The Problem of the Preterm Lung: Definitions, History, and Epidemiology

Abstract

Survival of the preterm infant has improved dramatically over the past several decades. Access to neonatal intensive care units (NICU), improved nutrition, exogenous surfactant, advances in respiratory support, and minimally invasive surgical techniques have all contributed to an improvement in survival (Stoll et al. JAMA 314(10):1039–1051, 2015 [1]). Nevertheless, morbidity and mortality remains high, particularly in the extremely low birth weight infant. Worldwide, preterm birth was the leading cause of childhood mortality in 2013, accounting for 965,000 deaths out of the 6.3million deaths among children who died prior to 5 years of age (Liu et al. Lancet 385(9966):430–440, 2015) [2]. In 2014, 9.6 % of live births in the United States were considered preterm (i.e., born at <37 weeks gestation) (Martin et al. NCHS Data Brief 216:1–8, 2015; Hamilton et al. Natl Vital Stat Syst 64(12):1–64, 2015) [3, 4]. Many of these preterm infants developed pulmonary sequelae, ranging from mild respiratory symptoms that resolve over time to chronic respiratory failure requiring tracheostomy placement and mechanical ventilation. Although the lung parenchymal and small airways disease of bronchopulmonary dysplasia is one of the more common complications of prematurity, pulmonary sequelae in preterm infants can encompass virtually every part of the respiratory system. Since all aspects of the respiratory system can be affected, preterm infants may present with a variety of respiratory phenotypes, which in turn can lead to significant variation in care and outcomes (Guaman et al. Am J Perinatol32(10):960–967, 2015; Lapcharoensap et al. JAMA Pediatr 169(2):e143676, 2015) [5, 6]. In this chapter, we describe common pulmonary complications of prematurity and their epidemiology, including prevalence and risk factors, where known.