[The behavior of intracranial pressure and intracranial compliance in nifedipine-induced hypotension].

The influence of nifedipine induced hypotension on intracranial pressure (ICP) and intracranial compliance (ICC) was investigated in dogs without (group I, n = 8) and with (group II, n = 8) intracranial hypertension. ICP in group II was raised by gradual inflation of an epidurally placed balloon catheter. A volume-pressure-response curve (VPR) was established before and during the administration of nifedipine. In group II dogs angiotensin was infused before and during infusion of nifedipine in a dose sufficient to raise mean arterial pressure (MAP) by 30-40 mm Hg. An infusion of nifedipine (2 micrograms X kg-1 X min-1) subsequent to a bolus injection of nifedipine (10 micrograms X kg-1) resulted in a significant and sustained decrease in MAP (p less than 0.05) by 25% and 35% resp. due to a significant reduction in total peripheral resistance (p less than 0.05). ICP increased from 8.7 +/- 3.0 mm Hg to a maximum of 12.5 +/- 5.2 mm Hg in group I animals (p less than 0.05) and from 19.8 +/- 2.6 mm Hg to 24.8 +/- 7.2 mm Hg not significantly in group II dogs. The pressure-volume-index revealed a slight reduction of ICC in group I and a slight increase of ICC in group II resp. during nifedipine as compared to before nifedipine. When angiotensin was being administered in group II dogs before nifedipine was given, MAP increased by 40 +/- 5.8 mm Hg while ICP did not change significantly (+2 +/- 2.4 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)