Spinal cord blood flow following subarachnoid tetracaine

Spinal cord and spinal dural blood flow in the cervical, thoracic and lumbosacral regions were measured in dogs using the radioactive microsphere technique. Measurements were taken before and 20 and 40 minutes after lumbar subarachnoid injection of one of the following: physiologic saline; tetracaine 20 mg or tetracaine 20 mg with epinephrine 200 micrograms. No significant change in spinal cord or spinal dural blood flow occurred following subarachnoid physiologic saline or tetracaine with epinephrine. Dogs receiving subarachnoid tetracaine demonstrated a significant increase in lumbosacral spinal cord, and thoracic and lumbosacral dural blood flow at 20 and 40 minutes following injection. Cervical dural blood flow was significantly increased at 40 minutes after subarachnoid tetracaine. Lumbar subarachnoid tetracaine (20 mg) produces a regional spinal cord and generalized dural hyperemia which is prevented by the addition of epinephrine (200 micrograms).