Introduction: The current clinical practice guidelines for hemodynamic management of acute spinal cord injury (SCI) recommend that the mean arterial pressure be maintained between 85-90 mm Hg for the first seven days post-injury, with the use of vasopressors if necessary. A potentially important limitation with the present approach is the exclusive focus on mean arterial pressure, and not the spinal cord perfusion pressure. Our goal was to determine whether spinal cord perfusion pressure as measured with a lumbar intrathecal catheter is a more predictive measure of neurologic outcome than the conventionally measured mean arterial pressure.

Methods: Ninety-two acute individuals with acute SCI were enrolled in this multi-center prospective observational clinical trial. Mean arterial pressure and cerebrospinal fluid pressure were monitored during the first week post-injury. Neurologic impairment was assessed at baseline and at six-months post-injury. We used logistic regression, systematic iterations of relative risk, and Cox proportional hazard models to examine hemodynamic patterns commensurate with neurologic outcome.

Results: We found that spinal cord perfusion pressure (OR=1.039, p=0.002) is independently associated with positive neurological recovery. The relative risk for not recovering neurological function continually increased as individuals were exposed to spinal cord perfusion pressure below 50 mmHg. Individuals who improved in neurological grade dropped below spinal cord perfusion pressure of 50 mmHg less times than those who did not improve (p=0.012). This effect was not observed for mean arterial pressure or cerebrospinal fluid pressure. Those who were exposed to spinal cord perfusion pressure below 50 mmHg were less likely to improve from their baseline neurologic impairment grade (p=0.0056).

Conclusions: We demonstrate that maintaining spinal cord perfusion pressure above 50 mmHg is a strong predictor of improved neurological recovery following SCI. This suggests spinal cord perfusion pressure (as measured with a standard lumbar intrathecal catheter) can provide useful information to guide the hemodynamic management of acute SCI patients.

Patient Care: Our findings suggest that monitoring cerebrospinal fluid pressure with a simple lumbar intrathecal catheter can provide meaningful measures of spinal cord perfusion pressure. This will improve the hemodynamic monitoring of acute SCI patients and provides an opportunity to optimize neurologic recovery.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) discuss the difference between spinal cord perfusion pressure monitoring and mean arterial pressure monitoring, 2) describe the importance of monitoring cerebrospinal fluid pressure, and 3) discuss the potential benefits of optimizing spinal cord perfusion pressure in the acute phase after SCI.

References: Kwon BK, Curt A, Belanger LM, Bernardo A, Chan D, Markez JA, Gorelik S, Slobogean GP, Umedaly H, Giffin M, Nikolakis MA, Street J, Boyd MC, Paquette S, Fisher CG, Dvorak MF. Intrathecal pressure monitoring and cerebrospinal fluid drainage in acute spinal cord injury: a prospective randomized trial. J Neurosurg Spine. 2009 Mar;10(3):181-93. PubMed PMID: 19320576.