[The effect of lidocaine on brain edema and neural function].

Recently lidocaine (Ld) has been reported to have beneficial effects on neural suppression caused by experimental cerebral ischemia or spinal cord injury. In this paper, the effects of Ld on brain edema, local cerebral blood flow (lCBF), and neural function in the thalamocortical and cortical structures were experimentally studied. Vasogenic brain edema was induced by exposure of the cat's cerebral surface to the air in the manner of Prados et al. The dura mater over the left cerebral hemisphere was resected, and the brain was exposed to room air for 12 hours. The animals were divided into two groups. In the control group of 31 cats, Ld was not administered. In the treated group of 8 cats, Ld (4.5 mg/kg) was given intravenously immediately after the beginning of the air-exposure and thereafter administered as a drip infusion at the rate of 2 mg/kg/hour. In the untreated group, 12 hours after exposure, the cerebral water content measured by gravimetry in the cortex, white matter and thalamus increased by approximately 1.9, 4.1, 0.7%, respectively, compared to the control values. Local CBF measured by the hydrogen clearance method decreased to about 71, 57 and 56% of the control value, respectively. The latency of the N1 component of the somatosensory evoked response (SER) was prolonged significantly 6 hours after air-exposure. The amplitude of the direct cortical response (DCR) decreased significantly 6 hours after air-exposure, and became approximately 50% of the control 12 hours after exposure.(ABSTRACT TRUNCATED AT 250 WORDS)