A 1-day-old boy is brought to the emergency department due to worsening cyanosis. He was delivered at home via spontaneous vaginal delivery. The mother received no prenatal care and is unsure of the gestational age at delivery. The neonate did well after delivery and has breastfed several times. Two hours ago, he developed rapid breathing and cyanosis. On examination, the patient is hypotensive. Pulse oximetry from the right hand is 80% on room air and does not improve with 100% inspired oxygen. Physical examination shows a diffusely cyanotic infant. Cardiac examination reveals tachycardia, a regular rhythm, and no murmur. The patient is tachypneic but has normal breath sounds bilaterally. Chest x-ray is normal. Echocardiography is pending. Laboratory results are as follows: Which of the following is the best next step in the management of this patient?

Question

A 1-day-old boy is brought to the emergency department due to worsening cyanosis.  He was delivered at home via spontaneous vaginal delivery.  The mother received no prenatal care and is unsure of the gestational age at delivery.  The neonate did well after delivery and has breastfed several times.  Two hours ago, he developed rapid breathing and cyanosis.  On examination, the patient is hypotensive.  Pulse oximetry from the right hand is 80% on room air and does not improve with 100% inspired oxygen.  Physical examination shows a diffusely cyanotic infant.  Cardiac examination reveals tachycardia, a regular rhythm, and no murmur.  The patient is tachypneic but has normal breath sounds bilaterally.  Chest x-ray is normal.  Echocardiography is pending.  Laboratory results are as follows:  Which of the following is the best next step in the management of this patient?

Quizplus · Accepted Answer

11ec25c8_d62f_b41c_bc81_69ba9201b10b_MD0003_00 This 1-day-old neonate has rapid onset of hypotension, cyanosis, and hypoxia that fails to improve with 100% inspired oxygen (hyperoxia challenge). This presentation most likely reflects a ductal-dependent congenital heart defect, with sudden clinical deterioration after an initial normal period suggesting that closure of the patent ductus arteriosus (PDA) has affected blood flow. In ductal-dependent cyanotic heart disease, blood flow from the right ventricle to the lungs is interrupted; instead, a right-to-left shunt of deoxygenated blood occurs (eg, across a septal or atrial defect). At birth, the PDA (which connects the aorta to the main pulmonary artery) is open, allowing the deoxygenated blood to flow from the aorta through the PDA to the lungs. As the PDA begins to close in the first 24 hours of life, pulmonary blood flow decreases, more deoxygenated blood is delivered systemically, and the cyanosis worsens. With some ductal-dependent defects (eg, hypoplastic left heart syndrome, coarctation of the aorta), a PDA is required to provide adequate systemic (rather than pulmonary) blood flow; as the PDA closes, poor perfusion and hypotension develop. hypoplastic left heart syndrome A ductal-dependent heart defect requires that the PDA be maintained. Prostaglandin E1 is a vasodilator that prevents PDA closure, thereby maintaining pulmonary or systemic blood flow, depending on the cardiac lesion. It can be administered even after the PDA has closed because it may help reestablish duct patency (as in this patient who no longer has the classic machine-like murmur associated with PDA). Infusion can begin before a definitive diagnosis is made. (Choice A) Indomethacin is a nonsteroidal anti-inflammatory drug that inhibits prostaglandin formation and facilitates closure of the PDA. It can be administered in neonates with a large, isolated PDA (eg, continuous, machine-like murmur) that fails to close, because these patients are at increased risk of heart failure and pulmonary hypertension from left-to-right shunting. In this infant, closure of the PDA would worsen his condition. (Choice B) Partial exchange transfusion is used to lower the hematocrit in infants with polycythemia. Polycythemia can cause hypoxia and cyanosis, but this infant's hematocrit is within normal limits. (Choice D) Sildenafil is a pulmonary vasodilator used in the treatment of persistent pulmonary hypertension of the newborn. This infant's sudden deterioration, hypotension, and low pulse oximetry measured in a preductal extremity (ie, right hand) suggest congenital heart disease rather than pulmonary hypertension. (Choice E) Surfactant can be administered for severe respiratory distress syndrome (RDS). RDS is more common in preterm infants, presents immediately after birth, and has ground-glass opacities on x-ray. Educational objective: As the patent ductus arteriosus closes, ductal-dependent congenital heart disease presents with cyanosis if pulmonary blood flow is obstructed or hypotension if systemic blood flow is obstructed. Prostaglandin E1 maintains the patency of the ductus arteriosus and is life-saving in infants with ductal-dependent congenital heart disease. References: Reappraisal of the prostaglandin E1 dose for early newborns with patent ductus arteriosus-dependent pulmonary circulation. (http://www.ncbi.nlm.nih.gov/pubmed/23590954) The critically ill infant with congenital heart disease. (http://www.ncbi.nlm.nih.gov/pubmed/26226862)

A 1-Day-Old Boy Is Brought to the Emergency Department Due