[Measurement of arteriovenous oxygen difference in the monitoring of patients with subarachnoid hemorrhage due to cerebral aneurysm]. / Medida da diferença artério-venosa de oxigênio na monitorização de pacientes com hemorragia subaracnóidea por aneurisma cerebral.

The arterious venous oxygen difference (AVDO2) due to the close relationship with cerebral metabolic rate of oxygen and cerebral blood flow shows metabolic alterations that occur in some pathological situations in the brain including subarachnoid haemorrhage. The AVDO2 was calculated by the Fick equation and the results evaluated by the Glasgow outcome scale. Measurements of arteriojugular oxygen difference were carried out in 30 patients with subarachnoid haemorrhage due to rupture of intracranial aneurysms, as an attempt to monitor the relationship between changes in AVDO2, clinical picture, and evolution of the patients. The subarachnoid haemorrhage was diagnosed by CT scan in 17 patients and by lumbar punction in 13 and the diagnosis of arterial vasospasm was carried out by clinical evaluation and confirmed by four vessels angiogram in only eight patients. Eighteen patients were admitted with Hunt & Hess (H&H) I/II, seven with H&H III and five with H&H IV/V. Nineteen patients had AVDO2 normal and this group had three deaths; five patients had AVDO2 continuously low with three deaths; and six patients had AVDO2 continuously high with two deaths. The patients with normal AVDO2 had better prognosis and clinical evolution than the patients with abnormal values of AVDO2. In conclusion, AVDO2 measurements could not be correlated with the diagnosis of vasospasm, but was useful in the early identification of metabolic changes that occur after subarachnoid haemorrhage and could be used as an supplementary monitoring in the clinical evaluation of patients with this pathology.