Cerebral blood flow in the acute phase after head injury. Part 1: Correlation to age of the patients, clinical outcome and localisation of the injured region.

In 40 comatose patients with severe head injury, a total of 114rCBF studies were performed with the intraarterial 133xenon washout technique over the most severely injured hemisphere. All patients were subjected to respirator treatment, and mildly sedated with diazepam, chlorpromazine or meperidine. The average values of the regional flow were corrected for changes in PaCO2 by simultaneous measurements of CO2 reactivity. A PaCO2 value of 30 mmHg (4 kPa) was chosen as the reference value. The results indicate that hyperaemia following head injury is a common phenomenon, especially in young victims with supratentorial cortical lesions. The hyperaemic phase can last from some days to several weeks and is of no prognostic significance. In elderly patients with supratentorial cortical lesions, and in patients with mainly brain-stem lesions or diffuse brain lesions a persistent low flow state was observed in the acute phase (first 1-3 days after the injury). This low flow state was also observed 1-2 weeks after the injury if loss of consciousness persisted, but it was of no prognostic significance, as CBF values between 15 and 20 ml/100 g/min were associated with a good recovery.