[Arterial and venous brain reactivity in the acute period of brain concussion]

Arterial and venous brain reactivity has been studied in 38 patients in the acute period of brain concussion (BC) and 32 healthy volunteers using transcranial color duplex scanning of brain vessels. The assessment of arterial inflow was conducted for the medial brain artery (MBA) and that of venous outflow - for the basal vein (BV) of Rosenthal. Hyperkinetic and orthostatic probes were used for assessment of cerebrovascular reactivity. BC was not accompanied by marked changes of cerebral resting hemodynamic parameters. The increase of peak blood flow velocity in MBA in the acute period which is characteristic of the brain hyperinfusion was found in 20% of patients and that in BA compensating the disturbed outflow along the surface brain system - in 25% of patients. In normalcy, the brain venous reactivity to hypercapnia was higher than arterial one and that to orthostasis corresponded to the intensity of arterial changes. The lack of quantitative differences in the reaction of arterial and venous blood flow to hypercapnia and the predominance of venous reactivity value in orthostasis in patients with BC suggest the disturbance of venous tone regulation in these patients.