[Temporary clipping and cerebral blood flow in patients with cerebral aneurysms].

Regional cerebral blood flow (RCBF) was measured with cerebral aneurysms by the H2-inhalation technique during intraoperative occlusion test in 15 patients. Temporary clipping was followed by a decrease of RCBF below the critical values in most patients. Reperfusion at the removal of a clip from the internal carotid and middle cerebral artery induced a significant hyperemia (298 +/- 55 ml/100 g x min). At the same time, there was no increase in the frequency of postoperative complications due to temporary clipping. This suggests that their development is related to the duration of cerebral ischemia and the state of the blood-brain barrier.

[Temporal arterial clipping and autoregulation of cerebral blood flow at surgery for intracranial aneurysms]. / Vremennoe klipirovanie arterii i autoreguliatsiia mozgovogo krovotoka pri operatsiiakh na tserebral'nykh anevrizmakh.

Preoperative dynamic autoregulatory responses in 20 patients considered as candidates for vessel temporal clipping (TC) and/or arterial hypotension (AH) at surgery for aneurysms were studied by the thigh cuff method. Normal autoregulatory responses at a regulation rate (RoR) of 20.4 +/- 2.8%/s were found in 10 patients > 30 days after subarachnoidal hemorrhage (SH) while RoR was 12.5 +/- 2.5%/s in 10 other patients (30 days, grade III WFNS showed autoregulation impairment. TC and/or AH were proceeded in 17 operated patients. One postoperative death was due to pulmonary embolism. Two poor results with persistent neurological disorders at discharge were associated with TC but in 1 patient. This patient had severe vasospasm and the lowest RoR (9%/s). There were no TC and/or AH postoperative complications in other 14 patients. All of them and 3 other patients with direct aneurysm clipping had a fair outcome.

[Local cerebral blood flow, cortical impedance, cerebral intravascular kinin production during forebrain ischemia and reperfusion in rats]. / Lokal'nyi mozgovoi krovotok, kortikal'nyi impedans, tserebral'noe vnutrisosudistoe kininoobrazovanie pri perednemozgovoi ishemii i reperfuzii u krys.

In the rat model of forebrain ischemia with subsequent reperfusion, an obvious formation of intravascular kinin (IVKF) occurred. The IVKF preceded and coincided in time with the maximum hyperemia and a vasogenic oedema. Local cerebral blood flow (LCBF) increased up to about 187%, at that. In three groups of experimental rats, a correlation was revealed among the ischemia obviousness, IVKF, and development of the brain oedema.

[Oxygen imbalance, blood flow and impedance of the brain in ischemia and reperfusion in rats]. / Narushenie kislorodnogo balansa, krovotok i impedans golovnogo mozga pri ego ishemii i reperfuzii u krys.

In anesthetised rats, during the ischemic period a brain swelling, a decrease in oxygen tension and an increase in the blood doxygenation velocity occurred. In reperfusion, even more obvious disorders of the oxygen balance were revealed suggesting a disorder in the mitochondrial function.

[Local cerebral blood flow and oxygen tension at different stages of surgical intervention in patients with meningiomas of the superior sagittal sinus]. / Lokal'nyi mozgovoi krovotok i napriazhenie kisloroda na razlichnykh étapakh khirurgicheskogo vmeshatel'stva u bol'nykh s meningiomami verkhnego sagittal'nogo sinusa.

The local cerebral blood flow, oxygen tension, local impedance and intragastric pressure were examined in 13 patients with meningiomas of the middle third of the apical sagittal sinus at various stages of surgery including those after ablation of the intrasinus node and its reconstruction. In all the patients the decompressive cranial trepanation showed a blood stream enhancement but on the meningioma side. It is concluded that the degree of disturbances of oxygenative metabolism and blood circulation after the removal and reconstruction of the intrasinus node was dependent on the variant of the sinus injury.

[The intravascular formation of kinins in the brain studied as a new approach to the problem of the re-circulatory complications in the surgical treatment of cerebral ischemia]. / Izuchenie vnutrisosudistogo obrazovaniia kininov v golovnom mozge kak novyi podkhod k probleme retsirkuliatornykh oslozhnenii pri khirurgicheskom lechenii tserebral'noi ischemii.

The improvement of blood supply in the ischemic brain (post-ischemic cerebral reperfusion), which results from surgical treatment, has been shown to improve the neurological status only in the patients who had no lower baseline levels of kininogens (the production of free kinins) in cerebral circulation. Poor surgical outcomes were noted in the cases wherein there was preoperative activated kinin production when blood passed through the brain. Postischemic brain reperfusion was concurrent with kinin production in the cerebral vascular bed in all examinees, but in patients with postoperative complications this process is more active and involves the two kinin-forming systems tissue and plasma ones. It is hypothesized that in the latter case kinins convert from the compensatory to the pathogenetic factor of secondary circulatory disorders. The correlations found may be used to substantiate the use of antikinin therapy and to develop a biochemical test that predicts possible complications after surgical treatment of cerebral circulatory ischemia.

