Preoperative management of hypoplastic left heart syndrome

Pediatricians are frequently involved in the care of cyanotic newborns in the labor and delivery room, as well as in the well baby nursery. Causes of hypoxia and cyanosis in the term newborn can be found within all physiological systems. Congenital heart structural diseases account for the largest diagnostic category. There have been significant advances during the past years in the diagnosis and treatment of neonates with critical congenital heart disease, especially in the field of pre- and post-operative intensive care. The term hypoplastic left heart syndrome (HLHS) describes a spectrum of cardiac structural abnormalities characterized by marked hypoplasia of the left ventricle and ascending aorta. Prenatal diagnosis, initial resuscitation and optimal preoperative management are key elements that allow the best opportunity for low mortality and normal neurodevelopment in affected newborns. Preoperatively, the goal is to achieve adequate systemic oxygen delivery. Patency of the ductus arteriosus (DA) is critical for survival until surgery. Blood flow to the pulmonary and systemic circulations should be nearly balanced (goal Qp/Qs ratio of 1). The immediate therapy for all infants with HLHS is an intravenous infusion of prostaglandin E1 (PGE1) in order to manipulate the DA and maintain ductal patency. Oxygen saturations of 75% to 85% by pulse oximetry suggest an adequate balance between systemic and pulmonary blood flow. Judicious use of inotropic support is initiated if evidence of low cardiac output is detected. Diuretics may be necessary to help alleviate the increased volume load on the right ventricle. The goal of respiratory management is to increase pulmonary vascular resistance and decrease systemic vascular resistance. Infants with HLHS who are born with a severely restricted or no inter-atrial communication, a rare occurrence, have profound hypoxemia. The severe restriction of blood flow across the atrial septum results in a life-threatening situation and these patients, which present with severe cyanosis and hemodynamic instability, require urgent postnatal cardiac catheterization to relieve the septal obstruction and improve oxygenation. Special attention should be paid to the prevention of brain injury and poor neurodevelopmental outcome. Care for infants with HLHS is complex, and often multiple specialists are involved. Despite an increase in the number of newborns with complex congenital heart disease and a growing percentage of patients with single-ventricle physiology, it is possible to care for this particular group of patients and achieve acceptable mortality risks, even in centres with no pediatric cardiac surgery facilities, if good preoperative management protocols are followed