Episodes of Cerebral Maloxygenation in Comatose Patients
Prevention of secondary cerebral ischemia is a main objective in the treatment of comatose patients. In spite of considerable progress made by monitoring of intracranial pressure (ICP), arterial blood pressure, and cerebral perfusion pressure (CPP), episodes of cerebral maloxygenation still occur [3, 8, 11–13]. Measurement of cerebral blood flow would add valuable information, but available methods are not suitable for bedside use and yield only intermittent values. Monitoring of venous oxygen saturation in the jugular bulb allows continuous assessment of cerebral oxygenation [1, 4, 6, 13]. Normal values of jugular venous oxygen saturation (SJVO2) range between 55% and 75%. A SJVO2 of less than 55% is considered critical and one of 50% or below indicates an insufficient cerebral oxygenation. This coincides with an increase in the arteriovenous lactate difference. This study investigated the occurrence and frequency of episodes of desaturation in comatose patients and analyzed possible causes of cerebral maloxygenation. Additionally, pCO2 and CPP were systematically varied in some patients to study the effects on SJVO2.
KeywordsCerebral Perfusion Pressure Severe Head Injury Jugular Bulb Acute Brain Injury Comatose Patient
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