Yamaguchi F, Meyer J S, Sakai F, Yamamoto M
J Neurol Sci. 1979 Dec;44(1):87-94. doi: 10.1016/0022-510x(79)90226-0.
Cerebral vasoconstrictive capacitance was measured during voluntary hyperventilation hypocapnia in 22 healthly normal volunteers aged 21--65 years by serial 133Xe inhalation estimates of rCBF by the initial slope index method of Risberg (ISI2) in the steady state followed by the hypocapnic state. End-tidal PCO2 was monitored by a capnograph. There was significant linear correlation between reduction of PECO2 and the ISI2 values. Significant reduction of cerebral vasoconstrictive response to hypocapnia was found with normal advancing age which is attributed to (1) minor atherosclerosis or loss of elasticity of cerebral vessels with advancing age, (2) the presence of an ischemic threshold during hyperventilation at which CBF tends to stabilize.
通过里斯伯格（Risberg）初始斜率指数法（ISI2），在22名年龄在21至65岁的健康正常志愿者进行自愿性过度通气低碳酸血症期间，通过连续吸入133Xe估计稳态和低碳酸血症状态下的局部脑血流量（rCBF），测量脑血管收缩容量。通过二氧化碳描记器监测呼气末二氧化碳分压（PECO2）。PECO2降低与ISI2值之间存在显著线性相关性。随着年龄正常增长，发现对低碳酸血症的脑血管收缩反应显著降低，这归因于：（1）随着年龄增长，脑动脉出现轻微动脉粥样硬化或血管弹性丧失；（2）过度通气期间存在缺血阈值，在此阈值时脑血流量趋于稳定。
