Establishment of an algorithm for predicting postoperative delirium using EEG analysis

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K16556
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 55050:Anesthesiology-related
• Research Institution: Hirosaki University
• Principal Investigator: Kinoshita Hirotaka 弘前大学, 医学部附属病院, 助教 (70897660)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 術後譫妄 / α波 / 脳波 / 好中球リンパ球比 / 脳内炎症 / 脆弱な脳 / 尿酸 / 高齢者

Outline of Final Research Achievements

We have investigated whether EEG during general anesthesia is useful as a means of early prediction for "neuroinflammation", which is considered to be a pathological mechanism of postoperative delirium. We reported the relative ratio of the alpha power is significantly lower in patients with postoperative delirium underwent highly invasive surgeries such as head and neck reconstruction and esophageal cancer surgery. Rather than age and neutrophil-lymphocyte ratios, which have been thought to be associated with postoperative delirium, the relative ratio of the alpha power reflected "vulnerable brain" and is the most useful marker for predicting postoperative delirium. In addition, we reported that the usefulness of preoperative neutrophil-lymphocyte ratios as a predictive marker for preoperative delirium in highly invasive malignant surgery.

Free Research Field

麻酔科学

Academic Significance and Societal Importance of the Research Achievements

全身麻酔中の脳波から術後譫妄を予測できるようになったことで、麻酔科医が術後譫妄に対し介入できる可能性を拓げた。また、麻酔導入時点で術後譫妄の発症がある程度規定されていることを脳波解析により客観的に証明したことで、術前の予防介入の重要性を示すことができた。全身麻酔中の脳波、特にα波は「脳の脆弱性」を示唆しており、α波の出現は術後譫妄予防に向けた術前介入の指標となりうる。また、加齢や術前の全身炎症を示唆する好中球リンパ球比との関連を探ることによって、術後譫妄の病態機序解明に向け一助となったと考えている。