CEREBROSPINAL-FLUID LACTATE AND ELECTROLYTE LEVELS FOLLOWING EXPERIMENTAL SPINAL-CORD INJURY

CSF lactate, Na+, K+, Ca2+, Mg2+ and Cl- levels were determined for 17-21 days following experimental spinal cord compression in cats. Laminectomies were performed at L-2 under general anesthesia with aseptic techniques. Paraplegia was produced by applying a 170-gm weight transdurally for 5 min. Significant increases in CSF lactate levels were observed on the 1st-9th days post injury with peak levels (50% above normal) occurring at day 5. The only significant postinjury CSF electrolyte changes were elevation in Ca2+ concentration on days 3, 9, 11, 13 and 15; elevation in K+ concentration on days 9 and 11; and decline in Cl- levels on the 1st day. The CSF K+ increase probably reflected cellular loss of K+ from damaged tissue, whereas the Ca2+ rise may have resulted from increased CSF protein levels. The prolonged elevation of CSF lactate indicates that tissue hypoxia plays a role in spinal cord compression paralysis and that there is a continuing hypoxia of metabolically active spinal cord tissue for several days post injury.