Hashimoto K, Kikuchi H, Ishikawa M, Kinuta Y, Akiyama Y
Department of Neurosurgery, Faculty of Medicine, Kyoto University, Japan.
No To Shinkei. 1990 Feb;42(2):153-8.
The cerebral microcirculation under increased intracranial pressure was evaluated by using reflectance photometric method. The values of tissue hemoglobin (IHb) and its oxygen saturation (ISO2) detected by this method were evaluated in cat brain tissue. The correlation between IHb and content of cortical hemoglobin subunits in vitro was high. High correlation between ISO2 and blood oxygen saturation in superior sagittal sinus was also noted in hypoxic hypoxia. Thus, the reflectance photometric method was revealed to be applicable for evaluation of regional hemoglobin content and oxygen saturation. Using this method the cerebral microcirculation was studied in an increased intracranial pressure model produced by injection of artificial CSF into the cisterna magna in cats. Regional cortical cerebral blood flow (CBF) was measured simultaneously by thermal diffusion method. During decrease of perfusion pressure down to 40 mmHg with preservation of CBF, compensatory increase of IHb was not observed, but IHb rather gradually decreased. The decrease of IHb would be due collapse of capacitance vessels by increased intracranial pressure. Cerebral ISO2 was stable as well as CBF. Less than 40 mmHg of perfusion pressure, ISO2 started to decrease in association with CBF and IHb. Since ISO2 seems to be closely related to the tissue oxygen extraction the change of ISO2 reflect the CBF and tissue cerebral oxygen metabolism. Present study suggest the evaluations of IHb and ISO2 were an useful monitoring indexes in various cerebral disorders.
采用反射光度法评估颅内压升高时的脑微循环。用该方法检测猫脑组织中的组织血红蛋白（IHb）值及其氧饱和度（ISO2）。体外实验中，IHb与皮质血红蛋白亚基含量之间具有高度相关性。在低氧性缺氧状态下，还发现ISO2与上矢状窦血氧饱和度之间具有高度相关性。因此，反射光度法被证明适用于评估局部血红蛋白含量和氧饱和度。利用该方法，在通过向猫的枕大池注射人工脑脊液建立的颅内压升高模型中研究脑微循环。同时采用热扩散法测量局部皮质脑血流量（CBF）。在灌注压降至40 mmHg且CBF保持不变的过程中，未观察到IHb的代偿性增加，反而IHb逐渐降低。IHb降低可能是由于颅内压升高导致容量血管塌陷所致。脑ISO2和CBF一样保持稳定。灌注压低于40 mmHg时，ISO2开始随CBF和IHb降低。由于ISO2似乎与组织氧摄取密切相关，因此ISO2的变化反映了CBF和脑组织氧代谢情况。本研究表明，IHb和ISO2的评估是各种脑部疾病中有用的监测指标。
