全凭体重计算两种药代动力学模型在病态肥胖患者中用于诱导和插管的有效效应部位丙泊酚浓度。

The effective effect-site propofol concentration for induction and intubation with two pharmacokinetic models in morbidly obese patients using total body weight.

机构信息

Departamento de Anestesiología, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.

出版信息

Anesth Analg. 2012 Oct;115(4):823-9. doi: 10.1213/ANE.0b013e31825d6254. Epub 2012 Sep 5.

DOI:10.1213/ANE.0b013e31825d6254

PMID:22956531

Abstract

BACKGROUND

Most pharmacokinetic (PK) models used for propofol administration are based on studies in normal-weight patients. Extrapolation of these models for morbidly obese patients is controversial. Using 2 PK models and a target-controlled infusion system, we determined the predicted propofol effect-site concentration (Ce) needed for induction of anesthesia in morbidly obese subjects using total body weight.

METHODS

Sixty-six morbidly obese subjects from 18 to 50 years of age were randomized to receive propofol to reach and maintain a predetermined propofol Ce, based on the PK models of either Marsh or Schnider. All patients were monitored with a Bispectral Index electroencephalographic monitor. Fentanyl 3 μg/kg total body weight was administered before starting the propofol infusion. After loss of consciousness, vecuronium was administered to facilitate endotracheal intubation. Groups of 6 patients each received propofol at a different, predetermined target propofol Ce. An "effective Ce" (ECe) was defined as the propofol Ce that provided adequate hypnosis (Bispectral Index <60) during the complete induction period (45 seconds after reaching the predetermined target Ce until 5 minutes after tracheal intubation). Heart rate and arterial blood pressure were measured every 1 minute throughout the study period. Probit regression analysis was performed to calculate the effective propofol Ce values to induce hypnosis in 50% (ECe(50)) and 95% (ECe(95)) of patients with 95% confidence intervals (CIs).

RESULTS

Patient characteristics were similar between models and across the propofol target concentration groups. The ECe(50) of propofol was 3.4 μg/mL (95% CI: 2.9, 3.7 μg/mL) with the Marsh model and 4.5 μg/mL (95% CI: 4.1, 4.8 μg/mL) with the Schnider model (P < 0.001). The ECe(95) values were 4.2 μg/mL (95% CI: 3.8, 6.2 μg/mL) and 5.5 μg/mL (95% CI: 5.0, 7.2 μg/mL) with Marsh and Schnider models, respectively. At the ECe(95), hemodynamic effects were similar with the 2 PK models.

CONCLUSION

Different propofol target concentrations for each PK model must be used for induction when using total body weight in morbidly obese patients.

摘要

背景

大多数用于丙泊酚给药的药代动力学（PK）模型都是基于正常体重患者的研究。将这些模型外推到病态肥胖患者存在争议。本研究使用 2 种 PK 模型和靶控输注系统，根据 Marsh 或 Schnider 的 PK 模型，用总体重来确定诱导病态肥胖患者麻醉所需的预测丙泊酚效应部位浓度（Ce）。

方法

66 例年龄 18-50 岁的病态肥胖患者被随机分为两组，分别接受丙泊酚输注，使丙泊酚 Ce 达到并维持在基于 Marsh 或 Schnider PK 模型预设的水平。所有患者均使用脑电双频指数（BIS）监测仪进行监测。给予患者 3μg/kg 总重的芬太尼，然后开始输注丙泊酚。当患者意识丧失后，给予维库溴铵以方便气管插管。每组 6 例患者，分别接受不同的、预设的丙泊酚靶 Ce。定义“有效 Ce”（ECe）为在整个诱导期（达到预定靶 Ce 后 45 秒至气管插管后 5 分钟）提供足够催眠作用（BIS <60）的丙泊酚 Ce。在整个研究期间，每 1 分钟测量一次心率和动脉血压。采用概率回归分析计算诱导 50%（ECe(50)）和 95%（ECe(95)）患者所需的有效丙泊酚 Ce 值，置信区间为 95%。

结果

两种模型和丙泊酚靶浓度组的患者特征相似。Marsh 模型的丙泊酚 ECe(50)为 3.4μg/ml（95%CI：2.9, 3.7μg/ml），Schnider 模型为 4.5μg/ml（95%CI：4.1, 4.8μg/ml）（P<0.001）。Marsh 和 Schnider 模型的 ECe(95)值分别为 4.2μg/ml（95%CI：3.8, 6.2μg/ml）和 5.5μg/ml（95%CI：5.0, 7.2μg/ml）。在 ECe(95)时，两种 PK 模型的血液动力学效应相似。