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Study Looks at Oxygen Saturation in Preemies


 

From the New England Journal of Medicine

Major Findings: Death before discharge occurred in 20% of the infants in the lower oxygen saturation, compared with 16% of those in the higher group. In contrast, severe retinopathy among the surviving infants occurred significantly less often in the lower group at 9%, compared with the higher group at 18%.

Data Source: The multicenter Surfactant, Positive Pressure, and Oxygenation Randomized Trial (SUPPORT) comprising 1,316 preterm infants from 24 weeks to 27 weeks and 6 days gestation.

Disclosures: SUPPORT was funded by the National Institutes of Health and by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Heart, Lung, and Blood Institute. One of the study co-authors, Dr. Krisa P. Van Meurs, disclosed receiving travel expenses from Ikaria Holdings. Dr. Colin Morley disclosed financial relationships with Dräger Medical and Fisher & Paykel.

Using lower target ranges of oxygen saturation in extremely preterm infants reduces the risk of severe retinopathy from oxygen toxicity, but increases the risk of death before discharge, according to one of two trials within the same neonatal study.

In the second trial, continuous positive airway pressure (CPAP) was determined to be an effective alternative to early surfactant administration followed by conventional intubation, with fewer complications.

Researchers in the multicenter Surfactant, Positive Pressure, and Oxygenation Randomized Trial (SUPPORT) used a 2×2 factorial design to compare two target ranges of oxygen saturation in 1,316 infants who were born between 24 weeks and 27 weeks 6 days of gestation. In addition, they compared intubation and surfactant treatment initiated within 1 hour after birth and CPAP treatment initiated in the delivery room with subsequent use of a limited ventilation strategy.

For the oxygen range arm of the study, the infants were randomly assigned to the lower oxygen saturation target range of 85%-89% or the higher target range of 91%-95%. At the same time, they were randomly assigned to receive the oxygen through a ventilator or through a CPAP machine.

The primary outcome of the oxygen saturation investigation was a composite of severe retinopathy of prematurity (defined as the presence of threshold retinopathy, the need for surgical ophthalmologic intervention, or the use of bevacizumab), death before hospital discharge, or both, wrote Dr. Waldemar A. Carlo of the University of Alabama at Birmingham, and colleagues.

Although there was no overall difference between the two oxygen saturation groups using the composite outcome measure, marked differences were observed when the two components of the measure were considered independently, the authors wrote. Specifically, death before discharge occurred in 20% of the infants in the lower target group compared with 16% of those in the higher group. In contrast, severe retinopathy among the surviving infants occurred significantly less often in the lower group, at 9%, compared with the higher group, at 18%. These findings, the authors note, “add to the concern that oxygen restriction may increase the rate of death among preterm infants.” As such, they advise exercising caution when considering a strategy that targets oxygen levels in the low range (N. Engl. J. Med. 2010;362:1959-69).

For the CPAP vs. early intubation/surfactant study arm, the primary outcome was death or bronchopulmonary dysplasia, defined by the need for supplemental oxygen at 36 weeks, wrote Dr. Neil N. Finer of the University of California at San Diego, and colleagues. After adjusting for gestational age, medical center, and family clustering, the need for supplemental oxygen was similar in both groups, although the CPAP infants less frequently required intubation or postnatal corticosteroids for bronchopulmonary dysplasia than the surfactant group, and they also required fewer days of mechanical ventilation and were more likely to be alive by day 7, the authors wrote.

Considering the lower complication rate, the findings “support consideration of CPAP as an alternative to routine intubation and surfactant administration in preterm infants,” the authors wrote (N. Engl. J. Med. 2010;362:1970-9).

In an accompanying editorial, Dr. Colin J. Morley of the University of Melbourne stressed that caution is warranted in interpreting the “most important outcome” linking the lower target oxygen saturation range and death before discharge. “Additional research is needed to clarify this finding,” he said. “There were no significant differences between the groups in short-term outcomes that have been associated with relative ischemia.”

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