Influence of the blood gas transport system on brain millivolt scale direct current potentials in patients with vascular encephalopathy

Abstract

Introduction. Millivolt Scale direct current potentials (DCP) registered from human scalp differ from other types of estimated electrical activity by closer association with cerebral energetic processes. Intense energy metabolism in the brain increases the difference between acidic products concentrations on both sides of the blood brain barrier which is reflected by higher DCP. Oxygen consumption of is one of the most important components of cerebral energy metabolism. Delivery of oxygen to neuron depends on the characteristics of blood oxygen transport system and cerebral blood flow. Objective. To test the hypothesis that brain DCP depends of the blood oxygen transport system characteristics and cerebral blood flow. Materials and methods. Erythrocytes number, erythrocyte sedimentation rate, hemoglobin and fibrinogen levels in blood were examined in135 patients with vascular encephalopathy (VE) Blood flow velocity in major head arteries was estimated using Doppler ultrasound. Associations between blood characteristics and blood flow velocity and the brain DCP, recorded in frontal, central, occipital areas along the midline and in both temporal areas, were determined. Results. Associations between brain DCP and the blood oxygen transport system characteristics as well as the cerebral blood flow velocity were discovered in patients with VE. Averaged values of DCP in all examined areas were significantly different in groups with high and low hemoglobin levels (Fisher coefficient (F) = 5.5; p = 0.02) and corpuscular hemoglobin levels (F = 7.0; p 0.01). The blood flow velocity in the internal carotid artery correlated with DCP in central areas of the head (r = 0.37; p = 0.003). The values of averaged DCP (over all areas) negatively correlated with blood sedimentation rate (r = -0.31; p= 0.002) and fibrinogen levels (r = -0.37; p 0.001). Conclusions. Evidences of the association between DCP and the brain oxygen transport system were obtained. Higher level of hemoglobin and a higher rate of cerebral blood flow promote more intensive rates of brain oxygen consumption. Discovered correlations between the blood oxygen transport system characteristics, cerebral blood flow and brain DCP confirm the potential benefit of using the millivolt range slow brain electrical activity measurement to characterize cerebral energy metabolism in clinical and experimental setting.

Keywords

• blood gas transport system
• cerebral blood flow
• millivolt scale of brain direct potentials
• vascular encephalopathy