British researchers have found that more than half of children who were born at 25 weeks or less have abnormal lung function and are twice as likely as their full-term peers to have a diagnosis of asthma. The study published in the American Journal of Respiratory and Critical Care Medicine followed a national cohort of extremely preterm infants to age 11.
Of 307 children who survived to age 11, 182 completed satisfactory baseline spirometry, 129 (71%) of who had had bronchopulmonary dysplasia. In addition to the finding that 56% of extremely preterm (EP) children had abnormal baseline spirometry, indicating impaired lung function and that one in four had diagnosis of asthma, 27% had a positive bronchodilator response, indicating that their airway obstruction was at least partially reversible. Furthermore, while nearly two-thirds (65%) had not had any respiratory symptoms for the past 12 months, nearly one-half (48%) of non-symptomatic EP children had abnormal spirometry results.
Even though the EP children were asymptomatic despite lung function impairment, researchers worry such symptoms may reappear in later life in the form of early onset chronic obstructive lung disease. Therefore, there is a continuing need to monitor these children beyond childhood.
Lead study investigator Janet Stocks, PhD, professor of respiratory physiology at the University College London, Institute of Child Health, suggests that adult chest physicians need to become more aware of the potential long-term respiratory impact of preterm birth and include neonatal details when taking medical histories.
“In theory, preterm survivors of modern neonatal care, who have been treated with ante-natal steroids and postnatal surfactant and subjected to far gentler ventilatory regimes than in the past, should have far less evidence of airway injury than their predecessors,” said Stocks. “The persistence of airway obstruction in these children is likely multi-factorial in nature, potentially reflecting the impact of extreme preterm birth per se and the vulnerability of such immature lungs even to low ventilatory pressures or oxygen concentrations.”