Dynamics of the blood pressure changes in sodium nitroprusside induced controlled arterial hypotension in neurosurgery.

Dynamics of the arterial blood pressure changes under the influence of intravenous infusion of sodium nitroprusside (SN) were studied in 12 patients operated on for intracranial aneurysms. Adequate measures were undertaken to avoid blood pressure (BP) changes due to the anaesthetic procedure itself. It was found that the speed of BP lowering corresponded to the rate of infusion, and could easily reach 10 mm Hg/min. After stopping the infusion, the BP recovery rate averaged a mean speed of 8.5 mm Hg/min, varying from 3.8 to 12 mm Hg/min. High speeds of BP lowering and recovery achieved with the use of SN are the main advantages of this hypotensive agent in neurosurgical procedures.