Monitoring Spinal Cord Tissue Oxygen in Patients With Acute, Severe Traumatic Spinal Cord Injuries

OBJECTIVES: To determine the feasibility of monitoring tissue oxygen tension from the injury site (p(sct)o(2)) in patients with acute, severe traumatic spinal cord injuries. DESIGN: We inserted at the injury site a pressure probe, a microdialysis catheter, and an oxygen electrode to monitor for up to a week intraspinal pressure (ISP), spinal cord perfusion pressure (SCPP), tissue glucose, lactate/pyruvate ratio (LPR), and p(sct)o(2). We analyzed 2,213 hours of such data. Follow-up was 6-28 months postinjury. SETTING: Single-center neurosurgical and neurocritical care units. SUBJECTS: Twenty-six patients with traumatic spinal cord injuries, American spinal injury association Impairment Scale A-C. Probes were inserted within 72 hours of injury. INTERVENTIONS: Insertion of subarachnoid oxygen electrode (Licox; Integra LifeSciences, Sophia-Antipolis, France), pressure probe, and microdialysis catheter. MEASUREMENTS AND MAIN RESULTS: p(sct)o(2) was significantly influenced by ISP (p(sct)o(2) 26.7 +/- 0.3 mm Hg at ISP > 10 mmHg vs p(sct)o(2) 22.7 +/- 0.8 mm Hg at ISP <= 10 mm Hg), SCPP (p(sct)o(2) 26.8 +/- 0.3 mm Hg at SCPP < 90 mm Hg vs p(sct)o(2) 32.1 +/- 0.7 mm Hg at SCPP >= 90 mm Hg), tissue glucose (p(sct)o(2) 26.8 +/- 0.4 mm Hg at glucose < 6 mM vs 32.9 +/- 0.5 mm Hg at glucose >= 6 mM), tissue LPR (p(sct)o(2) 25.3 +/- 0.4 mm Hg at LPR > 30 vs p(sct)o(2) 31.3 +/- 0.3 mm Hg at LPR <= 30), and fever (p(sct)o(2) 28.8 +/- 0.5 mm Hg at cord temperature 37-38 degrees C vs p(sct)o(2) 28.7 +/- 0.8 mm Hg at cord temperature >= 39 degrees C). Tissue hypoxia also occurred independent of these factors. Increasing the Fio(2) by 0.48 increases p(sct)o(2) by 71.8% above baseline within 8.4 minutes. In patients with motor-incomplete injuries, fluctuations in p(sct)o(2) correlated with fluctuations in limb motor score. The injured cord spent 11% (39%) hours at p(sct)o(2) less than 5 mm Hg (< 20 mm Hg) in patients with motor-complete outcomes, compared with 1% (30%) hours at p(sct)o(2) less than 5 mm Hg (< 20 mm Hg) in patients with motor-incomplete outcomes. Complications were cerebrospinal fluid leak (5/26) and wound infection (1/26). CONCLUSIONS: This study lays the foundation for measuring and altering spinal cord oxygen at the injury site. Future studies are required to investigate whether this is an effective new therapy.

Automated summary

This study examines the feasibility of monitoring tissue oxygen tension in patients with acute, severe traumatic spinal cord injuries. The results show that tissue oxygen tension is influenced by various factors, including intraspinal pressure, spinal cord perfusion pressure, tissue glucose levels, lactate/pyruvate ratio, and fever. In patients with motor-incomplete injuries, fluctuations in tissue oxygen tension correlate with fluctuations in limb motor score.