Effect of intra-aortic magnesium on renal function during and after abdominal aortic surgery: A pilot study

Background: Infrarenal aortic cross-clamping causes renal vasoconstriction. Magnesium may protect against renal deterioration through its vasodilatory properties. Methods: Thirty patients with normal preoperative renal function undergoing infrarenal aortic cross-clamping for elective aortic surgery received magn esium (4 mmol) or saline into the aorta immediately after aortic cross-clam ping and again just before unclamping in a double-blind fashion. Pulmonary artery occlusion pressure was maintained greater than or equal to 15 mmHg. Five patients with magnesium were excluded due to need for intravenous nitr oglycerine because of myocardial ischaemia during the study. Results: Postoperative creatinine clearance remained unchanged in both grou ps. Urinary N-acetyl-beta-D-glucosaminidase excretion increased before and decreased after aortic crossclamping in both groups. The concentrations of glutathione peroxidase in serum were identical between the two groups. Conclusions:These data indicate that intra;aortic magnesium had no effect o n renal function during or after aortic crossclamping. (C) Acta Anaesthesio logica Scandinavica 44 (2000).