Effects of Continuous Infusion of Low-dose Human Atrial Natriuretic Peptide (hANP) on the Lungs during Cardiac Surgery

Objective: The objective of this study was to determine the effects of a continuous infusion of low-dose hANP on the lungs during cardiac surgery in patients under cardiopulmonary bypass (CPB).Methods: We analyzed 30 consecutive cases of cardiac surgery performed at our hospital from 2007–2008. The patients were divided into a group that received hANP (hANP group) or a group that received saline and no hANP (N-hANP group). We measured various parameters before and after surgery using a PiCCO monitor.Result: There were no differences in the preoperative characteristics between the groups, although urine volume during the operation was significantly greater in the hANP group. After surgery, there were no significant differences between the groups in cardiac output index (CI), global enddiastolic volume index (GEDVI), intrathoracic blood volume index (ITBI), pulmonary blood volume index (PBI), extravascular lung water index (ELWI) and pulmonary vascular permeability index (PVPI), total protein, and creatine. In contrast, interleukin-6 (IL-6) and renin were significantly lower, and albumin was significantly higher in the hANP group.Conclusion: We found that low-dose hANP during open cardiac surgery inhibited the secretion and plasma activity of IL-6 and renin. Although there were no differences in lung circulatory parameters such as the amount of fluid in the pulmonary blood vessels between the two groups, we believe that the strong diuretic effect of hANP reduced third-space fluid retention caused by CPB.