Authors: Asif H et al.
Anesthesiology 144(4):1012–1015, April 2026
Summary:
This exploratory study examines how intraoperative variables affect spinal cord blood flow (SCBF) in humans using laser speckle contrast imaging, a technique that provides real-time, high-resolution perfusion mapping during spinal surgery.
The key finding is that spinal cord blood flow behaves differently from cerebral blood flow in several important ways. Increasing sevoflurane concentration did not significantly change SCBF, in contrast to the brain where volatile anesthetics typically increase blood flow. This suggests that spinal cord vasculature is less sensitive to anesthetic-driven vasodilation.
In contrast, arterial carbon dioxide tension (PaCO₂) had a strong and consistent effect. Increasing PaCO₂ significantly increased SCBF, confirming that carbon dioxide is a potent vasodilator in the spinal cord—similar to its well-known effects in the brain. Interestingly, higher sevoflurane concentrations appeared to amplify the responsiveness of SCBF to CO₂.
Temperature of irrigation fluid had little impact on SCBF, indicating that spinal cord perfusion is more influenced by core physiology than local temperature changes during surgery.
The study also provides evidence that spinal cord autoregulation exists in humans. In patients without spinal cord injury, SCBF returned to baseline after changes in mean arterial pressure (MAP), demonstrating intact autoregulation. However, this mechanism was impaired in patients with traumatic spinal cord injury, leading to persistent changes in blood flow with MAP fluctuations.
Finally, the study demonstrated neurovascular coupling in the spinal cord—electrical stimulation increased SCBF rapidly, reflecting coupling between neuronal activity and blood flow.
Overall, the findings suggest that spinal cord perfusion is tightly regulated, influenced strongly by CO₂, and capable of autoregulation and neurovascular coupling—but differs from cerebral physiology in its response to anesthetics.
Key Points:
- Sevoflurane concentration does not significantly affect spinal cord blood flow
- PaCO₂ is a major determinant of spinal cord perfusion
- Spinal cord autoregulation is present but impaired after injury
- Neurovascular coupling exists in the spinal cord
- Irrigation fluid temperature has minimal impact on perfusion
What You Should Know:
CO₂ matters more than anesthetic concentration for spinal cord perfusion. That’s the practical takeaway. If you’re worried about cord perfusion, focus on ventilation—not volatile dose. And in injured cords, autoregulation may be gone, so MAP changes matter even more.
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