Quantitative assessment of cerebral vascular reserve by means of transcranial Doppler ultrasound and rebreathing maneuver: bedside test and mathematical modeling.

摘要: Cerebral vascular reserve was measured by means of the transcranial Doppler (TCD) technique from carbon dioxide (CO2) tests, in healthy individuals and patients with unilateral internal carotid artery (ICA) occlusion. The percentage changes middle cerebral arteries blood flow velocity (VMCA) per mmHg pCO2 variations (reactivity index, RI) were separately computed during hypocapnia hypercapnia, latter obtained a rebreathing maneuver. Clinical data have been compared predictions using an original mathematical model intracranial dynamics, order to search theoretical explanation hemodynamic events observed clinical testing. This analysis has also considered support choice between different CO2 tests for quantitative assessment reactivity. simulations agree showing that side-to-side reactivity differences (Irel) hypercapnia test allow good discrimination poor compensatory capacity. They suggest Irel significantly greater than 30% after can be indicative These preliminary results encourage long-term follow-up TCD “rebreathing test”, selecting may benefit brain revasculatization.