Meixensberger J
Department of Neurosurgery, University of Würzburg, Federal Republic of Germany.
Acta Neurochir Suppl (Wien). 1993;59:28-33. doi: 10.1007/978-3-7091-9302-0_5.
The possibility of measuring cerebral blood flow by mobile bedside units with the intravenous 133-Xenon technique increased the interest to monitor haemodynamic changes after head injury and subarachnoid haemorrhage in intensive care. Time course of resting CBF after trauma is variable (reduced CBF, hyperemia) and there is no strong correlation to clinical outcome. Additional studies of CBF/CO2 reactivity show normal and impaired CO2 response in the acute stage after trauma (day 1-8). A permanently impaired CO2 reactivity correlates with severe brain damage and bad outcome (GOS 1,2). A normal or improving CO2 reactivity indicates a favourable outcome (GOS 3-5). There was no significant correlation between CBF and ICP, nor between CBF and CPP. A CPP of more than 70 mmHg did not guarantee a sufficient CBF in every case indicating the variability of the limits of autoregulation. As therapeutic hyperventilation may lead to ischemia, mannitol was preferred to reduce ICP and increased low CBF to normal values. This fact should be considered in the treatment of patients with low CBF and normal CO2 reactivity. Delayed ischemic neurological deficits ("vasospasm") are well-known as significant complications of the clinical course following SAH. Immediately postoperatively performed CBF measurements enable to detect ischemia and allow to start early antiischemic therapy. During "vasospasm" CBF showed a better correlation to the neurological status than blood flow velocity in the basal arteries measured by transcranial doppler sonography. Furthermore hyperemia after SAH could only be verified by CBF measurements.
采用静脉注射133-氙技术的床边移动设备测量脑血流量的可能性，增加了人们对在重症监护中监测头部受伤和蛛网膜下腔出血后血流动力学变化的兴趣。创伤后静息脑血流量的时间进程是可变的（脑血流量减少、充血），且与临床结果没有很强的相关性。对脑血流量/二氧化碳反应性的进一步研究表明，创伤后的急性期（第1 - 8天）二氧化碳反应正常和受损。永久性的二氧化碳反应受损与严重脑损伤和不良预后（格拉斯哥预后评分1、2级）相关。正常或改善的二氧化碳反应性表明预后良好（格拉斯哥预后评分3 - 5级）。脑血流量与颅内压之间、脑血流量与脑灌注压之间均无显著相关性。脑灌注压超过70 mmHg并不能在每种情况下都保证足够的脑血流量，这表明了自动调节限度的变异性。由于治疗性过度通气可能导致缺血，甘露醇更适合用于降低颅内压并将降低的脑血流量提高到正常水平。在治疗脑血流量低且二氧化碳反应正常的患者时应考虑这一事实。延迟性缺血性神经功能缺损（“血管痉挛”）是蛛网膜下腔出血临床病程中众所周知的重要并发症。术后立即进行脑血流量测量能够检测缺血并允许开始早期抗缺血治疗。在“血管痉挛”期间，与经颅多普勒超声测量的基底动脉血流速度相比，脑血流量与神经状态的相关性更好。此外，蛛网膜下腔出血后的充血只能通过脑血流量测量来证实。
