Journal of neurotrauma
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Journal of neurotrauma · Jan 1993
Surface and epidural lumbosacral spinal cord evoked potentials in chronic spinal cord injury.
Nine patients were examined in the chronic stage of spinal cord injury (12 to 56 months postinjury). Surface lumbosacral spinal cord evoked potentials (LSEPs) were obtained using electrodes placed over the S1, L2, L4, and T12 vertebral levels, referenced to a T6 surface electrode. Epidural LSEPs were obtained using a multielectrode lead placed percutaneously into the epidural space for evaluation of the efficacy of spinal cord stimulation for modification of pain and spasticity. ⋯ The LSEPs for the marginal group (n = 2, 1 incomplete and 1 complete) showed similar epidural/surface amplitude ratios. In the abnormal case (n = 1, complete) surface LSEPs were absent but epidural LSEPs were present but with stationary and propagating components of low amplitude. This study demonstrates the ability of the epidural LSEP to provide more information than the surface LSEP of the functional condition of the lumbosacral spinal cord, particularly regarding the character of the propagating action potentials and in cases when the surface LSEPs appear to be of very low amplitude or absent.
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Journal of neurotrauma · Jan 1993
Lactated Ringer's solution alleviates brain trauma-precipitated lactic acidosis in hemorrhagic shock.
To determine the influence of brain trauma on blood acid-base and lactate-pyruvate responses to hemorrhage, and the effect of lactated Ringer's solution on these responses, 30 anesthetized rats were assigned to four groups: hemorrhage (n = 7), hemorrhage following fluid percussion brain trauma (trauma-hemorrhage group) (n = 7), hemorrhage treated with lactated Ringer's solution (hemorrhage-resuscitation group) (n = 8), and hemorrhage following brain trauma treated with lactated Ringer's solution (trauma-hemorrhage-resuscitation group) (n = 8). The hemorrhage group showed no significant changes in pH, HCO3, and base excess after hemorrhage. Base excess and pH were significantly reduced after the hemorrhage in the trauma-hemorrhage group but were raised after resuscitation in the hemorrhage-resuscitation group. ⋯ Lactate rose significantly after hemorrhage in the hemorrhage group and was even higher in the trauma-hemorrhage group, but there were no differences between the hemorrhage versus hemorrhage-resuscitation or trauma-hemorrhage-resuscitation groups. Both brain trauma and lactated Ringer's solution increased pyruvate with marked reduction in the ratio of lactate to pyruvate. These data indicate that brain trauma precipitates blood lactate accumulation and metabolic acidosis after hemorrhage, and infusion of lactated Ringer's solution can relieve these disturbances.
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Early investigations involving central nervous system (CNS) temperature lowering to protect against the detrimental effects of hypoxia and ischemia were based on the observation that hypothermia reduces brain metabolism and energy consumption. The protective effects of hypothermia have been demonstrated in numerous experimental models of cerebral ischemia and recently in models of brain trauma. These observations also led to the application of hypothermia, in the form of local spinal cord cooling (LSCC), in animal models of experimental spinal cord injury (SCI). ⋯ The application of the technique itself is fraught with difficulties. It requires acute surgery in a traumatized patient, a wide multilevel laminectomy, and minimizing the time interval between injury and the application of spinal cord cooling. Recent studies in experimental brain ischemia strongly suggest that a drastic lowering of CNS temperature may be unnecessary to lessen the degree of tissue damage occurring following an ischemic brain injury.(ABSTRACT TRUNCATED AT 250 WORDS)