Calvo Vecino J M, Abad Gurumeta A, Garrido Reche E, Chao Novo K, Orts Castro A, Tomás Lachos J
Servicio de Anestesiología y Reanimación, Complejo Hospitalario de Vallecas, Hospital Infanta Leonor, Vallecas, Madrid.
Rev Esp Anestesiol Reanim. 2010 Dec;57(10):621-9. doi: 10.1016/s0034-9356(10)70298-x.
Transcranial Doppler ultrasound is a noninvasive technique for monitoring the velocity of blood flow in the main intracranial arteries, particularly those in the circle of Willis. Our aim was to assess whether changes in cerebral arterial blood flow in anesthetized pediatric patients detected by pulsed Doppler ultrasound correlate with changes in the bispectral (BIS) index and electroencephalographic state and response entropy (ES and ER, respectively).
Prospective, blinded observational study of 36 pediatric patients (age range, 5 to 11 years) under total intravenous anesthesia for minor surgical procedures. Propofol and fentanyl were used for induction; propofol and remifentanil in continuous perfusion and a single dose of cisatracurium were used for maintenance. In all patients we monitored hemodynamic and respiratory patterns, gases, temperature, and hypnosis (BIS, ES and ER) as well as cerebral blood flow estimated by pulsed Doppler ultrasound in the middle cerebral artery. Raw data were subjected to statistical smoothing. The resistance index, pulsatility index, mean velocity, and estimated baseline cerebral blood flow were calculated from the Doppler sonogram. We then studied the correlations between the Doppler-derived values and BIS, ES, ER, fraction of end-tidal carbon dioxide, and temperature. The variables were entered into logistic regression.
The pattern at induction indicated high resistance (low mean velocities and high pulsatility indexes) until the lowest BIS and ES values of 31 and 29, respectively, were reached. During maintenance, the Doppler sonogram pattern was slower (normalization of the pulsatility index, the resistance index, and mean velocity). Changes in flow and absolute entropy and BIS values were statistically correlated (Pearson's r values > or = 0.91); there was 95.6% agreement between Doppler values and BIS and agreement between BIS and ES values of 35-45. On awakening, flow velocities approached baseline values when BIS and ES rose to between 90 and 98. The estimated cerebral blood flow underwent fluctuations coinciding with an approximately concomitant increase or decrease in BIS (r > 0.95); the response of BIS was slightly delayed by no more than a minute but there was no corresponding response of entropy measurements.
We report Doppler ultrasound patterns during anesthesia with propofol. Systems for monitoring hypnosis could be considered indirect measurements of cerebral blood flow; BIS measurements are more sensitive to flow change. Transcranial Doppler ultrasound facilitates the observation of changes in blood flow that occur at different levels of hypnosis during anesthesia.
经颅多普勒超声是一种用于监测颅内主要动脉，尤其是 Willis 环中动脉血流速度的无创技术。我们的目的是评估脉冲多普勒超声检测到的麻醉小儿患者脑动脉血流变化是否与脑电双频指数（BIS）及脑电图状态和反应熵（分别为 ES 和 ER）的变化相关。
对 36 例年龄在 5 至 11 岁的小儿患者进行前瞻性、盲法观察研究，这些患者接受小手术的全静脉麻醉。丙泊酚和芬太尼用于诱导；丙泊酚和瑞芬太尼持续输注以及单次剂量的顺式阿曲库铵用于维持。在所有患者中，我们监测血流动力学和呼吸模式、气体、体温及催眠状态（BIS、ES 和 ER），以及通过脉冲多普勒超声估计的大脑中动脉脑血流量。原始数据进行了统计平滑处理。根据多普勒超声心动图计算阻力指数、搏动指数、平均速度及估计的基线脑血流量。然后我们研究了多普勒衍生值与 BIS、ES、ER、呼气末二氧化碳分数及体温之间的相关性。将这些变量纳入逻辑回归分析。
诱导期的模式显示高阻力（低平均速度和高搏动指数），直至分别达到最低的 BIS 和 ES 值 31 和 29。维持期，多普勒超声心动图模式较慢（搏动指数、阻力指数和平均速度正常化）。血流变化与绝对熵及 BIS 值在统计学上相关（Pearson 相关系数 r 值≥0.91）；多普勒值与 BIS 之间的一致性为 95.6%，BIS 与 ES 值在 35 - 45 之间具有一致性。苏醒时，当 BIS 和 ES 升至 90 至 98 之间时，血流速度接近基线值。估计的脑血流量出现波动，与 BIS 的大致相应增加或减少同时发生（r > 0.95）；BIS 的反应稍有延迟但不超过 1 分钟，而熵测量无相应反应。
我们报告了丙泊酚麻醉期间的多普勒超声模式。催眠监测系统可被视为脑血流量的间接测量；BIS 测量对血流变化更敏感。经颅多普勒超声有助于观察麻醉期间不同催眠水平下发生的血流变化。
