Impaired Macroscopic Cerebrospinal Fluid Flow by Sevoflurane in Humans during and after Anesthesia.

Summary

In 16 healthy adults, 2% sevoflurane decreased cisternal CSF signal amplitude and disrupted global cortical connectivity and gray matter-CSF coupling on fMRI, with persistent deficits 45 minutes after emergence. Findings suggest sevoflurane impairs macroscopic CSF flow by disrupting coherent global gray matter activity.

Key Findings

• Sevoflurane decreased cisternal CSF peak-to-trough amplitude (median difference 1.00; P=0.013).
• Global cortical connectivity and gray matter–CSF coupling were disrupted during anesthesia (P<0.001 and P=0.002).
• Impairments in global connectivity and gray matter–CSF coupling persisted 45 minutes after emergence (P=0.022 and P=0.008).

Clinical Implications

While not practice-changing yet, the data support investigating anesthetic choice, depth, and timing in patients at risk for neurocognitive disorders, and motivate perioperative strategies that protect glymphatic function.

Limitations

• Small sample size (n=16) of healthy volunteers; indirect fMRI-based CSF flow indices.
• Single anesthetic (sevoflurane) and short post-anesthesia observation window (45 minutes).

Future Directions

Extend to surgical cohorts (older adults, cognitive impairment), compare anesthetics (volatile vs. intravenous), and evaluate links to postoperative delirium/cognitive decline and long-term CSF dynamics.