No decrease observed in oxygen therapy use for preterm infants
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Although the use of less invasive ventilation strategies after birth have increased substantially, oxygen dependence at 36 weeks has not significantly declined, with no improvement in lung function in later childhood, according to a recent study in The New England Journal of Medicine.
“Assisted ventilation has changed substantially since the 1970s, when ventilation delivered through an endotracheal tube predominated,” Lex W. Doyle, MD, from the department of neonatal services at the Royal Women’s Hospital, and colleagues wrote. “Although assisted ventilation has become less invasive during the past 25 years, it is unclear whether assisted ventilation has been associated with improvements in short-term or long-term respiratory function.”
To assess whether the use of assisted ventilation and oxygen therapy in neonates, as well as lung function at 8 years for extremely premature infants, had changed over time, the researchers conducted a longitudinal follow-up study of those born at gestational age of 36 weeks or less in Victoria, Australia. All extremely premature infants were born in 1991 and 1992 (n = 225), 1997 (n = 151) or 2005 (n = 170).
Data on duration of assisted ventilation, as well as type of ventilation, duration of oxygen therapy, and oxygen requirements at 36 weeks’ gestational age, were collected prospectively. At 8 years, the children’s expiratory airflow was measured, and age, height, ethnic group and sex were examined for z scores.
Over time, the length of time in which assisted ventilation was used rose, with a substantial increase observed in the use of less invasive measures, including nasal continuous positive airway pressure. Despite this increase, oxygen therapy and oxygen dependence rates at 36 weeks’ gestational age rose.
Additionally, in 2005, airflows measured at 8 years were significantly worse than those previously observed. The researchers note that the mean difference in z scores for the ration of forced expiratory volume in 1 second to forced vital capacity was –0.75 (95% CI, –1.07 to –0.44; P < .001) between scores in 1991-1992 and 2005. When comparing 2005 and 1997, the average difference was –0.53 (95% CI, –0.86 to –0.19; P =.002).
“We speculate that prolonged periods of oximetry may be partly responsible for the increasing rate of oxygen dependence observed in 2005 and that this trend may translate into worse lung function when children reach the age at which they will attend school,” Doyle and colleagues wrote. – by Katherine Bortz
Disclosure: The researchers provide no relevant financial disclosures.