A 10-minute-old neonate is evaluated in the delivery room for low oxygen saturation and difficulty breathing. The patient was born at 36 weeks gestation to a 37-year-old mother whose pregnancy was complicated by poorly controlled type 2 diabetes mellitus. Membranes were ruptured 3 hours prior to delivery, and the fluid was clear. Apgar scores were 5 and 7 at 1 and 5 minutes, respectively. Temperature is 36.9 C (98.4 F), pulse is 166/min, and respirations are 70/min. Examination shows cyanosis of the lips and mucous membranes. The patient is grunting and has intercostal and subcostal retractions. Cardiac examination shows a 1/6 systolic ejection murmur at the left upper sternal border. Breath sounds are decreased bilaterally. The abdomen is soft with no organomegaly. Pulses are 2+ in all extremities. Pulse oximetry on room air is 64% in the right hand and foot. An orogastric tube is placed, and the patient is started on continuous positive airway pressure with supplemental oxygen. Pulse oximetry improves to 82%. Chest radiograph is shown in the image below:
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Blood cultures are obtained, and intravenous antibiotics are started. Which of the following is the most appropriate pharmacotherapy for this patient?
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This neonate with central cyanosis (ie, involving lips, mucous membranes) has significant improvement of hypoxia with administration of oxygen, making a primary pulmonary pathology most likely. In this case, increased work of breathing (eg, retractions), decreased breath sounds, and bilateral ground-glass opacities on chest x-ray are consistent with neonatal respiratory distress syndrome (RDS). RDS is a condition in which immature and/or inadequate surfactant production results in alveolar collapse and diffuse atelectasis.
The greatest risk factor for RDS is prematurity; however, poorly controlled gestational diabetes also increases the risk by delaying the normal maturation of surfactant. Maternal hyperglycemia causes fetal hyperglycemia and, in turn, fetal hyperinsulinism. High levels of insulin antagonize cortisol, which results in delayed maturation of phosphatidylcholine and phosphatidylglycerol, vital phospholipid components of surfactant.
RDS management includes respiratory support (eg, continuous positive airway pressure) to provide positive end-expiratory pressure and exogenous surfactant. Surfactant decreases alveolar surface tension, which increases compliance, prevents collapse, and improves lung expansion. Endogenous surfactant production after birth typically results in symptom improvement within a week.
(Choice A) Corticosteroids are given to women in preterm labor to stimulate fetal surfactant production prior to delivery, decreasing the risk of RDS. Corticosteroids play no role in neonatal RDS management.
(Choice B) Indomethacin, which closes a patent ductus arteriosus, is not indicated in the immediate newborn period when the ductus is physiologically open. Indications include hemodynamically significant left-to-right shunting causing heart failure symptoms (eg, failure to thrive, fatigue), not cyanosis.
(Choice C) Nitric oxide, a pulmonary vasodilator, treats persistent pulmonary hypertension of the newborn, which can complicate RDS but typically causes differential cyanosis (oxygen saturation of right hand > foot), not seen in this patient. The ventilation/perfusion mismatch seen in RDS is due to areas of the lung that are perfused but not ventilated and would therefore not improve with increased pulmonary perfusion.
(Choice D) Prostaglandin maintains ductus arteriosus patency for suspected cyanotic congenital heart disease. Unlike this patient, hypoxia due to right-to-left shunting through the ductus would not improve with oxygen administration. Moreover, this patient's chest x-ray findings suggest pulmonary disease, and cardiac examination is most consistent with an innocent murmur.
Educational objective:
Neonatal respiratory distress syndrome presents with increased work of breathing, hypoxia responsive to oxygen, and ground-glass opacities on x-ray; management includes exogenous surfactant administration. Neonates of mothers with diabetes and poor glycemic control are at increased risk due to delayed fetal lung maturation.