Depending on gestational age, preterm infants may have structurally immature lungs which lack the surfactant necessary to prevent collapse of their air sacs during exhalation.([FOOTNOTE=Schmölzer G, Kumar M, Pichler G, et al. Non-invasive versus invasive respiratory support in preterm infants at birth: systematic review and meta-analysis. BMJ. 2013;347:f5980.],[ANCHOR=],[LINK=]),([FOOTNOTE=Purandare CN. Fetal lung maturity. J Obstet Gynecol India. 2005;55(3):215-217.],[ANCHOR=],[LINK=]) These characteristics may put ventilated preterm neonates at risk for lung injury such as bronchopulmonary dysplasia, which may put them at risk for ongoing respiratory symptoms and long-term functional abnormalities.1
Premature babies have extreme central nervous system vulnerability and may be susceptible to the long-lasting changes in physical structure and operation of the brain associated with premature birth.([FOOTNOTE=Salmaso N, Jablonska B, Scafidi J, Vaccarino FM, Gallo V. Neurobiology of premature brain injury. Nat Neurosci. 2014;17(3):341-346.],[ANCHOR=],[LINK=]),([FOOTNOTE=Newnham CA, Inder TE, Milgrom J. Measuring preterm cumulative stressors within the NICU: the Neonatal Infant Stressor Scale. Early Hum Dev. 2009;85(9):549-555.],[ANCHOR=],[LINK=]) The most common types of brain injury seen in premature infants are diffuse injury to the white matter as well as gray matter and hippocampal abnormalities.3
Beyond prematurity itself, low blood oxygen levels resulting from immature lung development,3 nutritional stress,([FOOTNOTE=Kuenen K, van Elburg RM, van Bel F, Benders MJNL. Impact of nutrition on brain development and its neuroprotective implications following preterm birth. Pediatr Res. 2015;77(1):148-155.],[ANCHOR=],[LINK=]) and environmental stresses([FOOTNOTE=Smith GC, Gutovich J, Smyser C, et al. Neonatal intensive care unit stress is associated with brain development in preterm infants. Ann Neurol. 2011;70(4):541-549.],[ANCHOR=],[LINK=]) have been linked to brain injury.
Alterations in brain structure due to prematurity may persist into adolescence and are associated with long-term cognitive difficulties, "particularly those involved with language and executive functions, and psychiatric illnesses including autistic spectrum and anxiety disorders."3
Retinopathy of prematurity (ROP) is an eye disease that primarily affects premature infants who weigh 1500 grams or less at birth.([FOOTNOTE=Jordan CO. Retinopathy of prematurity. Pediatr Clin N Am. 2014;61:567-577.],[ANCHOR=],[LINK=]) Approximately 14% of childhood blindness in the United States is associated with ROP, making it the third leading cause of blindness in American children.8
ROP is thought to be caused by growth of abnormal blood vessels in the retina which may bleed, which can cause retinal scarring and may eventually lead to retinal detachment.([FOOTNOTE=Facts About Retinopathy of Prematurity (ROP). National Eye Institute Web site. https://www.nei.nih.gov/health/rop/rop. Accessed December 3, 2014.],[ANCHOR=],[LINK=])
Major risk factors for ROP include high blood levels of oxygen (due to treatment with excessive supplemental oxygen) and low birth weight.8 Oxygen saturation between 90% and 95% appears to be the safest target to reduce the risk of ROP in premature infants.8