Cardiopulmonary bypass

Women with structural cardiac or coronary artery disease may have an attenuated ability to adapt to the cardiovascular changes associated with pregnancy. The use of cardiopulmonary bypass (CPB) may be necessary and unavoidable for many urgent or emergent cardiac surgical repairs. Accurate maternal and fetal risk assessment prior to surgery is fundamental for preoperative care. CPB may cause significant alterations in patient physiology, with virtually every organ system affected. The main pathophysiological changes that can affect the fetus under CPB are uterine contraction, placental hypoperfusion, and fetal hypoxia. There are three primary aims in the anesthetic management of patients undergoing CPB: providing safe maternal hemodynamic management, avoiding teratogenic agents, and minimizing effects of CPB that may induce premature labor. The application of cardioplegia may need to be more frequent with the maintenance of high flows during CPB, especially if normothermia or only mild hypothermia is employed.