| Summary: | 32 patients admitted to the intensive care unit with either traumatic brain injury or spontaneous subarachnoid haemorrhage were studied. A comparison of two monitors (Critikon 2020 and Invos 3100) used to measure cerebral oxygenation by means of near infra-red spectroscopy in the intensive care unit was carried out using volunteer subjects. The effect of induced arterial hypertension on cerebral blood flow and metabolism was studied in 32 patients with acute brain injury in the intensive care unit. We found significant intracranial production of interleukin-6 after injury, and raised systemic concentrations of intercellular adhesion molecule-1 (ICAM-1) , NSE and dS-100. These systemic changes were all significantly related to outcome. Concentrations of ICAM-1 were negatively correlated with Glasgow Coma Score, but were not influenced by the presence of extracranial injuries. Systemic concentrations of L-selectin were significantly reduced after injury. The Critikon monitor failed to provide any reading in 44% of subjects, while the Invos failed in 20%. Differences between oxygen saturation readings from each monitor were related to the average saturation. Cerebral blood flow was adequate in all patients in the induced hypertension study. 51% of subjects were treated with noradrenaline to keep cerebral perfusion pressure above 70 mmHg. 36% of subjects with traumatic brain injury developed cerebral hyperaemia, which was unrelated to noradrenaline use. The highly significant relationship between systemic ICAM-1 and outcome suggests that antagonism of its effects may form part of future drug therapies for brain injury. The development of new monitoring technologies must result in monitors which function reliably in the intensive care unit, or their use will not be considered worthwhile. Induced hypertension is a treatment method which may reduce the likelihood of cerebral ischemia without resulting in inappropriate cerebral hyperaemia. Therapeutic measures which monitor and assist in cerebral oxygen delivery, and reduce inflammatory damage may improve outcome after brain injury.
|
|---|
