Loula P, Jäntti V, Yli-Hankala A
Tampere University of Technology, Pori, Finland.
Int J Clin Monit Comput. 1997 Nov;14(4):241-9. doi: 10.1007/BF03356569.
Beat-to-beat heart rate variability analysis is a powerful tool for the diagnosis of neuropathy. Respiration-related heart rate variability (respiratory sinus arrhythmia, RSA) reflects the function of parasympathetic nervous system during spontaneous ventilation while awake. RSA is also claimed to monitor the depth of anaesthesia. Power spectrum analysis or various averaging techniques of the heart rate variability are usually applied. The current literature, however, does not usually interpret the ground rules and limitations of the method used, and this may sometimes lead to erroneous conclusions on the data. The aim of our study was to compare and analyse critically the performance of different methods of evaluating RSA during anaesthesia and positive pressure ventilation. Power spectrum analysis, the root mean square of the successive RR-interval difference (RMSSD), and two respiration related methods, RSA index and average phase RSA, were included in the comparison. To test these methods, 11 patients were anaesthetised with isoflurane and their lungs were ventilated mechanically with a frequency of 6 cycles min-1. Each patient received a bolus dose of atropine (20 micrograms kg-1) during the trial. Electrocardiogram, electroencephalogram and tracheal pressure signal from respirator were recorded and analyses were performed off-line. We demonstrated that general indices, such as RMSSD, may be strongly affected by heart rate level and other non-respiration related variations in heart rate. We also showed that the effect of unwanted fluctuations on RSA can be reduced with respiration dependent beat-to-beat methods. Furthermore we confirmed that in addition to the amplitude, also the pattern of respiratory sinus arrhythmia is of interest: the pattern is reversed in phase compared to spontaneous breathing while awake, as we have shown earlier. To analyse RSA during anaesthesia, we recommend the use of an average phase RSA method based on beat-to-beat variability that shows both the amplitude and pattern of RSA. Finally, no measure of RSA should be used without a presentation of the actual beat-to-beat heart rate curve.
逐搏心率变异性分析是诊断神经病变的有力工具。呼吸相关心率变异性（呼吸性窦性心律不齐，RSA）反映了清醒时自主通气过程中副交感神经系统的功能。RSA也被认为可用于监测麻醉深度。通常采用心率变异性的功率谱分析或各种平均技术。然而，当前文献通常并未对所使用方法的基本规则和局限性进行阐释，这有时可能导致对数据得出错误结论。我们研究的目的是对麻醉和正压通气期间评估RSA的不同方法的性能进行比较和批判性分析。比较中纳入了功率谱分析、连续RR间期差值的均方根（RMSSD）以及两种与呼吸相关的方法，即RSA指数和平均相位RSA。为测试这些方法，对11例患者使用异氟烷进行麻醉，并以每分钟6次的频率对其肺部进行机械通气。在试验过程中，每位患者均接受一剂推注阿托品（20微克/千克）。记录心电图、脑电图以及来自呼吸机的气管压力信号，并进行离线分析。我们证明，诸如RMSSD等一般指标可能会受到心率水平以及其他与呼吸无关的心率变化的强烈影响。我们还表明，采用依赖呼吸的逐搏方法可以减少不必要波动对RSA的影响。此外，我们证实，除了幅度之外，呼吸性窦性心律不齐的模式也值得关注：正如我们之前所表明的，该模式在相位上与清醒时的自主呼吸相反。为分析麻醉期间的RSA，我们建议使用基于逐搏变异性的平均相位RSA方法，该方法可显示RSA的幅度和模式。最后，在未呈现实际逐搏心率曲线的情况下，不应使用任何RSA测量方法。
