Intracranial pressure during nifedipine-induced hypotension.
The effect of nifedipine-induced hypotension on intracranial pressure (ICP) was investigated in cats with normal and artificially increased ICP. Eleven cats were anesthetized with intraperitoneal pentobarbital (25 mg/kg), intubated, and ventilated with nitrous oxide in oxygen. Mean arterial pressure (MAP), heart rate (HR), and mean pulmonary artery pressure (PAP) were continuously recorded. A double 19-gauge needle was inserted into the cisterna magna; ICP was continuously monitored from one needle and the other was used to increase and maintain ICP at 27 +/- 4 mm Hg by infusion of pH-adjusted Ringer's lactate solution. After control measurements were taken, nifedipine was given intravenously in each cat when ICP was normal and increased. Infusion of 96 +/- 12 micrograms (SEM) nifedipine (approximately equal to 33 micrograms/kg) reduced MAP 35-45% for 2.5 +/- 0.8 min when ICP was normal, and for 2.0 +/- 0.6 min when ICP had been increased. When initial ICP was normal, nifedipine-induced hypotension produced a small (2.2 mm Hg) but statistically significant increase in ICP and decrease in cerebral perfusion pressure (P less than 0.01). When ICP was initially elevated, nifedipine-induced hypotension produced a larger increase in ICP (5 +/- 1 mm Hg) and a proportionately larger decrease in cerebral perfusion pressure (P less than 0.01).
D000818:Animals; D002415:Cats; D006439:Hemodynamics / Q000187:drug effects; D007023:Hypotension, Controlled / Q000009:adverse effects*; D007263:Infusions, Parenteral; D007427:Intracranial Pressure / Q000187:drug effects*; D009543:Nifedipine / Q000008:administration & dosage / Q000633:toxicity*; D011559:Pseudotumor Cerebri / Q000503:physiopathology
D009543:Nifedipine