Lin Y-T, Wu H-T, Tsao J, Yien H-W, Hseu S-S
Department of Anesthesiology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan; Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan.
Acta Anaesthesiol Scand. 2014 Feb;58(2):157-67. doi: 10.1111/aas.12251.
Heart rate variability (HRV) may reflect various physiological dynamics. In particular, variation of R-R peak interval (RRI) of electrocardiography appears regularly oscillatory in deeper levels of anaesthesia and less regular in lighter levels of anaesthesia. We proposed a new index, non-rhythmic-to-rhythmic ratio (NRR), to quantify this feature and investigated its potential to estimate depth of anaesthesia.
Thirty-one female patients were enrolled in this prospective study. The oscillatory pattern transition of RRI was visualised by the time-varying power spectrum and quantified by NRR. The prediction of anaesthetic events, including skin incision, first reaction of motor movement during emergence period, loss of consciousness (LOC) and return of consciousness (ROC) by NRR were evaluated by serial prediction probability (PK ) analysis; the ability to predict the decrease of effect-site sevoflurane concentration was also evaluated. The results were compared with Bispectral Index (BIS).
NRR well-predicted first reaction (PK > 0.90) 30 s ahead, earlier than BIS and significantly better than HRV indices. NRR well-correlated with sevoflurane concentration, although its correlation was inferior to BIS, while HRV indices had no such correlation. BIS indicated LOC and ROC best.
Our findings suggest that NRR provides complementary information to BIS regarding the differential effects of anaesthetics on the brain, especially the subcortical motor activity.
心率变异性（HRV）可能反映各种生理动态。特别是，心电图R-R峰间期（RRI）的变化在较深麻醉水平时呈现规则振荡，而在较浅麻醉水平时则不太规则。我们提出了一种新的指标，即非节律性与节律性比率（NRR），以量化这一特征，并研究其估计麻醉深度的潜力。
31名女性患者参与了这项前瞻性研究。RRI的振荡模式转变通过时变功率谱进行可视化，并通过NRR进行量化。通过序列预测概率（PK）分析评估NRR对麻醉事件的预测，包括皮肤切开、苏醒期运动反应的首次出现、意识丧失（LOC）和意识恢复（ROC）；还评估了预测效应室七氟醚浓度降低的能力。将结果与脑电双频指数（BIS）进行比较。
NRR能提前30秒很好地预测首次反应（PK>0.90），比BIS更早，且显著优于HRV指标。NRR与七氟醚浓度相关性良好，尽管其相关性不如BIS，而HRV指标则无此相关性。BIS对LOC和ROC的指示效果最佳。
我们的研究结果表明，NRR在麻醉药对大脑尤其是皮质下运动活动的不同影响方面，为BIS提供了补充信息。
