Management of Intracranial Hypertension in Head Injury: Matching Treatment with Cause
an increase in cerebral blood volume best treated by hyperventilation and hypnotic drugs,
an increase in brain water content best treated by osmotherapy and
increased CSF outflow resistance best treated by CSF drainage. This last cause seldom predominates in head injury.
To determine whether it is possible to identify the best therapy in individual head injured patients, we are comparing osmotherapy (mannitol) and hypnotic drugs (thiopentone and gamma-hydroxybutyrate) in selected patients with severe head injury where it is possible to maintain standard conditions of ventilation and stable blood pressure and to measure ICP, CPP, brain electrical activity, PR ratio of the ICP wave form and cerebral AvDO2 before and during each of the two forms of therapy. Effective therapy means that ICP has been reduced to 20 mm Hg with preservation or improvement in CPP.
17 patients have been studied so far and 4 groups identified. Osmotherapy was superior to hypnotic in 5 cases, hypnotic superior to mannitol in 3 cases, both were effective in 5 cases and neither effective in 4 cases. Patients in whom hypnotics were superior tended to be younger, with diffuse rather than focal brain injury, had the highest levels of brain electrical activity prior to treatment and a higher PR ratio. During successful therapy AvDO2 decreased and patients made a good recovery suggesting that in the patients who responded best to hypnotic drugs the primary brain damage was not severe.
KeywordsHead injury intracranial hypertension cerebral monitoring osmotherapy and hypnotics
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