SEVOFLURANE IMPROVES NEUROLOGICAL OUTCOME AFTER INCOMPLETE CEREBRAL-ISCHEMIA IN RATS

We have studied the effects of sevoflurane on neurological outcome in a rat model of incomplete cerebral ischaemia. After institutional appr oval, 30 non-fasted male Sprague-Dawley rats (455-555 g) were anaesthe tized, the trachea intubated and the lungs ventilated mechanically wit h isoflurane and 30% oxygen in air. Catheters were inserted into the r ight femoral artery, both femoral veins and into the right jugular vei n for measurement of arterial pressure, drug administration and blood sampling. At completion of surgery, isoflurane was discontinued and th e rats were allowed an equilibration period of 30 min according to the following regimens: group 1 (n = 10) received 70% nitrous oxide in ox ygen and fentanyl (bolus 10 mu g kg(-1) i.v.; infusion 25 mu g kg(-1) h(-1)); group 2 (n = 10) received 1.98 vol% sevoflurane in oxygen and air (FIO2 0.3); group 3 (n = 10) received 1.98 vol% sevoflurane in oxy gen and air (FIO2 0.3) and 40% glucose (6 ml kg(-1) i.p.) 30 min befor e ischaemia. Ischaemia was produced by combined unilateral common caro tid artery ligation and haemorrhagic hypotension to 35 mm Hg for 30 mi n. Temperature, arterial blood-gas variables and arterial pH were main tained within the physiological range. Plasma glucose concentration wa s measured before, during and after ischaemia. Neurological deficit wa s evaluated for 3 days after ischaemia. Neurological outcome was bette r in sevoflurane anaesthetized animals, regardless of the plasma gluco se concentration, compared with nitrous oxide-fentanyl controls. This indicates that differences in plasma glucose concentrations do not acc ount for the cerebral protection seen with sevoflurane.