Haemodynamic and metabolic consequences of aortic occlusion during abdominal aortic surgery.

We have studied the haemodynamic and metabolic effects of application and removal of the infrarenal aortic crossclamp in 20 patients during aortic reconstructive surgery for repair of aneurysmal or occlusive disease. A highly significant positive correlation was detected between the change in systemic vascular resistance (SVR) associated with application of the aortic crossclamp and the change in base deficit (BD) associated with its removal (r = 0.851; P = 0.001). There was no difference in regression analysis (P = 0.21) or mean change of SVR and BD (P = 0.73) in patients with either aneurysmal or occlusive disease. In addition, the maximum increase in mixed venous serum lactate concentration correlated positively with the duration that the aortic crossclamp was applied (r = 0.717, P = 0.0297). These observations suggest the importance of the collateral circulation in the development of metabolic acidosis during aortic surgery.