Measurement of spinal cord blood flow by an inhalation method and intraarterial injection of hydrogen gas

Purpose: This study was performed to determine spinal cord blood flow using the H-2 clearance method. Methods: In 12 dogs we measured blood flow determined by hydrogen clearance techniques (BF) in both gray and white matter by spinal cord puncture, and compared the results with BF measured by a catheter inserted intrathecally to avoid spinal cord injury. We studied direct intraarterial and intravenous injection of hydrogen in addition to the inhalation method because hydrogen is an explosive gas. Results: BF measured intrathecally with catheters adherent to either the ventral or the dorsal funiculus did not differ significantly from that of the gray matter. BF measured with a catheter inserted into the epidural space was about one fourth of the BF measured intrathecally. Values measured by the intraarterial injection method did not differ significantly from those obtained by the inhalation method. Conclusions: BF measured with a catheter inserted intrathecally reflects blood flow in the gray matter of the spinal cord. Using intraarterial injection of H-2, BF was safely and accurately measured while avoiding the risk of explosion.