Muizelaar J P, Schröder M L
Division of Neurosurgery, Medical College of Virginia, Richmond 23298-0631.
Can J Neurol Sci. 1994 May;21(2):S6-11.
The relationships between cerebral blood flow (CBF), cerebral metabolism (cerebral metabolic rate of oxygen, CMRO2) and cerebral oxygen extraction (arteriovenous difference of oxygen, AVDO2) are discussed, using the formula CMRO2 = CBF x AVDO2. Metabolic autoregulation, pressure autoregulation and viscosity autoregulation can all be explained by the strong tendency of the brain to keep AVDO2 constant. Monitoring of CBF, CMRO2 or AVDO2 very early after injury is impractical but the available data indicate that cerebral ischemia plays a considerable role at this stage. It can best be avoided by not "treating" arterial hypertension and not using too much hyperventilation, while generous use of mannitol is probably beneficial. Once in the ICU, treatment can most practically be guided by monitoring of jugular bulb venous oxygen saturation. If saturation drops below 50%, the reason for this must be found (high intracranial pressure, blood pressure not high enough, too vigorous hyperventilation, arterial hypoxia, anemia) and must be treated accordingly.
运用公式CMRO2 = CBF × AVDO2，对脑血流量（CBF）、脑代谢（脑氧代谢率，CMRO2）和脑氧摄取（动静脉氧差，AVDO2）之间的关系进行了讨论。代谢自动调节、压力自动调节和黏度自动调节都可以用大脑保持AVDO2恒定的强烈倾向来解释。在损伤后极早期监测CBF、CMRO2或AVDO2并不实际，但现有数据表明脑缺血在这一阶段起着相当重要的作用。通过不“治疗”动脉高血压和不过度使用过度通气，同时大量使用甘露醇可能有益，可以最好地避免这种情况。一旦进入重症监护病房，最实际的治疗可通过监测颈静脉球部血氧饱和度来指导。如果饱和度降至50%以下，必须找出原因（颅内压高、血压不够高、过度通气过猛、动脉缺氧、贫血）并相应地进行治疗。
