高齢消化器外科手術例における退院時認知機能について—術後せん妄との関連性

Cognitive function at discharge in elderly gastrointestinal surgery cases: Association with postoperative delirium

　目的：外科手術例においては術後にせん妄をきたすことがある．せん妄は一過性の急性脳機能障害であるが，高齢者において術後せん妄(POD)から回復した後の認知機能について検討した報告はない．本研究では，消化器外科手術後にPODを呈した高齢者に対して，手術前後における認知機能の変化について後方視的に検討した．方法：対象は2019年8月から2020年8月の間に松阪市民病院消化器外科に外科的切除目的で入院した13名(年齢：81.5±5.2　男・女：10・3)である．13例をPODの有無で2群に分類し，両群において，Geriatric Nutritional Risk Index(GNRI)で評価した栄養状態と，術前と退院時の神経心理学的検査を比較検討した．結果：GNRIはPOD群が非POD群に比し低値であった．また神経心理学的検査結果は，POD群において退院時のTrail Making Test-Bで有意な反応時間の延長を認めた．結語：栄養状態が比較的悪い高齢消化器外科術後症例はPODを示しやすく，PODは退院時の認知機能に影響を及ぼす可能性が示唆された．

　Surgery can cause postoperative delirium (POD), a transient acute brain dysfunction. To date, there are no reports examining cognitive function after recovery from POD in the elderly. In this study, we retrospectively examined changes in cognitive function before and after surgery in elderly patients who presented with POD after gastrointestinal surgery. The subjects were 13 patients (age:81.5±5.2 male/female:10/3) admitted to the Department of Gastroenterology, Matsusaka Municipal Hospital for surgical resection between August 2019 and August 2020. The patients were classified into two groups according to the presence or absence of POD. Nutritional status as assessed by the Geriatric Nutritional Risk Index (GNRI) between the two groups and neuropsychological examination before surgery and at discharge were compared. GNRI was lower in the POD group than in the non-POD group. Neuropsychological test results also showed a significant increase in reaction time on the Trail Making Test-B at discharge in the POD group. Thus, elderly gastrointestinal postoperative patients with relatively poor nutritional status were more likely to show POD. It was also suggested that POD may affect cognitive function at the time of hospital discharge.