title: Continuous Monitoring and Visualization of Optimum Spinal Cord Perfusion Pressure in Patients with Acute Cord Injury.
abstract: The optimum spinal cord perfusion pressure (SCPP) after traumatic spinal cord injury (TSCI) is unknown. Here, we describe techniques to compute and display the optimum SCPP in real time. We recruited adults within 72 h of severe TSCI (American Spinal Injuries Association [ASIA] grades A-C). A pressure probe and a microdialysis catheter were placed on the injured cord. SCPP was computed as mean arterial pressure (MAP) minus intraspinal pressure (ISP), spinal pressure reactivity index (sPRx) as the running ISP/MAP correlation coefficient, and continuous optimum SCPP (cSCPPopt) as the SCPP that minimizes sPRx in a moving 4-h window. In 45 patients, we monitored ISP and blood pressure. In 14 patients, we also monitored injury site metabolism. cSCPPoptcould be computed 45% of the time. Mean cSCPPoptvaried by up to 60 mm Hg between patients. Each patient's cSCPPoptvaried with time (standard deviation 10-20 mm Hg). Color-coded maps showing the sPRx/SCPP curve evolution enhanced visualization of cSCPPopt. Periods when SCPP ≈ cSCPPoptwere associated with low injury site glucose, high pyruvate, and high lactate. Mean SCPP deviation from cSCPPoptcorrelated with worse neurological outcome at 9-12 months: ASIA grade improved in 30% of patients with <5 mm Hg deviation, 10% of patients with 5-15 mm Hg deviation, and no one with >15 mm Hg deviation. We conclude that real-time computation and visualization of cSCPPoptafter TSCI are feasible. cSCPPoptappears to enhance glucose utilization at the injury site and varies widely between and within patients. Our data suggest that targeting cSCPPoptafter TSCI might improve neurological outcome.
authors.affiliation: 1 Academic Neurosurgery Unit, St. George's, University of London , London, United Kingdom .
authors.forename: Suliang
authors.initials: S
authors.lastname: Chen
authors.affiliation: 2 Department of Clinical Neurosciences, Brain Physics Laboratory, Addenbrooke's Hospital, University of Cambridge , Cambridge, United Kingdom .
authors.forename: Peter
authors.initials: P
authors.lastname: Smielewski
authors.affiliation: 2 Department of Clinical Neurosciences, Brain Physics Laboratory, Addenbrooke's Hospital, University of Cambridge , Cambridge, United Kingdom .|3 Institute of Electronic Systems, Warsaw University of Technology , Warsaw, Poland .
authors.forename: Marek
authors.initials: M
authors.lastname: Czosnyka
authors.affiliation: 1 Academic Neurosurgery Unit, St. George's, University of London , London, United Kingdom .
authors.forename: Marios C
authors.initials: MC
authors.lastname: Papadopoulos
authors.affiliation: 1 Academic Neurosurgery Unit, St. George's, University of London , London, United Kingdom .
authors.forename: Samira
authors.initials: S
authors.lastname: Saadoun
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D064926:Neurophysiological Monitoring / Q000379:methods*; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D055815:Young Adult
keywords: autoregulation; blood pressure; critical care; spinal cord injuries; vasopressor agents