From the *Department of Anaesthesiology, University of Auckland, Auckland, New Zealand; †Department of Anaesthesia, Auckland City Hospital, Auckland, New Zealand; and ‡Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
Anesth Analg. 2016 Jan;122(1):90-7. doi: 10.1213/ANE.0000000000000386.
Propofol and remifentanil are commonly combined for total IV anesthesia. The pharmacokinetics (PK), pharmacodynamics (PD), and drug interactions of the combination are well understood, but the use of a combined PK and PD model to control target-controlled infusion pumps has not been investigated. In this study, we prospectively tested the accuracy of a PD target-controlled infusion algorithm for propofol and remifentanil using a response surface model of their combined effects on Bispectral Index (BIS).
Effect-site, target-controlled infusions of propofol and remifentanil were given using an algorithm based on standard PK models linked to a PD response surface model of their combined effects on BIS. The combination of a targeted BIS value and adjustable ratio of propofol to remifentanil was used to adjust infusion rates. The standard model performance measures of median performance error (bias) and median absolute performance error (inaccuracy), expressed as percentages, were used to assess accuracy of the infusions in a convenience sample of 50 adult patients undergoing surgery with general anesthesia. The influence of age and weight on the performance of the model was also assessed.
Patients had a mean (range) age of 48 (19-73) years, weight of 80 (45-169) kg, and body mass index of 28 (19-45) kg/m. The overall model had a bias of 8% (SD 24%) and inaccuracy of 25% (SD 13%). Performance was least accurate during the early induction phase of anesthesia. There was no significant bias in BIS predictions with increasing age (P = 0.44) or weight (P = 0.56).
The algorithm performed adequately in a clinical setting. The algorithm could be further refined, and assessment of its accuracy and utility in comparison to current clinical practice for giving IV anesthesia is warranted.
丙泊酚和瑞芬太尼常联合用于全凭静脉麻醉。该联合用药的药代动力学（PK）、药效动力学（PD）和药物相互作用已得到充分了解，但尚未研究使用联合 PK 和 PD 模型来控制靶控输注泵。在这项研究中，我们前瞻性地测试了一种 PD 靶控输注算法控制丙泊酚和瑞芬太尼的准确性，该算法使用其对脑电双频指数（BIS）联合作用的响应曲面模型。
使用基于标准 PK 模型的效应部位、靶控输注丙泊酚和瑞芬太尼，并与 BIS 联合作用的 PD 响应曲面模型相连接。使用目标 BIS 值和丙泊酚与瑞芬太尼的可调比例来调整输注速度。使用标准模型性能指标的中位数性能误差（偏差）和中位数绝对性能误差（不准确性），以百分比表示，评估 50 名接受全身麻醉手术的成年患者的便利样本中输注的准确性。还评估了年龄和体重对模型性能的影响。
患者的平均（范围）年龄为 48（19-73）岁，体重为 80（45-169）kg，体重指数为 28（19-45）kg/m。总体模型的偏差为 8%（SD 24%），不准确性为 25%（SD 13%）。麻醉早期诱导阶段的性能最不准确。BIS 预测的偏差与年龄（P = 0.44）或体重（P = 0.56）的增加无关。
该算法在临床环境中表现良好。需要进一步改进该算法，并评估其在与当前 IV 麻醉给药临床实践相比的准确性和实用性。
