The effects of normobaric hyperoxia on oxidative stress and factors of endogenous vascular regulation in patients who suffered from non-traumatic subarachnoid hemorrhages and remained in critical condition.

The development of cerebral vasoconstriction in subarachnoid hemorrhage (SAH) induced by the rupture of an aneurism of brain vessels impairs cerebral circulation. Treatment with normobaric hyperoxia may be used as an effective approach to oxygen delivery to the injured brain tissue. The purpose of the present study was to evaluate the effects of normobaric hyperoxia on oxidative stress and factors of endogenous vascular regulation in eight patients who suffered from non-traumatic SAH and remained in critical condition. The intensity of oxidative stress was assayed by measuring malonic dialdehyde and the total antioxidant activity in the blood serum. Endothelium functions were evaluated using the content of the stable metabolites of nitric oxide and the activity of angiotensin-converting enzyme in the blood serum. The data from eight patients who suffered from non-traumatic SAH showed an enhancement of oxidative stress, which influenced the functions of the vascular endothelium and resulted in an imbalance in the endogenous regulation of vascular tone. Treatment with normobaric hyperoxia was not associated with intensification of free-radical processes in patients who suffered from non-traumatic SAH and did not influence intracranial and arterial pressure. [ABSTRACT FROM AUTHOR]