Department of Anesthesiology and Intensive Care Medicine, University of Bonn, Sigmund Freud Str. 25, 53105 Bonn Germany.
Anesth Analg. 2013 Mar;116(3):580-8. doi: 10.1213/ANE.0b013e31827ced18. Epub 2013 Feb 11.
Recently the Composite Variability Index (CVI) was developed to quantify nociception. This index is derived from the standard deviations (s) of the Bispectral Index (sBIS) and the electromyogram (sEMG). The primary aim of our study was to compare CVI before and after a noxious stimulus. As secondary end points, we investigated the influence of remifentanil on the CVI and tested the ability of the CVI to indicate patient movement after a noxious stimulus under changing remifentanil concentrations. Furthermore, we measured the increase in CVI after a noxious stimulus in comparison to other clinical variables (BIS, sBIS, sEMG, heart rate [HR], and systolic blood pressure [BP(sys)]).
Twenty-four patients without a history of cardiac disease were investigated. Anesthesia was induced with propofol administered by target-controlled infusion. A standardized noxious electrical stimulus was applied (50 Hz, 70 mA, 30 seconds) to the ulnar nerve at increasing or decreasing remifentanil effect-compartment concentrations (Ce(remi)). Changes in baseline and poststimulus CVI, BIS, sBIS, sEMG, HR, and BP(sys) were investigated. Parameters' ability to indicate movement after a noxious stimulus was evaluated with the prediction probability (P(K)).
All investigated parameters (except BP(sys)) increased significantly after a noxious stimulus at 0, 1, 2, or 3 ng·mL(-1) Ce(remi). The association between poststimulus maximal parameters and movement were P(K) = 0.81 for HR, P(K) = 0.78 for sEMG, and P(K) = 0.72 for CVI (pairwise difference to CVI statistically nonsignificant). The association between ΔsEMG or ΔCVI (poststimulus value minus baseline value) and movement was significantly higher (P(K) = 0.76 and 0.75, respectively) compared with ΔHR (P(K) = 0.53) (P = 0.008 and P = 0.01, respectively). Receiver operating characteristic analysis revealed a threshold value for movement for ΔCVI of >0.39 (sensitivity of 0.71, specificity of 0.74) and for ΔsEMG of >0.31 (sensitivity of 0.68, specificity of 0.78).
In paralyzed patients, ΔsEMG and ΔCVI might help identify inadequately low levels of analgesia with an acceptable sensitivity and specificity. The impact of profound neuromuscular block on the CVI should be investigated in further studies.
最近开发了复合变异指数（CVI）来量化伤害感受。该指数源自脑电双频指数（sBIS）和肌电图（sEMG）的标准差（s）。本研究的主要目的是比较伤害性刺激前后的 CVI。作为次要终点，我们研究了瑞芬太尼对 CVI 的影响，并测试了 CVI 在瑞芬太尼浓度变化下指示伤害性刺激后患者运动的能力。此外，我们比较了其他临床变量（BIS、sBIS、sEMG、心率[HR]和收缩压[BP(sys)])后，测量了伤害性刺激后 CVI 的增加。
研究了 24 名无心脏病病史的患者。通过靶控输注给予丙泊酚诱导麻醉。在增加或减少瑞芬太尼效应室浓度（Ce(remi)）时，对尺神经施加标准化的伤害性电刺激（50 Hz，70 mA，30 秒）。研究了基线和刺激后 CVI、BIS、sBIS、sEMG、HR 和 BP(sys)的变化。使用预测概率（P(K)）评估参数指示伤害性刺激后运动的能力。
在 Ce(remi)为 0、1、2 或 3 ng·mL(-1)时，所有研究的参数（除 BP(sys)外）在伤害性刺激后均显著增加。刺激后最大参数与运动之间的关联为 HR 的 P(K) = 0.81、sEMG 的 P(K) = 0.78 和 CVI 的 P(K) = 0.72（与 CVI 的差异无统计学意义）。与 HR 的 P(K) = 0.53 相比，sEMG 或 CVI 的 Δ（刺激后值减去基线值）与运动之间的关联显著更高（P(K) = 0.76 和 0.75，分别）（P = 0.008 和 P = 0.01，分别）。接收者操作特征分析显示，运动的 CVI 阈值为 >0.39（敏感性为 0.71，特异性为 0.74），sEMG 的阈值为 >0.31（敏感性为 0.68，特异性为 0.78）。
在瘫痪患者中，ΔsEMG 和 ΔCVI 可能有助于以可接受的敏感性和特异性识别镇痛不足。应在进一步的研究中调查深度神经肌肉阻滞对 CVI 的影响。
