SECONDARY SYSTEMIC INSULTS TO THE BRAIN

The prevention and treatment of secondary insults to the brain of syst emic origin in severely head injured patients remain of utmost importa nce. Head injury remains the leading cause of traumatic death, being r esponsible for 50-60 % of fatalities. Head-injured patients not only s uffer from the primary injury at the time of trauma, but also from the secondary, largely ischaemic, brain damage that occurs later. Some of these insults are of extracranial origin (or systemic), such as arter ial hypotension, hypoxaemia, hypercarbia and anaemia. Their impact on mortality and morbidity is extremely high and requires greater efforts in improving the care of head-injured patients. Systemic insults occu r either before the patient reaches hospital or during interfacilty tr ansfer or, in a surprisingly large number of cases, within hospital du ring emergency procedures, intrahospital transport or during their sta y in intensive care units. Hypoxaemia, although quite easy to treat, i s still common. This calls for better and earlier protection of the ai rway, more systematic administration of oxygen to trauma patients and wider use of pulse oximetry. Arterial hypotension has even more dramat ic consequences in severe head injury. Recent studies indicate that sh ort episodes of hypotension may induce severe brain ischaemia, that wi ll be present even after complete systemic haemodynamic restoration. T he treatment of hypotensive episodes should be immediate and agressive . In some circumstances, restoration of an adequate cerebral perfusion pressure may not be obtained sufficiently rapidly with fluids alone a nd may require early use of vasopressors. Optimal haemodynamic resusci tation of the trauma patient with haemorrhagic hypotension and severe head injury remains a special challenge. Hypertonic saline, with or wi thout additional colloids, could be beneficial, especially in the preh ospital setting. Numerous experimental and a few recent clinical studi es are promising but need further clinical investigations.