ALL OF US have observed patients with apparent severe brain damage secondary to anoxia. These patients frequently have a transient period of hypertension, and then many go into shock. Nevertheless some survive such an episode with an apparently normal recovery as reported by Sadove et al.1 One wonders whether the lowered blood pressure is caused by cardiovascular collapse which is primary or collapse which is secondary to central nervous system damage.
Using dogs, we have attempted to learn more about these mechanisms by utilizing some of the techniques employed by Harvey Cushing as well as more modern methods. Specifically, we have used the technique of increasing the cerebrospinal fluid pressure to produce cessation of the cerebral blood flow. Cushing2 demonstrated the rise in blood pressure that accompanies the rise in cerebrospinal pressure. He also demonstrated, by means of transparent fluid-tight windows maintained in the skulls of dogs,