Effect of anaesthetic agents on the ionic composition of cerebrospinal fluid following total cerebral ischaemia.

Total cerebral ischaemia in rats caused a marked increase in the cisternal CSF potassium concentration but little change in CSF sodium or chloride concentration. The anaesthetic techniques studied (pentobarbitone, halothane/oxygen and nitrous oxide/oxygen/relaxant) did not effect the potassium increase following cerebral ischaemia. We conclude that the mechanism of barbiturate protection following cerebral ischaemia is different from that of hypothermia.