Cerebral Oximetry Not a Lifesaver for Extremely Preterm Infants

Treatment guided by cerebral oximetry monitoring for the first 72 hours after birth failed to improve survival for extremely preterm infants, the SafeBoosC-III trial found.

At 36 weeks postmenstrual age, 35.2% of the oximetry group had either died or experienced a severe brain injury compared with 34% of the usual-care group (RR 1.03, 95% CI 0.90-1.18, P=0.64), reported Mathias Lühr Hansen, MD, PhD, of Rigshospitalet in Copenhagen, Denmark, and co-authors of the phase III randomized trial published in the New England Journal of Medicine.

Cerebral oximetry had been proposed as a way to alert neonatal ICU clinicians to low cerebral blood flow so any respiratory therapy could be adjusted to minimize the risk of brain damage. The potential downside, however, is that such additional equipment -- consisting of near-infrared light sensors strapped onto the baby's head -- may disturb and actually harm preterm infants.

Despite the negative results of their trial, Hansen and colleagues suggested several reasons not to give up on cerebral oximetry for babies born extremely preterm. Participating ICU clinical staff did not have to establish basic competence in this technology, so the involvement of people with little or no experience may have affected the trial's results. Moreover, monitoring only covered a small period of time, they said.

Notably, according to the SafeBoosC-III group, causes of death among infants in both groups included central nervous system injury, necrotizing enterocolitis, immaturity, and respiratory distress syndrome, among others.

"Assessment of the causes of death revealed fewer deaths from necrotizing enterocolitis in the oximetry group than in the usual-care group and more deaths attributed to severe brain injury in the oximetry group than in the usual-care group," the authors wrote. "These differences are probably chance findings; notably, the overall frequency of necrotizing enterocolitis was not lower in the oximetry group than in the usual-care group."

In the earlier SafeBoosC-II trial, cerebral oximetry conferred a reduction in cerebral hypoxia and hyperoxia. However, that study was not powered to detect clinical harms or benefits.

A total of 1,601 infants underwent randomization as part of the present study, with 785 patients placed in the oximetry treatment group and 816 in the usual treatment group. Researchers alone were blinded regarding each participant's treatment assignment.

Patients were from 70 different sites from throughout Asia, North America, and Europe.

Infants who were in the oximetry groups were given an oximetry monitoring probe that had near-infrared light sources and sensors which was attached to the patient's head for 72 hours. Sensor readings were then used to monitor the infant and to provide treatment options based on results.

Infants in the usual-care group did not undergo monitoring with cerebral oximetry but received treatment and monitoring as usual.

Severe brain injury parameters were described in the study as intraventricular hemorrhage of grade 3 or 4, cystic periventricular leukomalacia, post-hemorrhagic ventricular dilatation, cerebellar hemorrhage, and cerebral atrophy.

The overall incidence of serious adverse events did not differ between the two groups (85.1% vs 86.5%). Only four serious adverse reactions were observed -- all skin injuries from managing the oximetry equipment in the oximetry group.

Limitations to the study include a lack of blinded assessment regarding exploratory outcomes, a small number of infants undergoing scans both early and late in their treatment, and a lack of data on cerebral oxygenation results, all of which could have influenced results.

Follow-up at age 2 years is ongoing to assess neurodevelopmental and other outcomes, according to Hansen and colleagues.

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