Microdialysis to optimize cord perfusion and drug delivery in spinal cord injury.
- Publisher: John Wiley & Sons
OBJECTIVE: There is lack of monitoring from the injury site to guide management of patients with acute traumatic spinal cord injury. Here we describe a bedside microdialysis monitoring technique for optimizing spinal cord perfusion and drug delivery at the injury site. METHODS: 14 patients were recruited within 72 hours of severe spinal cord injury. We inserted intradurally at the injury site a pressure probe, to monitor continuously spinal cord perfusion pressure, and a microdialysis catheter, to monitor hourly glycerol, glutamate, glucose, lactate and pyruvate. The pressure probe and microdialysis catheter were placed on the surface of the injured cord. RESULTS: Microdialysis monitoring did not cause serious complications. Spinal cord perfusion pressure 90 - 100 mmHg and tissue glucose >4.5 mM minimized metabolic derangement at the injury site. Increasing spinal cord perfusion pressure by ∼10 mmHg, increased the entry of intravenously administered dexamethasone at the injury site three-fold. INTERPRETATION: This study determined the optimum spinal cord perfusion pressure and optimum tissue glucose concentration at the injury site. We also identified spinal cord perfusion pressure as a key determinant of drug entry into the injured spinal cord. Our findings challenge current guidelines, which recommend maintaining mean arterial pressure at 85 - 90 mmHg for a week after spinal cord injury. We propose that future drug trials for spinal cord injury include pressure and microdialysis monitoring to optimize spinal cord perfusion and maximize drug delivery at the injury site. This article is protected by copyright. All rights reserved.