Brenet O, Granry J C, Poirier N, Le Gall R
Département d'anesthésie-réanimation, CHU, Angers, France.
Ann Fr Anesth Reanim. 1998;17(3):227-33. doi: 10.1016/s0750-7658(98)80004-x.
To assess in children with a transcranial Doppler the effect on cerebral blood flow velocities of desflurane, whose cerebral vasodilator effects have been studied in animals and in adults with intracranial lesions.
Prospective clinical study.
Ten healthy children, mean age: 3.4 yr, ASA physical class 1, undergoing minor urologic surgery, were included in this study.
Induction was obtained with atropine 10 micrograms.kg-1, fentanyl 3 micrograms.kg-1 and propofol 3 mg.kg-1. Endotracheal intubation was facilitated by atracurium 0.3 mg.kg-1. Mechanical ventilation, with a 50% air/oxygen mixture was adjusted to achieve an end-tidal CO2 (PETCO2) level of 38 +/- 2 mmHg. Monitoring included measurement of mean arterial blood pressure (MAP), heart rate, PETCO2, SpO2 and end-tidal desflurane concentrations (FETDes). Mean blood flow velocities (Vmean) were measured in the middle cerebral artery using a bi-directional 2 MHz TCD system (EME-TC 2000 S). A first TCD measurement followed intubation (T1). Thereafter, desflurane was adjusted to 1 MAC. Six other TCDs were recorded each minute until FETDes reached the inspired fraction (T2-T7). Thereafter, CO2 reactivity was assessed with a hypocapnia test, induced by hyperventilation. Measures were done at T8 (PETCO2: 33 +/- 1 mmHg), T9 (PETCO2: 29 +/- 1 mmHg), and T10 (initial PETCO2: 38 +/- 1 mmHg). All these measurements were made before starting surgery. Analysis of variance (ANOVA) was used to analyse the data (P < 0.05 was considered as significant).
The Vmean and heart rate increased significantly with increasing concentrations of desflurane (Vmean from 68 +/- 27 to 106 +/- 30 cm.s-1 and heart rate from 109 +/- 17 to 136 +/- 15 b.min-1 between T1 and T7). During hypocapnia, Vmean decreased to 68 +/- 23 cm.s-1 at T9, and returned to normal values with PETCO2 at 38 mmHg at T10. SpO2 remained unchanged. Mean arterial pressure was stable from T1 to T7, but decreased significantly at T9 and T10.
Desflurane elicits a dose-dependent increase in cerebral blood flow velocities and heart rate, but does not change mean arterial pressure, suggesting that its cerebrovascular action is independent of its systemic vascular action. CO2 reactivity is maintained at one MAC. The results in children are similar to those seen in adults.
在小儿患者中应用经颅多普勒评估地氟醚对脑血流速度的影响，地氟醚的脑血管扩张作用已在动物及患有颅内病变的成人中进行过研究。
前瞻性临床研究。
本研究纳入了10名健康儿童，平均年龄3.4岁，ASA身体状况分级为1级，接受小型泌尿外科手术。
给予阿托品10微克·千克⁻¹、芬太尼3微克·千克⁻¹和丙泊酚3毫克·千克⁻¹进行诱导。阿曲库铵0.3毫克·千克⁻¹辅助气管插管。采用50%空气/氧气混合气体进行机械通气，调整通气量以使呼气末二氧化碳（PETCO₂）水平维持在38±2毫米汞柱。监测指标包括平均动脉血压（MAP）、心率、PETCO₂、脉搏血氧饱和度（SpO₂）和呼气末地氟醚浓度（FETDes）。使用双向2兆赫兹经颅多普勒系统（EME-TC 2000 S）测量大脑中动脉的平均血流速度（Vmean）。插管后进行首次经颅多普勒测量（T1）。此后，将地氟醚调整至1个最低肺泡有效浓度（MAC）。在FETDes达到吸入浓度之前，每分钟记录另外6次经颅多普勒测量结果（T2-T7）。此后，通过过度通气诱导低碳酸血症试验评估二氧化碳反应性。在T8（PETCO₂：33±1毫米汞柱）、T9（PETCO₂：29±1毫米汞柱）和T10（初始PETCO₂：38±1毫米汞柱）进行测量。所有这些测量均在手术开始前进行。采用方差分析（ANOVA）分析数据（P<0.05认为具有统计学意义）。
随着地氟醚浓度增加，Vmean和心率显著升高（T1至T7期间，Vmean从68±27厘米·秒⁻¹增至106±30厘米·秒⁻¹，心率从109±17次·分钟⁻¹增至136±15次·分钟⁻¹）。在低碳酸血症期间，T9时Vmean降至68±23厘米·秒⁻¹，T10时PETCO₂为38毫米汞柱时恢复至正常水平。SpO₂保持不变。平均动脉压从T1至T7保持稳定，但在T9和T10时显著下降。
地氟醚可引起脑血流速度和心率呈剂量依赖性增加，但不改变平均动脉压，提示其脑血管作用独立于其全身血管作用。在1个MAC时二氧化碳反应性得以维持。儿童中的结果与成人相似。
