College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China.
Key Lab of Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou, China.
J Clin Monit Comput. 2021 Apr;35(2):297-305. doi: 10.1007/s10877-020-00470-6. Epub 2020 Feb 5.
The ability to monitor the physiological effect of the analgesic agent is of interest in clinical practice. Nonstationary changes would appear in photoplethysmography (PPG) during the analgesics-driven transition to analgesia. The present work studied the properties of nonlinear methods including approximate entropy (ApEn) and sample entropy (SampEn) derived from PPG responding to a nociceptive stimulus under various opioid concentrations. Forty patients with ASA I or II were randomized to receive one of the four possible remifentanil effect-compartment target concentrations (Ce) of 0, 1, 3, and 5 ng·ml and a propofol effect-compartment target-controlled infusion to maintain the state entropy (SE) at 50 ± 10. Laryngeal mask airway (LMA) insertion was applied as a standard noxious stimulation. To optimize the performance of ApEn and SampEn, different coefficients were carefully evaluated. The monotonicity of ApEn and SampEn changing from low Ce to high Ce was assessed with prediction probabilities (P). The result showed that low Ce (0 and 1 ng·ml) could be differentiated from high Ce (3 and 5 ng·ml) by ApEn and SampEn. Depending on the coefficient employed in algorithm: ApEn with k = 0.15 yielded the largest P value (0.875) whereas SampEn gained its largest P of 0.867 with k = 0.2. Thus, PPG-based ApEn and SampEn with appropriate k values have the potential to offer good quantification of analgesia depth under general anesthesia.
监测镇痛剂生理效应的能力在临床实践中很有意义。在镇痛药物作用下向镇痛状态的转变过程中，光体积描记法（PPG）会出现非平稳变化。本研究探讨了非线性方法的特性，包括近似熵（ApEn）和样本熵（SampEn），这些方法来自于对不同阿片类药物浓度下的伤害性刺激的 PPG 响应。40 名 ASA I 或 II 级患者被随机分为四组，分别接受四种可能的瑞芬太尼效应室靶浓度（Ce）中的一种：0、1、3 和 5ng·ml，以及丙泊酚效应室靶控输注，以维持状态熵（SE）在 50±10。喉罩气道（LMA）插入作为标准的伤害性刺激。为了优化 ApEn 和 SampEn 的性能，仔细评估了不同的系数。通过预测概率（P）评估 ApEn 和 SampEn 从低 Ce 到高 Ce 单调变化的情况。结果表明，低 Ce（0 和 1ng·ml）可以通过 ApEn 和 SampEn 与高 Ce（3 和 5ng·ml）区分开来。根据算法中使用的系数：ApEn 中 k=0.15 产生的 P 值最大（0.875），而 SampEn 中 k=0.2 时 P 值最大，为 0.867。因此，基于 PPG 的 ApEn 和 SampEn 具有适当的 k 值，有潜力在全身麻醉下提供良好的镇痛深度定量。