[The rheo-encephalogram during intense reduction of pulse blood-filling of extra- and intracranial tissues]. / Reoéntsefalogramma pri intensivnom umen'shenii pul'sovogo krovenapolneniia vne- ili vnutricherepnykh tkanei.

The changes in the rheoencephalography (REG) values on the side of the occlusion was studied in 18 patients with arterial aneurysms during intravascular manipulations for balloon occlusion of the internal or external carotid artery. Statistically significant changes of the REG amplitude occurred in occlusion of the external carotid artery. Occlusion of the internal carotid artery failed to produce statistically significant changes of the REG amplitude.

[Features of the surgical treatment and immediate postoperative period of patients in the acute period of rupture of arterial aneurysms of the cerebral vessels]. / Osobennosti khirurgicheskogo lechniia i blizhaishego posleoperatsionnogo perioda u bol'nykh v ostrom periode razryva arterial'nykh anevrizm mozgovykh sosudov.

The authors analyse the course of the immediate postoperative period in 27 patients with ruptured arterial aneurysms of the cerebral vessels. The dynamics of the local cerebral blood flow and electric resistance of the brain matter were examined for a comprehensive study of changes in cerebral circulation and metabolism. Intracranial pressure (ventricular and subdural) and mechanical resistance of the brain matter were measured with the M-34 mingograph. Such combination of the examination methods and the findings of neurological examination made it possible to study over time the pathological processes which are interconnected (circulation-metabolism-edema and swelling of the brain) and determine the course of the postoperative period. A dependence between the preoperative condition of patients and the course of the immediate postoperative period was revealed, adequate methods for correction of the pathological reactions are suggested, and the specific features of a complex clinico-physiological control in this category of patients and the informativeness of the different methods of examination are discussed.

[Functional significance of the internal carotid arteries and collateral circulation in cerebral aneurysm surgery]. / Funktsional'noe znachenie vnutrennikh sonnykh arterii i kollateral'noe krovoobrashchenie v khirurgii anevrizm sosudov golovnogo mozga.

The functional significance of the internal carotid artery was appraised in 18 patients with arterial, in 8 with arteriovenous aneurysms and in one patient with atherosclerosis of the cerebral vessels. The appraisal was based on changes in the intracarotid pressure and regional cerebral blood flow (quantitative criteria) in temporary occlusion of the internal carotid artery with a double-lumen balloon catheter and on the change in the patients' clinical condition during temporary or stationary arrest of blood flow through the internal carotid artery that is studied. In large arteriovenous aneurysms, the collateral circulation ensures adequate blood supply to the brain tissue on the side of temporary occlusion of the internal carotid artery. The functional importance of the internal carotid artery in patients with arterial aneurysms points to the possibility of reconstructive operations in aneurysms of the internal carotid artery which are inaccessible for direct intervention. However, it is expedient in every case to make sure that the operation is safe by preoperative appraisal by means of the suggested method.

[Rapid autoregulatory component of cerebral vessels]. / Bystryi komponent autoreguliatsii mozgovykh sosudov.

The changes of cerebral blood flow registered by means of flowmeter in the common carotid artery were investigated during fast raise and drop of arterial blood pressure in acute experiments on anesthetized cats. Both the raise and drop of arterial pressure resulted in fast autoregulatory changes of cerebral blood flow occurring even after resection of cervical sympathetic ganglia. The alpha-adrenergic blockade abolished the fast autoregulatory phase during raise of the arterial pressure. These findings sugget participation of noradrenergic mechanisms in reaction to acute hypertension.

[Clinico-physiologic study of the adequacy of using rheoencephalography to study cerebrovascular circulation in man]. / Kliniko-fiziologicheskoe issledovanie adekvatnosti primeneniia reoéntsefalografii dlia izucheniia mozgovogo krovoobrashcheniia u cheloveka.

Rheoencephaloplethysmography revealed the increase of impedance specific for enhancement of intracranial blood flow after occlusion of both common jugular veins only in the ocular-occipital lead in humans. The intracranial component of rheoencephalography was calculated from the data of interelectrode current distribution in extra- and intracranial tissues. The maximal value of the current through intracranial tissues reached 15 per cent for the ocular-occipital lead.

[Information content of the rheoencephalogram and rheoencephaloplethysmogram for assessing cerebral hemodynamics]. / Informativnost' reoéntsefalogramy i reoéntsefalopletizmogrammy v otsenke mozgovoi gemodinamiki.

In acute experiments in cats, separate measurement of impedance of extra and intracranial tissues and skull bones was carried out by passing 30-150 kHz electrical current. Extra and intracranaial tissue impedances are approximately equal and one order less than that of skull bones which excludes electrical current penetration into the cranial cavity directly through the bone. The changes on electroplethysmograms recorded with extra and intracranial electrodes during simultaneous clipping of both common carotids or external and internal jugular veins were compared. In part of experiments jugular veins were clipped before and after switching off extracranial blood flow. Intracranial impedance changes thus achieved are several times greater than extracranial ones and are not registered in extracranial bitemporal electrode location. The only way to register them without intracranial electrode insertion is by use of ocular-occipital lead. Yet in this case the intracranial component makes only about 30% of the registered signal. This value increases significantly with artifical stabilization of extracranial hemodynamics.