The relationship between plasma concentration of mature adrenomedullin and jugular venous oxygen saturation during and after cardiopulmonary bypass.

Abstract

Adrenomedullin (AM), a vasodilatory peptide, increases during cardiac surgery. However, the physiological role of AM during cardiac surgery remains unclear. AM dilates cerebral arterioles and increases cerebral blood flow in rats. Therefore, we investigated whether AM is related to cerebral oxygen balance during cardiac surgery. In nine patients undergoing coronary artery bypass grafts, plasma concentrations of mature AM from the radial artery (mAMa) and jugular bulb (mAMj) were measured, and jugular venous oxygen saturation was obtained before surgery (baseline), before aortic cross-clamp (preclamp), after aortic declamp (postclamp), and 20 min after weaning from the cardiopulmonary bypass (post-CPB). Plasma concentrations of mAMa and mAMj were significantly increased at postclamp (P < 0.01 for both) and post-CPB (P < 0.01 for both) compared with baseline values. SjO(2) correlated with plasma mAMj concentrations at preclamp (r = 0.79, P < 0.01), postclamp (r = 0.71, P < 0.05), and post-CPB (r = 0.72, P < 0.05), as well as with mAMa concentrations at preclamp (r = 0.79, P < 0.01) and postclamp (r = 0.72, P < 0.05). This suggests a relationship between AM and cerebral oxygen balance during cardiac surgery. Plasma concentrations of mature-form adrenomedullin, a vasodilatory peptide, was correlated with jugular venous oxygen saturation during cardiac surgery. This suggests a relationship between adrenomedullin and cerebral oxygen balance during cardiac surgery.