The birth of a child before the completion of a full-term pregnancy, before the 37th week of gestation, leads to a great deal of concern for the mother and newborn when it comes to their health, respectively. Typically, premature babies are placed on breathing support — 30 breaths per minute — because of their abnormal breathing patterns, which stem from the underdevelopment of their lungs. Now a study in the New England Journal of Medicine has found high-frequency oscillation (HFOV), equivalent to 600 breaths per minute, may improve lung function and cognitive skills in preemies during childhood, compared to conventional ventilation.
“Poorer lung function in adolescence could have further consequences later in life, such as making children more vulnerable to the damaging effects of smoking and infection,” said Anne Greenough, professor of clinical respiratory physiology at King's College London, in the press release. Currently, neonatal units provide preemies with conventional ventilation to assist their breathing, but this still leaves them susceptible to chronic respiratory problems during adolescence. However, through high-frequency breathing, there is a smaller volume of air being forced into the lungs which may cause less damage to the delicate organs than conventional therapy, and reduce the likelihood of future lung complications.
To investigate whether HFOV would be a better ventilation treatment than conventional ventilation for premature babies, a team of researchers at King's College London conducted a study on adolescents who were born before 29 weeks of gestation. The participants, 319 babies, who were randomly assigned to either HFOV or conventional ventilation, were followed from birth to adolescence. Follow-up data in respect to lung function and respiratory health, health-related quality of life, and functional status were compared in both groups. This was assessed with the use of questionnaires completed by the participants when they were 11 to 14 years of age.
The findings revealed children supported by HFOV had superior lung function across several measures between the ages of 11 and 14 than the children who had been supported by conventional ventilation at birth, according to Medical Xpress. Rapid breathing allowed preemies to breathe out more easily because a smaller volume of air is being forced into their lungs at birth. HFOV are gentler to preemies' tiny airways and can serve to prevent lung damage for those who will most likely need to be ventilated for long periods of time.
Furthermore, some cognitive skills were found to be enhanced in the HFOV group. The children’s teachers completed questionnaires in order to measure the academic achievement of preemies supported by HFOV after birth. This group was found to rate significantly higher in three of eight school subjects assessed: art and design, information technology and design, and technology, implying they had better visual design abilities than their counterparts.
"It is exciting that the differences are still there in adolescence,” Greenough said, the BBC reported. She believes preemies who have worse function, and are still having conventional therapy could be more vulnerable to the damaging effects of infection, or smoking later in life. The findings of this study could possibly change the use of ventilation in neonatal units, but several remain skeptical HFOV’s safety.
Although preemies are at high risk of developing breathing problems due to lung underdevelopment and damage from breathing support, there is concern over HFOV and its risk of neurodevelopmental problems. A 2001 study found there was an increased risk of bleeding into the brain in preemies who underwent HFOV. The researchers found early use of HFOV decreases exogenous surfactant requirements and could lead to severe brain bleeding. However, the authors of the recent study did not find evidence of adverse neurological effects in HFOV supported children.
According to March of Dimes, more than 450,000 babies are born prematurely in the U.S. each year. A baby who is born before 37 weeks of gestation is considered to be premature, while those born between 35 and 37 weeks are “late preterm” babies. Premature babies are at risk for more problems than full-term babies.
Alcazar-Paris M, Calvert S, Greenough A, et al. Late Outcomes of a Randomized Trial of High-Frequency Oscillation in Neonates. New England Journal of Medicine. 2014.
Andre C, Blanc T, Breart G, et al. Prospective Randomized Multicenter Comparison of High-Frequency Oscillatory Ventilation and Conventional Ventilation in Preterm Infants of Less Than 30 Weeks With Respiratory Distress Syndrome. Pediatrics. 2001.