Case 2: Feeding Intolerance Following Topical Atropine Instillation in a Premature Infant

An extremely low-birthweight female newborn, weighing 545 g, is born at 23 weeks of gestation via cesarean section. Following a pregnancy complicated by preterm labor with prolonged rupture of membranes and positive maternal group B Streptococcus status, the newborn requires positive pressure ventilation, chest compressions, intubation, and surfactant administration in the delivery room. After initial stabilization, she is admitted to the NICU. She receives continuous positive pressure ventilation on day 37 after birth and is ultimately weaned to room air. She initially receives enteral feeds with breast milk and gradually advances to full enteral feeds by day 40 after birth. Within a week of tolerating full enteral feeds, she makes a transition to 24 kcal/oz of formula because of insufficient maternal breast milk supply. Her eyes are regularly screened for retinopathy of prematurity (ROP) from 31 weeks’ postmenstrual age (PMA). Before each ROP screening, she receives cyclopentolate/phenylephrine and proparacaine ophthalmic eye drops. Her initial eye examination reveals bilateral zone 1 stage 1 ROP. After the diagnosis of bilateral zone 2 stage 3 ROP with plus disease is made at PMA of 36 weeks, she is successfully treated with laser ablation therapy to the peripheral avascular retina of both eyes after a brief period of having nothing orally for 4 hours. Her enteral feeds are resumed later on the same day after laser surgery. She is subsequently started on daily ophthalmic 0.5% atropine drops and tobramycin/dexamethasone ophthalmic drops 4 times a day. On postoperative day 1, she is noted to have tachycardia with pulses ranging from 190 to 200 beats/min 1 hour after ophthalmic atropine is applied. She continues to have intermittent tachycardia, but enteral feeds are continued as she continues to have normal physical examination …