreased high frequency, entropy and low frequency in a BIS-dependent manner, indicating that thiopental reduces cardiac parasympathetic tone depending on the depth of hypnosis.
据报道，硫喷妥钠可降低交感神经张力，然而，心率变异性的变化是否与麻醉深度相关尚不清楚。本研究的目的是评估硫喷妥钠诱导麻醉期间不同催眠深度下心率变异性的变化。
我们研究了17例计划进行小手术的美国麻醉医师协会（ASA）I级患者。通过脑电双频指数（BIS）监测催眠深度。使用最大熵方法对心率变异性进行频谱分析，得到一个具有两个主要区域的特征功率谱，即高频和低频。在清醒状态和麻醉诱导后监测血流动力学、熵、低频、高频以及低频/高频。
心率以依赖BIS的方式增加，而在研究期间血压无显著变化。随着BIS值降低，高频、熵和低频均下降。低频/高频在研究期间无显著变化。
硫喷妥钠诱导麻醉以依赖BIS的方式增加心率并降低高频、熵和低频，表明硫喷妥钠根据催眠深度降低心脏副交感神经张力。
