Intraoperative Frontal EEG Alpha Power is Associated with Post-Operative Mortality and Other Adverse Outcomes

Rory V Mather; Ryan D Nipp; Gustavo Balanza; Tom A D Stone; Rodrigo Gutierrez; Praachi Raje; Masaya Higuchi; Ran Liu; Laura A Santa Cruz Mercado; Edward A Bittner; Hiroko Kunitake; Patrick L Purdon

doi:10.1097/ALN.0000000000005315

Intraoperative Frontal EEG Alpha Power is Associated with Post-Operative Mortality and Other Adverse Outcomes

Anesthesiology. 2024 Nov 27. doi: 10.1097/ALN.0000000000005315. Online ahead of print.

Authors

Rory V Mather^{1

2

3

4}, Ryan D Nipp⁵, Gustavo Balanza⁴, Tom A D Stone^{4

6}, Rodrigo Gutierrez^{4

7}, Praachi Raje⁶, Masaya Higuchi^{8

9}, Ran Liu⁴, Laura A Santa Cruz Mercado¹⁰, Edward A Bittner³, Hiroko Kunitake⁶, Patrick L Purdon⁴

Affiliations

¹ Harvard/MIT MD-PhD Program, Boston, MA, USA.
² Harvard-MIT Program in Health Sciences and Technology, Cambridge, MA, USA.
³ Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA.
⁴ Department of Anesthesia, Perioperative and Pain Medicine, Stanford University School of Medicine, Palo Alto, CA, USA.
⁵ Section of Hematology/Oncology, Department of Internal Medicine, University of Oklahoma Health Sciences Center, Stephenson Cancer Center, Oklahoma City, OK, USA.
⁶ Department of Surgery, Massachusetts General Hospital, Boston, MA, USA.
⁷ Department of Anesthesia and Perioperative Medicine, University of Chile, Santiago, Chile.
⁸ Department of Medicine, Division of Palliative Care and Geriatric Medicine, Massachusetts General Hospital, Boston, MA, USA.
⁹ Department of Neurosurgery, Graduate School of Medicine, Tohoku University, Sendai, Miyagi, Japan.
¹⁰ Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Hospital, Boston, MA, USA.

PMID: 39601585
DOI: 10.1097/ALN.0000000000005315

Abstract

Background: With estimated global post-operative mortality rates at 1-4% leading to approximately 3-12 million deaths per year, an urgent need exists for reliable measures of perioperative risk. Existing approaches suffer from poor performance, place a high burden on clinicians to gather data, or do not incorporate intraoperative data. Prior work demonstrated that intraoperative anesthetics induce prefrontal EEG oscillations in the alpha band (8-12Hz) that correlate with post-operative cognitive outcomes.

Methods: We analyzed a retrospective cohort of 1,081 patients undergoing surgery with general anesthesia at Massachusetts General Hospital with intraoperative EEG recordings. The association between EEG alpha power and adverse outcomes were characterized using statistical models that were fitted on propensity weighted data. Our primary outcome was post-operative mortality, measured from date of surgery to date of death or last follow-up. Secondary outcomes included mortality within pre-specified time windows (30-days, 90-days, 180-days, and 1-year), hospital and PACU lengths of stay, discharge to long-term care, and 30-day hospital readmission.

Results: Alpha power was associated with mortality risk (HR = 0.92, 95% CI:[ 0.85, 0.99], p=0.039). Within specified time windows, alpha power was associated with 30-day mortality (OR = 0.81, 95% CI: [0.66, 0.95], p=0.010), 90-day mortality (OR = 0.68, 95% CI: [0.55, 0.79], p<0.001), 180-day mortality (OR = 0.75, 95% CI: [0.66, 0.83], p<0.001), and 1-year mortality (OR = 0.85, 95% CI: [0.79, 0.91], p<0.001). Additionally, alpha power was associated with discharge to long-term care (OR = 0.91, 95% CI: [0.86, 0.96], p<0.001). We did not find significant associations among alpha power and 30-day readmission and hospital or PACU lengths of stay.

Conclusions: Intraoperative EEG alpha power is independently associated with post-operative mortality and adverse outcomes, suggesting it could represent a broad measure of post-operative physical resilience and provide clinicians with a low-burden, personalized measure of post-operative risk.