Chang C C, Yang M W, Lin S M, Kuo T B, Chan K H, Lin C Y
Department of Anesthesiology, Veterans General Hospital-Taipei, Taiwan, R.O.C.
Zhonghua Yi Xue Za Zhi (Taipei). 1995 Jun;55(6):421-6.
The close relationship between the balance of sympathetic and parasympathetic tones and the results of power spectral analysis (PSA) of systemic arterial pressure (SAP) has been suggested recently. The purpose of this study was to further describe the changes of balance between the two autonomic nervous components during open heart surgery for coronary arterial disease (CAD) or valvular heart disease (VHD) with the PSA technique of SAP.
By relaying the SAP signals to a personal computer utilizing a power spectral analysis algorithm, radial arterial pressure signals of 27 patients (11 with CAD for coronary artrial bypass graft, as CAD groups; 16 with VHD, as VHD group, including 8 for aortic valve replacement and 8 for mitral valve replacement) during open heart surgery were monitored in a continuous, on-line and real-time manner. On-line power spectral analysis was performed according to the five different stages of the operation.
Power density tended to increase in the high frequency (HF) band during the ventilator-supported stages of the open heart procedures, i.e., the pre-cardiopulmonary bypass (CPB) and the off-CPB periods. The power density in other frequency bands during the whole course of general anesthesia otherwise decreased significantly, with the lowest values occurring during CPB. The power density in very low frequency (VLF) band was much higher than in other bands during CPB, and became the major component of total power density in this period.
The balance between sympathetic and parasympathetic components of autonomic nervous system changes rapidly during open heart surgery and needs careful monitoring. By utilizing PSA of SAP, mathematical error might be an obstacle of using LF:HF ratio as an index of autonomic balance during the CPB period when the HF density approaches zero.
最近有人提出，交感神经和副交感神经张力平衡与体动脉压（SAP）的功率谱分析（PSA）结果之间存在密切关系。本研究的目的是利用SAP的PSA技术，进一步描述冠状动脉疾病（CAD）或心脏瓣膜病（VHD）心脏直视手术期间这两种自主神经成分之间平衡的变化。
通过使用功率谱分析算法将SAP信号传输到个人计算机，对27例患者（11例因冠状动脉搭桥术患有CAD，作为CAD组；16例患有VHD，作为VHD组，包括8例进行主动脉瓣置换和8例进行二尖瓣置换）在心脏直视手术期间的桡动脉压信号进行连续、在线和实时监测。根据手术的五个不同阶段进行在线功率谱分析。
在心脏直视手术的呼吸机支持阶段，即体外循环（CPB）前和CPB后阶段，高频（HF）频段的功率密度趋于增加。全身麻醉全过程中其他频段的功率密度则显著降低，最低值出现在CPB期间。CPB期间极低频（VLF）频段的功率密度远高于其他频段，并成为该时期总功率密度的主要组成部分。
心脏直视手术期间自主神经系统交感神经和副交感神经成分之间的平衡变化迅速，需要仔细监测。通过利用SAP的PSA，当HF密度接近零时，数学误差可能是在CPB期间将低频：高频比值用作自主神经平衡指标的一个障碍。
