General Anesthesia Elevates High-Frequency Oscillation Rates in Nonepileptic Brain Regions
Abstract number :
2.325
Submission category :
9. Surgery / 9B. Pediatrics
Year :
2023
Submission ID :
567
Source :
www.aesnet.org
Presentation date :
12/3/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Hiroshi Uda, MD, PhD – Wayne State University
Ethan Firestone, MD-PhD candidate – Pediatrics – Wayne State University; Naoto Kuroda, MD – Pediatrics – Wayne State University; Kazuki Sakakura, MD, PhD – Pediatrics – Wayne State University; Masaki Sonoda, MD, PhD – Neurosurgery – Yokohama City University; Yu Kitazawa, MD, PhD – Pediatrics – Wayne State University; Ros Whelan, MD – Neurosurgery – Wayne State University; Michael Cools, MD – Neurosurgery – Wayne State University; Sandeep Sood, MD – Neurosurgery – Wayne State University; Aimee Luat, MD – Pediatrics – Wayne State University; Eishi Asano, MD, PhD – Pediatrics – Wayne State University
Rationale: Although the rate of high-frequency oscillations (HFOs) typically increases in the seizure onset zone, the effect of anesthetic conditions on HFO rates in nonepileptic brain regions remains to be determined across four brain lobes. By comparing the HFO rate in nonepileptic electrode sites between extraoperative and intraoperative intracranial EEG (iEEG) recordings, we aim to enhance our understanding of the relationship between anesthetic agents and HFO rates.
Methods: The inclusion criteria for this observational study were as follows: drug-resistant focal epilepsy, intraoperative iEEG recording immediately after intracranial electrode placement, extraoperative iEEG recording, International League Against Epilepsy class 1 outcome after focal resection, and iEEG sampling from all four lobes. The sole exclusion criterion was a history of previous resective epilepsy surgery. During intraoperative iEEG recording, we initially kept isoflurane levels below 1%, then switched to sevoflurane to enhance the rate of interictal epileptiform discharges in the epileptogenic zone. Sevoflurane levels were then progressively increased from 2% to 3%, and finally to 4%. We detected HFO events at 80-300 Hz using the Hilbert algorithm implemented in RIPPLELAB. A linear mixed-model analysis compared HFO rates at nonepileptic electrode sites under five conditions, including extraoperative slow-wave sleep (control condition), isoflurane below 1%, sevoflurane at 2%, 3%, and 4%. The model incorporated age, sex, number of oral anti-seizure drugs, sampled lobe, and anesthetic condition as fixed-effect variables, with patient intercepts treated as random-effect variables.
Results: Five children (aged 8-13 years; three males) met the eligibility criteria. We analyzed 336 nonepileptic electrode sites, including 89 from the frontal lobe, 125 from the temporal lobe, 79 from the parietal lobe, and 43 from the occipital lobe. The mean HFO rate (±standard deviation) was 1.95±2.85/min during slow-wave sleep, 2.62±3.63/min during isoflurane, 2.99±3.77/min during 2% sevoflurane, 4.57±4.30/min during 3% sevoflurane, and 4.83±4.80/min during 4% sevoflurane. Compared to slow-wave sleep, the HFOs rate was increased by isoflurane by 0.71/min (p=0.007), 2% sevoflurane by 1.09/min (p< 0.001), 3% sevoflurane by 2.61/min (p=0.000), and 4% sevoflurane by 3.22/min (p=0.000). Neither age, sex, number of anti-seizure drugs, nor sampled lobes showed significant effects on HFO rates.
Surgery