Effects of deep barbiturate coma on acute spinal cord injury in the cat

The effects of barbiturate administration on experimental balloon-induced spinal cord injury were tested in cats. Somatosensory evoked potentials from sciatic nerve stimulation were obtained before trauma and every 60 minutes after it up to the sixth hour, when the animals were killed. Eight cats received no barbiturate treatment. On histologic examination the traumatic lesion was found to be extensive (mean, 72.8% of total cross section of the cord area), sparing dorsal columns only in six cats. Somatosensory evoked potentials were absent in two cats and profoundly modified (that is, the late waves were absent) in six cats at the sixth hour. Eight cats were given a continuous infusion for 1 hour of intravenous thiopental sodium (total dose, 65-90 mg/kg) starting 30 minutes after trauma. In these eight cats, the extent of the traumatic lesion was significantly reduced (8.8% of the cord area). Among them, three animals presented with unaltered somatosensory evoked potentials (that is, with the presence of both primary components and late waves) at the sixth hour. It was concluded that thiopental sodium improves the response of the spinal cord to trauma, both at an anatomic and at a functional level.