[Middle cerebral artery (MCA) blood flow velocity and intracranial pressure (ICP) were recorded in 42 patients suffering from raised ICP. A major (ICP25 mmHg) or moderate (251CP15 mmHg) degree of intracranial hypertension was reduced by means of either continuous or intermittent CSF drainage. Measurements of MCA blood flow velocity were carried out with transcranial Doppler sonography (TCD). Three types of reactions were observed with regard to cerebral blood flow velocity (CBFV) changes in response to CSF drainage. Patients in Group 1 demonstrated pressure passive CBFV changes throughout the observed cerebral perfusion pressure (PP) range. In Group 2, cerebrospinal fluid (CSF) drainage brought about a transitory increase in CBFV for a few minutes. In Group 3, the reduction of ICP to the normal level did not influence CBFV at all. The pulsatility index (PI) of the cerebrovascular reserve capacity (CVR), which was highest in Group 1, changed in contrast with the CBFV changes in Groups 1 and 2. The pressure-passive velocity pattern (in Group 1) suggests that the blood vessels were at nearly maximum dilatation and were perhaps failing to constrict properly in response to increased PP. As recovery proceeded (Group 2), the mechanism became effective, thereby reestablishing autoregulation. Whereas clinical signs and computed tomography reveal only the trend of the ICP, TCD provides the possibility of a semi-quantitative evaluation of ICP changes and seems especially promising in the rapid assessment of the efficacy of treatment aimed at ICP reduction.]

[Peptidergic fibres innervating human embryonic and adult cerebral blood vessels were screened for calcitonine gene-related peptide, neuropeptide-Y and substance-P immunopositive fibres, the mediaadventitia border displayed a network-like fibre arrange ment. There was no significant difference either in the distribution of the individual peptidergic fibres or in the age-dependent appearance of peptidergic networks. On the basis of these results it seems to be unlikely that the different clinical course of juvenile and adult subarachnoid haemorrhages could be the result of an age specific difference of peptidergic fibre distribution influencing the neurogenic mecha nisms of cerebral autoregulation.]

[In 22 patients with subarachnoid hemorrhage secondary to ruptured intracranial aneurysms serial neurological evaluations, transcranial Doppler examinations and computer tomographic scans were performed. Transcranial Doppler flow velocities were significantly elevated for the group with vasospasm on posthemorrhage day 2. The maximum blood flow velocities were recorded between days 9 and 18, with normalization occurring within the following 3 weeks. Increase in velocity preceded clinical symptoms and could therefore be used as a prognostic factor for the management of patients with subarachnoid hemorrhage. The data also indicated that the extent and location of blood in the subarachnoid space determine the severity and location of vasospasm.]

[Background - Management of cerebral perfusion pressure is an important element of the treatment of traumatic brain injury. Vasopressors are accepted as a method of choice to increase mean arterial blood pressure and thus cerebral perfusion pressure in the face of rising intracranial pressure. There are, however, some unresolved issues and potential risks to this therapy. Matherial and methods - This study therefore examines the effects of dopamine on physiological changes as well as on brain edema and water content that can be readily assessed by MRI/MRS in 1. a rodent model of rapidly rising intracranial pressure, caused by diffuse injury with secondary insult and 2. a model of cortical contusion. Results - Dopamine was capable of restoring cerebral perfusion pressure in the model of rapidly rising intracranial pressure. However, this was associated with only a partial restoration of cerebral blood flow. In the brain tissue two profiles of change in the apparent diffusion coefficient of water (ADCw) were seen; one in which ADCw recovered to baseline, and one in which ADCw remained persistently low. Despite that dopamine did not alter these profiles, MRI-assessed tissue water content was increased four hours after injury and dopamine increased cerebral water content in both subgroups of injury, especially in the subgroup with a persistently low ADCw (p<0,01). In the contusion group dopamine significantly worsened the edema both in the injured and in the contralateral area of hippocampus and temporal cortex even though the ADCw values did not change, except for the contralateral hippocampus, where both water content and ADCw values rose with treatment, suggesting extracellular accumulation of water. Conclusion - The results suggest that dopamine has a double effect - while it temporarily and partially restores cerebral blood perfusion, at the same time it induces an increase in brain swelling and thus an increase in intracranial pressure in some cases. It is possible that in a subgroup of patients vasopressor treatment leads to an opposite effect several hours later. Vasopressor therapy in the clinical setting therefore should be cautiously applied.]

[Background and purpose - The frequent orthostatic intolerance in Parkinson’s disease could be the consequence of cardiovascular autonomic failure and/or a damaged cerebral autoregulation (AR). To clarify this question the regulation of cerebral circulation was investigated by polygraphic method. Methods - On a tilt table simultaneous and continuous registrations were made of MCA velocity (VMCA) by transcranial Doppler, arterial blood pressure by non-invasive method, and end-tidal CO2, in supine and in tilted positions of 10°, 30°, 70° grades. The cerebral autoregulation was characterized by the slope of the curve of the arterial blood pressure at the level of the Willis-circle (BPW, as MCA perfusion pressure) plotted against the MCA velocity, achieved by linear regression (y=ax+b function, a=AR, or index of autoregulation). Patients - The data of 17 parkinsonian patients (PP) and eight age-matched controls (C) were analyzed. Results - The decrease of blood pressure in parkinsonian patients was significantly lower than in the controls when supine position was restored from 70° (ΔABP 70°-0°PP= -3.1±7.5 Hgmm; ΔABP 70°-0C°=-11.1±7.3 Hgmm; p<0.05), which suggests a damage to the sympathetic cardiovascular system. A disturbance of the cerebral autoregulation in patients was suggested by a progressively decreasing MCA average velocity (VMCA) during graded tilt, which was significiant at 70° (ΔVACM=9.8±8.82% cms-1; pCPP <0,05), and by a higher slope of pressure-velocity curve (ARC=0.143±0.125% cms-1/Hgmm; ARPP=0.38±0.25% cms-1/Hgmm; pC-PP<0.05). Conclusions - The results show that the cerebral blood flow of patients is more dependent on perfusion pressure compared to healthy controls. The disturbance of the sympathetic cardiovascular system and of cerebral autoregulation could be the consequence of a damage to the postganglionic structures in Parkinson’s disease. These results could explain the frequent orthostatic intolerance of patients even with normal blood pressure.]