Influence of midazolam premedication on intraoperative EEG signatures in elderly patients

• Main Authors: Windmann, Victoria (Author), Spies, Claudia (Author), Brown, Emery Neal (Author), Kishnan, Devika (Author), Lichtner, Gregor (Author), Koch, Susanne (Author)
• Other Authors: Massachusetts Institute of Technology. Institute for Medical Engineering & Science (Contributor), Massachusetts Institute of Technology. Institute for Data, Systems, and Society (Contributor), Picower Institute for Learning and Memory (Contributor), Massachusetts Institute of Technology. Department of Brain and Cognitive Sciences (Contributor), Harvard University- (Contributor)
• Format: Article
• Language: English
• Published: Elsevier BV, 2020-06-23T18:04:40Z.
• Subjects: Article
• Online Access: Get fulltext

 Objective: To investigate the influence of midazolam premedication on the EEG-spectrum before and during general anesthesia in elderly patients. Methods: Patients aged ≥65 years, undergoing elective surgery were included in this prospective observational study. A continuous pre- and intraoperative frontal EEG was recorded in patients who received premedication with midazolam (Mid, n = 15) and patients who did not (noMid, n = 30). Absolute power within the delta (0.5-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), and beta (12-25 Hz) frequency-bands was analyzed in EEG-sections before (pre-induction), and after induction of anesthesia with propofol (post-induction), as well as during general anesthesia with either propofol or volatile-anesthetics (intra-operative). Results: Pre-induction, α-power of Mid patients was lower compared with noMid-patients (α-power: Mid: −10.75 dB vs. noMid: −9.20 dB; p = 0.036). After induction of anesthesia Mid-patients displayed a stronger increase of frontal α-power resulting in higher absolute α-power at post-induction state, (α-power: Mid −3.56 dB vs. noMid: −6.69 dB; p = 0.004), which remained higher intraoperatively (α-power: Mid: −2.12 dB vs. noMid: −6.10 dB; p = 0.024). Conclusion: Midazolam premedication alters the intraoperative EEG-spectrum in elderly patients. Significance: This finding provides further evidence for the role of GABAergic activation in the induction of elevated, frontal α-power during general anesthesia.