Continuous lidocaine infusion and focal feline cerebral ischemia

We measured somatosensory evoked potentials, infarct size, and cerebral blood flow in 20 cats subjected to occlusion of the middle cerebral artery for 3 hours, followed by an equal period of reperfusion. The cats were randomized into a treatment group that received a continuous infusion of 2 mg/kg lidocaine hydrochloride or a control group that received an equivalent volume of normal saline. All 10 treated cats retained measurable evoked potentials throughout the experiment. In five control cats, evoked potentials disappeared completely at some point during the occlusion (difference between groups significant at p less than 0.001). Mean amplitude of the major cortical wave in the nine treated cats with cerebral infarcts was higher than that of the nine corresponding controls (p less than 0.05). Lidocaine reduced the mean +/- SEM size of the infarcts from 30.1 +/- 6.0% in the control group to 14.7 +/- 4.9% in the treated group (p less than 0.05). As blood flow was reduced in the infarct and peri-infarct zones in the control but not the treated cats, our results suggest that the beneficial effects of lidocaine may be due to preservation of blood flow in the ischemic zone.