Influences of phasic changes in systemic blood pressure on intracranial pressure.

In acute experiments on lambs, the effects of short-lasting induced modifications in arterial and venous systemic blood pressure on intracranial pressure have been studied. Haemodynamic changes have been provoked by increasing the cardiac venous return, by increasing or decreasing the arterial resistance and by stimulating the vagus nerve. Intracranial pressure modifications have been demonstrated to depend essentially on arterial influences. A direct venous influence is apparent only when the central venous pressure is increased, as occurs in the case of increased venous cardiac return.