Respiratory mechanics during and after anaesthesia for major vascular surgery

To evaluate the effects of major vascular surgery on respiratory mechanics, 11 patients undergoing general anaesthesia for abdominal aortic surgery we re studied. Before aortic cross-clamping, chest wall elastance and resistan ce both increased (by 126% and 58%, respectively) when surgical retractors were placed. After aortic cross-clamping, lung elastance increased by 29%, accompanied by a decrease in cardiac index (22%) and an increase in pulmona ry (17%) and systemic (15%) vascular resistance. After aortic unclamping, l ung elastance decreased, although it remained higher than baseline values ( by 12%). All cardiovascular variables returned to the values obtained befor e aortic cross-clamping.