Ryba M, Johansson K, Cybulska A
Eur Neurol. 1985;24(6):392-7. doi: 10.1159/000115832.
Changes in the lactate and pyruvate levels and lactic dehydrogenase activity in the cerebrospinal fluid were followed in 56 patients anaesthetised for neurosurgery. Mean arterial blood pressure (MAP) was reduced in these patients from about 90 to about 35 mm Hg. This allowed to safely place a clip at a brain artery aneurysm. In spite of deep hypotension, ischaemia described by other authors in such cases was never observed. Changes in lactate and pyruvate concentrations, lactate/pyruvate ratio and lactic dehydrogenase activity justify the conclusion that we were dealing with an undisturbed metabolism of the brain tissue. The levels of metabolic parameters, even when increased in hypotension, fell well within the range of physiological values. Attention is called to the fact that partial oxygen pressure in arterial blood during controlled hypotension was about 100 mm Hg, a value considered as limiting to oxygen metabolic transformation within the central nervous system in deep hypotension. We also suggest a different mechanism of passage of lactates and pyruvates through the blood-brain barrier.
对56例接受神经外科手术麻醉的患者的脑脊液中乳酸、丙酮酸水平及乳酸脱氢酶活性的变化进行了跟踪研究。这些患者的平均动脉血压（MAP）从约90毫米汞柱降至约35毫米汞柱。这使得能够安全地在脑动脉动脉瘤处放置夹子。尽管出现了深度低血压，但从未观察到其他作者描述的此类情况下的缺血现象。乳酸和丙酮酸浓度、乳酸/丙酮酸比值及乳酸脱氢酶活性的变化证明我们所处理的是未受干扰的脑组织代谢。代谢参数水平即使在低血压时升高，也仍处于生理值范围内。需要注意的是，控制性低血压期间动脉血中的氧分压约为100毫米汞柱，这一数值被认为是深度低血压时中枢神经系统内氧代谢转化的极限。我们还提出了乳酸和丙酮酸通过血脑屏障的不同机制。
