フレイル患者のリスク評価と術前管理

Preoperative Risk Assessment and Management of Frail Patients

はじめに

　高齢化の進行により，手術を受ける患者の高齢化と併存疾患の増加が進み，周術期管理におけるリスク評価の重要性はいっそう高まっている。フレイル（frailty）は，多臓器の生理的予備能が低下し，ストレスに対する脆弱性が亢進した状態を指す概念であり，術後合併症や死亡，在院日数延長と独立して関連することが報告されている。従来のリスクスコアのみではこの脆弱性を十分に反映できないことから，国際的には術前段階でのフレイル評価の導入が強く推奨されている。また，フレイルは不可逆的な虚弱状態ではなく，栄養，運動，心理社会的支援など多職種による適切な介入により改善しうる可逆的状態であり，術前最適化の重要なターゲットと位置づけられている。本論文では，フレイルの概念と代表的評価法を概説し，周術期における意義，管理の現状，そして今後の課題について整理する。

　The aging population of Japan and other countries has led to a steady increase in older surgery candidates with multiple comorbidities, making the accuracy of the assessment of patients’ perioperative risk increasingly important. Frailty, defined as a state of decreased physiological reserve and heightened vulnerability to stressors, is independently associated with postoperative complications, mortality, and prolonged hospital stay. Because traditional risk scores do not fully capture this vulnerability, international guidelines now strongly recommend incorporating a frailty assessment into each preoperative evaluation. Among the available tools, the Cardiovascular Health Study（CHS）criteria and the Clinical Frailty Scale（CFS）are most widely used, with a CFS score of 4 indicating pre-frailty and a score ≥5 indicating frailty. Importantly, frailty is not an irreversible condition；rather, it is a potentially modifiable state that can be improved through multidisciplinary interventions including nutritional optimization, exercise-based rehabilitation, and psychosocial support. Recent meta-analyses have demonstrated that multimodal preoperative ‘prehabilitation’ reduces major postoperative complications and shortens the hospital stay. Anesthesiologists play a pivotal role in this process by identifying patient frailty at preoperative clinics, tailoring the anesthetic management accordingly, and coordinating early multidisciplinary interventions. This review summarizes the concept and assessment of frailty, its perioperative implications, and the current challenges in establishing structured evaluation and intervention pathways for frail surgical patients.