加齢による腹部大動脈瘤手術時の血行動態の差異について

Senile alteration of hemodynamics in surgery of abdominal aneurysm

　加齢により腹部大動脈瘤手術時の血行動態に差異があるか否かを待機的手術例50例で検討し，高齢者の手術成績の向上に役立てようとした。70歳以上22例（75歳未満13例，75歳以上9例）と70歳未満28例（65歳未満17例，65歳以上11例）と分けて検討した。術前の容量負荷試験では70歳未満群は平均3.66から4.07，4.42l／min／m²と心係数が増加するのに比し，70歳以上群は平均3l／min／m²台の推移であった。心係数は大動脈血流遮断にて減少し，その減少は70歳以上群で大で，2.46±0.72から2.04±0.56l／min／m²と減少した。遮断解除では心係数は増加した。平均肺動脈楔入圧は両群とも術中，徐々に増加傾向を示した。さらに，70歳前後を5歳間隔で分けて詳細にみると，術前の容量負荷試験では70歳以上群で低心機能を示したのは70歳以上75歳未満の症例であり，75歳以上では70歳未満と同等の心機能を示した。しかし術中および術後は75歳以上症例では低心機能を示す傾向にあった。

Hemodynamic measurements were performed before, during and after surgery of aneurysmal patients. Fifty non-ruptured infrarenal aneurysmal patients undergoing elective aortic reconstructions were studied. Patients who had no evidence of heart disease were divided into two groups by age. The older group consisted of 22 patients older than 70 years of age, and the younger group consisted of 28 patients younger than 70 years. The results may be summarized as follows; ① Hemodynamics before surgery (volume loaded test): For 500 ml albumine infusion within 30 minutes, cardiac indices of the older group kept below 4.0l/min/m², whereas in the younger group there was an increase from 3.66 to 4.42l/min/m². ② Hemodynamics during surgery: Peripheral resistance increased by cross-clamping of the aorta, and decreased after removal of the aorta, and decreased after removal of the cross clamp in both groups. Cardiac indices dropped dur-ing cross-clamping of the aorta. The older group dropped more noticeably compared with the younger group, for instance, at one minute after cross-clamp-ing, the older group was 2.04±0.56, and the younger group was 2.44±0.0.56l/min/m². Mean pulmonarywedge pressure increased gradually during surgery in both groups.③ Hemodynamics after surgery: The older group kept lower cardiac indices compared with the younger group, but not so noticeably. These results indicated that older patients have low cardiac function for preload and afterload change. We will be confronted by an increasing number of older patients in the near future. Hemodynamic managements of aortic reconstructions in the elderly might become important.