Strebel S, Kaufmann M, Anselmi L, Schaefer H G
Department of Anaesthesia, University of Basel/Kantonsspital, Switzerland.
Acta Anaesthesiol Scand. 1995 Jul;39(5):653-8. doi: 10.1111/j.1399-6576.1995.tb04143.x.
Nitrous oxide during neurosurgical procedures is almost always given in combination with either volatile or intravenous anesthetics. The modifying influence of such interventions has been studied clinically and in experimental settings; the reported findings, however, are inconsistent. The present study compares the cerebrovascular effects of MAC equivalent concentrations of isoflurane alone and isoflurane plus nitrous oxide. Twenty lumbar laminectomy patients randomized either to receive isoflurane or isoflurane plus nitrous oxide were investigated over a dose range from 0.5 to 1.5 MAC. A transcranial Doppler (TCD) ultrasonography device was used to measure cerebral blood flow velocity (CBFV) in the right middle cerebral artery (MCA) as an index of anesthetic-induced alterations in cerebral blood flow (CBF). A small but marginally significant decrease in CBFV at 1 MAC and no change at 1.5 MAC occurred in the isoflurane anesthetized patients. In contrast, a small but significant increase in CBFV at 1 MAC and a very significant increase at 1.5 MAC occurred in the isoflurane plus nitrous oxide anesthetized patients. Nitrous oxide added to an isoflurane anesthetic regimen is concluded to be a potent vasodilator. In addition, the vasodilating effects of nitrous oxide were not uniform; they progressively increased with an increasing isoflurane concentration.
在神经外科手术过程中，一氧化二氮几乎总是与挥发性麻醉剂或静脉麻醉剂联合使用。这种联合干预的调节作用已在临床和实验环境中进行了研究；然而，报告的结果并不一致。本研究比较了等效最低肺泡浓度（MAC）的异氟烷单独使用和异氟烷加一氧化二氮时对脑血管的影响。对20例行腰椎椎板切除术的患者进行随机分组，分别接受异氟烷或异氟烷加一氧化二氮，研究剂量范围为0.5至1.5 MAC。使用经颅多普勒（TCD）超声设备测量右侧大脑中动脉（MCA）的脑血流速度（CBFV），作为麻醉引起的脑血流（CBF）变化的指标。接受异氟烷麻醉的患者在1 MAC时CBFV略有下降但具有边缘显著性，在1.5 MAC时无变化。相比之下，接受异氟烷加一氧化二氮麻醉的患者在1 MAC时CBFV有小幅但显著的增加，在1.5 MAC时有非常显著的增加。得出的结论是，在异氟烷麻醉方案中添加一氧化二氮是一种强效血管扩张剂。此外，一氧化二氮的血管扩张作用并不均匀；它们随着异氟烷浓度的增加而逐渐增强。
