Cerebral Blood Flow Autoregulation in Acute Intracranial Hypertension (original) (raw)

1994, Journal of Cerebral Blood Flow & Metabolism

The present series of experiments was carried out to investigate CBP autoregulation during fixed levels of acute increased intracranial pressure (ICP). Three groups of six rats each, one with normal ICP (8 mm Hg), one with moderately increased ICP (30 mm Hg), and one with severely increased ICP (50 mm Hg), were investi gated. ICP was maintained by continuous infusion of lac tated Ringer solution into the cisterna magna. Cerebral perfusion pressure (CPP), calculated as mean arterial blood pressure -ICP, was increased by intravenously infused norepinephrine and decreased by controlled bleeding. In all groups the corresponding autoregulation curve included a plateau where CBP was independent of Within wide variations in cerebral perfusion pres sure (CPP), cerebral autoregulation ensures a steady blood supply to the brain by adjusting the cerebrovascular resistarke (CVR). This process is an active alteration of the caliber of the resistance vessels in the brain (Paulson et aI., 1990). How the fine mechanism of autoregulation is controlled is still not completely understood, but it has been shown that CBF is kept constant within the range of autoregulation during altered mean arterial blood pressure (MABP), intracranial pressure (ICP), and jugular venous pressure (JVP) (Miller et aI., 1971(Miller et aI., / 1972 Johnston et aI.