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The aim of this study is to evaluate the effect of fetal cardiac bypass on the production and secretion of fetal atrial natriuretic peptide (ANP) in the goat. Eighteen pregnant goats, at days 120 to 140 of gestation, were randomly divided into control (n = 8) and bypass (n = 10) groups. The control group underwent a sham procedure involving fetal sternotomy and cannulation. The bypass group underwent fetal cardiac bypass using a centrifugal pump for 30 min. Fetuses in the bypass group exhibited hypoxia, hypercapnia, and acidosis during and after cardiac bypass. The pulse index (PI) of the umbilical artery in the bypass group increased significantly after cardiac bypass compared with the control group. Tei indices of the left and right ventricles in the bypass group increased remarkably after cardiac bypass. Plasma troponin I levels in the bypass group increased significantly compared with that of the control group. Plasma ANP levels increased markedly in the bypass group after cardiac bypass, and the difference between two groups was significant. Transcriptional levels of ANP mRNA in the fetal heart elevated remarkably in the bypass group compared with the control group at 2 h after the bypass. A significant positive correlation between plasma ANP levels and Tei indices of the ventricles, plasma troponin I was observed (left ventricular Tei index, r = 0.606, P < 0.01; right ventricular Tei index, r = 0.581, P < 0.01; plasma troponin I, r = 0.275, P < 0.05). In conclusion, fetal cardiac bypass promoted the production and secretion of ANP and was associated with fetal cardiac dysfunction.

Objective: To study the hormonal and metabolic responses of fetal lamb during cardiopulmonary bypass., Methods: Six pregnant ewes underwent fetal cardiopulmonary bypasses with artificial oxygenators and roller pumps for 30 minutes, which maintained the blood gas value at the fetal physiological level. The fetal blood pressure, heart rate, pH value and blood lactate levels were monitored. The levels of catecholamine, cortisol and insulin were measured pre-bypass and then again 30 minutes later. The blood glucose and free fatty acid levels were monitored continuously during the bypass. Fetal hepatic PAS staining was also carried out., Results: There were no changes before and during the bypass in fetal blood pressure, heart rate and blood gas. However, pH values decreased and blood lactate levels increased (P < 0.05). The fetal catecholamine and cortisol levels increased significantly (P < 0.01), while the levels of insulin did not change. The blood glucose and free fatty acid levels increased at the beginning of the bypass (P < 0.01), and then gradually slowed down during the bypass. The fetal hepatic PAS staining showed that hepatic glycogen was consumed in large amounts. After 30 minutes of bypass, the fetal lamb would not survive more than 1 hour., Conclusion: The fetal lamb has a strong negative reaction to cardiopulmonary bypass.