Differential approach to the application of hyperventilation in acute period of severe brain injury in relation to cerebral circulation

Seventeen patients with severe brain injury (Glasgow-8 Coma Scale 3-8 scores) complicated by traumatic subarachnoidal hemorrhage and severe cerebral hemodynamic disorders (hyperemia, vasospasm) were examined. Hyperventilation was performed in different phases of cerebral circulation under multiparametrical monitoring (intracranial pressure, cerebral perfusion pressure, jugular oximetry, Doppler study using the carotid compression test). The use of hyperventilation to eliminate intracranial hypertension in victims with brain hyperemia was shown to make cerebral circulation consistent with brain tissue oxygen demands and to improve the autoregulatory reserve of cerebral vessels. The application of hyperventilation to eliminate intracranial hypertension in vasospasm leads to a temporary reduction in intracranial pressure, but simultaneously causes cerebral circulatory changes that do not correspond to cerebral oxygen demands, as well as lowered cerebral perfusion pressure, which increases a risk for ischemic brain tissue lesion. This requires a strict rationale for the use of hyperventilation and for multiparametrical monitoring of cerebral functions, which includes jugular oximetry, Doppler transcranial study, and measurement of intracranial pressure throughout the hyperventilation period in order to prevent secondary brain lesion.