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5.09.2013

Eduardo Bancalari, M.D., Weighs in on Oxygen Therapy for Preemies in JAMA Editorial

Faced with conflicting studies about the optimal level of supplemental oxygen that extremely premature infants need to overcome respiratory failure but avoid other complications, Eduardo Bancalari, M.D., Director of the Division of Neonatology, suggests in an editorial published in The Journal of the American Medical Association (JAMA) that clinicians use higher, rather than lower, oxygenation targets within recommended ranges to assure the greatest chance of survival for the tiniest patients.

As Bancalari, professor of pediatrics and obstetrics and gynecology, and co-author Nelson Claure, M.Sc., Ph.D., research associate professor of pediatrics, note in their editorial, “Oxygenation Targets and Outcomes in Premature Infants,” neonatologists have opted in recent years to minimize the complications associated with oxygen therapy by reducing the oxygen saturation premature infants receive “despite little evidence for the efficacy and safety of this approach.” While that approach may limit retinopathy of prematurity (ROP), which can cause blindness, and bronchopulmonary dysplasia (BPD), which can scar the lungs, they said, it presents neonatal clinicians with “a difficult conundrum” because it also appears to increase mortality.

“If the long-term outcomes are not affected by the different saturation targets, should the shorter-term outcomes of (survival), severe ROP, and BPD be used to formulate a recommendation?” the authors asked. “After all, no other outcome is as important as survival.”

The conundrum they referred to was deepened by a new study on a Canadian Oxygen Trial that Bancalari’s editorial accompanied in the May 5 Online First edition of JAMA. Conducted in 25 hospitals with 1,201 extremely preterm infants, that study found no significant difference in the effect of reducing or increasing oxygen saturation rates on the disability or death of the babies within 18 months, the age at which neonatal study subjects are evaluated.

That finding conflicts in one important regard with two other clinical studies published in The New England Journal of Medicine that found that reducing oxygen saturation levels from a target of 91 to 95 percent to a target between 85 and 89 percent significantly decreased the incidence of retinopathy of prematurity, but increased mortality within the first 18 months of life. Conducted in the U.S. as part of the Neonatal Research Network of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, UM participated in the first study, which is known as SUPPORT, for Surfactant Positive Airway Pressure and Pulse Oximetry Trial.

An even higher increase in mortality with the lower oxygen target was observed in the second BOOST II (Benefits of Oxygen Saturation Targeting) trial, which was conducted in Australia, New Zealand and the United Kingdom.

In their editorial, Bancalari and Claure cited differences among the three studies as possible explanations for why the Canadian study, which used a similar at-risk population, similar oxygenation targets, and the same equipment, did not find the increased mortality with the lower saturation target described in SUPPORT and BOOST II. The differences included a revision in the software for pulse oximeters, which nurses use to measure and manage oxygen saturation in the blood, the varying ethnicities of the study subjects, who were born in different parts of the world, and tighter compliance by the Canadian researchers to the oxygen targets, which are difficult to constantly achieve in real-world clinical settings.

Given the mixed guidance from the three studies, Bancalari and Claure, who are the inventors of Clio, an automated system that controls inspired oxygen concentration now in clinical use in Canada, Europe and Latin America, concluded that targeting oxygen saturation between 90 and 95 percent appears to be “a reasonable approach” until the remaining questions raised by the three studies are answered or new evidence becomes available.

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