Intracranial pressure changes induced by sodium nitroprusside in patients with intracranial mass lesions.

Because of the ability of sodium nitroprusside (SNP) to dilate cerebral blood vessels, intracranial pressure (ICP) should increase with its use. In patients with vascular intracranial tumors following SNP (0.01%) infusion, ICP increased from 14.58 +/- 1.85 to 27.61 +/- 3.33 torr (p greater than 0.0005) and cerebral perfusion pressure decreased from 89.32 +/- 3.5 to 43.23 +/- 4.60 torr (p less than 0.0005) when the mean arterial pressure had reduced by 33%. These results suggest that SNP not be used in patients with raised ICP unless previous measures have been taken to improve intracranial compliance.