Mechanical Ventilation-Associated Changes in Hippocampal Electroencephalogram: A Cross-Species Study in Humans and Rats.

AIMS: To identify hippocampal intracranial electroencephalography (iEEG) signatures associated with mechanical ventilation (MV) in humans and rats and assess their translational relevance.

METHODS

Hippocampal iEEG was recorded in humans (n = 9) and rats (n = 12; MV + propofol vs. propofol-only, n = 6 per group). Power spectral density (PSD), spectral exponent (SE), and trajectory entropy (TE) were quantified to characterize MV-related neural changes.

RESULTS

MV was associated with consistent directional hippocampal iEEG changes across species, with increased PSD, SE, and reduced TE. In humans, PSD increases were mainly posterior (delta-alpha; p < 0.05), while in rats they spanned dorsal theta-gamma (p < 0.05). SE increased in humans (38.5%, p < 0.001) and rats (26.6%, p < 0.01), while TE decreased in humans (11.2%, p < 0.001) and rats (6.9%, p = 0.001). Cross-species differences were greater in the posterior/dorsal hippocampus (PSD: d = -0.924 [-1.521 to -0.328]; SE: d = 0.944 [0.346 to 1.542]) than in anterior/ventral regions. In rats, MV increased low-frequency power and SE and reduced dorsal TE under propofol.

CONCLUSIONS

MV is associated with comparable hippocampal iEEG changes across species, supporting the rat model for MV-related neural dynamics. Nevertheless, the findings are EEG-restricted and lack general translational validity for brain injury.

CLINICAL TRAIL REGISTRATION: ClinicalTrails.gov (NCT06480162; Zhonghua Shi; May 8, 2024).