Petersen Kurt D, Landsfeldt Uffe, Cold Georg Emil, Petersen Carsten B, Mau Søren, Hauerberg John, Holst Peter, Olsen Karsten Skovgaard
Department of Anesthesia and Neurosurgery, Aarhus University Hospital, Denmark.
Anesthesiology. 2003 Feb;98(2):329-36. doi: 10.1097/00000542-200302000-00010.
A critical point during craniotomy is opening of dura, where a high intracranial pressure (ICP) results in swelling of cerebral tissue. Controlled studies concerning ICP, degree of dural tension, and degree of cerebral swelling are therefore warranted.
In an open-label study, 117 patients with supratentorial cerebral tumors were randomized to propofol-fentanyl (group 1), isoflurane-fentanyl (group 2), or sevoflurane-fentanyl anesthesia (group 3). Normo- to moderate hypocapnia was applied, with a target level of arterial carbon dioxid tension of 30-40 mmHg. Mean arterial blood pressure was stabilized with intravenous ephedrine (2.5-5 mg) if necessary. Subdural ICP, mean arterial blood pressure, cerebral perfusion pressure (CPP), arteriovenous oxygen difference (AVDo2), internal jugular vein oxygen saturation were monitored before and after a 10-min period of hyperventilation, and the carbon dioxide reactivity was calculated. Furthermore, the tension of dura before and during hyperventilation and the degree of cerebral swelling during hyperventilation and after opening of the dura were estimated by the neurosurgeon.
No differences were found between groups with regard to demographics, neuroradiologic examination, positioning of the head, and time to ICP measurement. Before and during hyperventilation, ICP was significantly lower and mean arterial blood pressure and CPP significantly higher in group 1 compared with groups 2 and 3 (P < 0.05). The tension of dura before and during hyperventilation was significantly lower in group 1 compared with group2 (P < 0.05), but not significantly different from group 3. In group 1, cerebral swelling after opening of dura was significantly lower compared with groups 2 and 3 (P < 0.05). Furthermore, AVDo was significantly higher and jugular vein oxygen saturation and carbon dioxide reactivity were significantly lower in group 1 compared with groups 2 and 3 (P < 0.05). No significant differences with regard to ICP, CPP, AVDo, carbon dioxide reactivity, and jugular vein oxygen saturation were found between patients anesthetized with isoflurane and sevoflurane.
The study indicates that before as well as during hyperventilation, subdural ICP and AVDo2 are lower and CPP higher in propofol-anesthetized patients compared with patients anesthetized with isoflurane or sevoflurane. These findings were associated with less tendency for cerebral swelling after opening of dura in the propofol group. The carbon dioxide reactivity in patients anesthetized with isoflurane and sevoflurane was significantly higher than in the propofol group. The differences in subdural ICP between the groups are presumed to be caused by differences in the degree of vasoconstriction elicited by the anesthetic agents, but autoregulatory mechanisms caused by differences in CPP cannot be excluded.
开颅手术中的一个关键点是硬脑膜切开，此时高颅内压（ICP）会导致脑组织肿胀。因此，有必要进行关于颅内压、硬脑膜张力程度和脑肿胀程度的对照研究。
在一项开放标签研究中，117例幕上脑肿瘤患者被随机分为丙泊酚 - 芬太尼组（第1组）、异氟烷 - 芬太尼组（第2组）或七氟烷 - 芬太尼麻醉组（第3组）。采用正常至中度低碳酸血症，动脉二氧化碳分压目标水平为30 - 40 mmHg。必要时用静脉麻黄碱（2.5 - 5 mg）稳定平均动脉血压。在过度通气10分钟前后监测硬膜下颅内压、平均动脉血压、脑灌注压（CPP）、动静脉氧差（AVDo2）、颈内静脉血氧饱和度，并计算二氧化碳反应性。此外，神经外科医生评估过度通气前后硬脑膜的张力以及过度通气期间和硬脑膜切开后脑肿胀的程度。
在人口统计学、神经放射学检查、头部位置和颅内压测量时间方面，各组之间未发现差异。在过度通气之前和期间，与第2组和第3组相比，第1组的颅内压显著更低，平均动脉血压和脑灌注压显著更高（P < 0.05）。与第2组相比，第1组在过度通气之前和期间硬脑膜的张力显著更低（P < 0.05），但与第3组无显著差异。在第1组中，硬脑膜切开后脑肿胀明显低于第2组和第3组（P < 0.05）。此外，与第2组和第3组相比，第1组的AVDo显著更高，颈静脉血氧饱和度和二氧化碳反应性显著更低（P < 0.05）。在接受异氟烷和七氟烷麻醉的患者之间，在颅内压、脑灌注压、AVDo、二氧化碳反应性和颈静脉血氧饱和度方面未发现显著差异。
该研究表明，在过度通气之前和期间，与接受异氟烷或七氟烷麻醉的患者相比，丙泊酚麻醉患者的硬膜下颅内压和AVDo2更低，脑灌注压更高。这些发现与丙泊酚组硬脑膜切开后脑肿胀倾向较小有关。接受异氟烷和七氟烷麻醉的患者的二氧化碳反应性显著高于丙泊酚组。各组之间硬膜下颅内压的差异推测是由麻醉剂引起的血管收缩程度差异所致，但不能排除由脑灌注压差异引起的自动调节机制。
