Index of Suspicion in the Nursery: Persistent Tachypnea

Presentation

At 2 days of age, a term female newborn infant is evaluated for tachypnea. She was born at 40 weeks’ gestation, with birthweight 4.6 kg, to a 34-year-old G2P2 woman via normal spontaneous vaginal delivery. Maternal history is pertinent for well-controlled gestational diabetes mellitus and hypothyroidism treated with levothyroxine. Prenatal laboratories are significant for group B Streptococcus positivity for which the mother was adequately treated. All other prenatal laboratories are unremarkable. The delivery was complicated by a nuchal cord and apnea requiring positive pressure ventilation for 10 seconds. Apgar scores were 6 at 1 minute and 9 at 5 minutes. A review of her vital signs from the newborn nursery reveal the following: heart rate, 128 beats per minute; respiratory rate, 52 breaths per minute; and oxygen saturation, 89% in room air that had improved without supplemental oxygen.

Her respiratory rate is 82 breaths per minute, and pre- and postductal oxygen saturations are 97% in room air. On physical examination, she is consistently tachypneic, as noted by multiple caregivers, with minimal subcostal retractions but without grunting or flaring. The remainder of her examination is within normal limits. Basic metabolic panel, capillary blood gas, and complete blood count are all normal. A chest radiograph is read as unremarkable (Fig 1A). Blood cultures are drawn, but given a low risk for sepsis, antibiotics are not started. A cardiologist is consulted for sustained tachypnea and a new grade I/VI systolic murmur in the left lower sternal border. An echocardiogram …