MONITORING OF JUGULAR VENOUS OXYGEN-SATURATION IN COMATOSE PATIENTS WITH SUBARACHNOID HEMORRHAGE AND INTRACEREBRAL HEMATOMAS

To prevent secondary cerebral ischaemia in comatose patients it would be of great importance to assess cerebral blood flow. Recently monitor ing of the jugular venous oxygen saturation (SJVO2) has been shown to continuously evaluate cerebral oxygenation and to estimate cerebral bl ood flow. While most of these studies have dealt with severely head in jured patients, we investigated cerebral oxygenation in 50 comatose pa tients due to an intracerebral haematoma (n = 14), subarachnoid haemor rhage (n = 12) and severe head injury (n = 24). In these groups of pat ients, the reaction of SJVO2 to hyperventilation and to lowering of bl ood pressure was studied. Moderate hyperventilation from 35 to 28 mmHg resulted in a significant decrease of SJVO2 in all groups. A critical SJVO, between 50 and 55% was found in one half of the patients studie d, a pathological SJVO2 below 50% was seen in 23% of the cases. Loweri ng of arterial blood pressure within the limits of autoregulation resu lted in decreases of SJVO2 in patients with intracerebral haematomas o nly. 55% of these patients showed signs of insufficient cerebral oxyge nation. Furthermore the frequency of spontaneous desaturation episodes was studied retrospectively and comparison made between the different groups. These episodes were found more frequently in patients with in tracerebral haematomas compared to patients with severe head injury. I n conclusion, monitoring of jugular venous oxygen saturation is a valu able tool for detecting and treating insufficient cerebral oxygenation in comatose patients following intracerebral haemorrhage, subarachnoi d haemorrhage and severe head injury.