SafeBoosC - a Phase II Trial

Background 25,000 infants are born extremely preterm every year in Europe. This group of infants carries a high risk of death and subsequent cerebral impairment for the infant, especially in the first 72 hours of life. Mortality is about 20%, and about 25% of survivors live with either cerebral palsy or low intelligence quotient. Preventative measures are keys to reducing mortality and morbidity in this population. There is evidence that the cerebral oxygenation time spent out of range (time with hypoxia or hyperoxia) is associated with poor outcome in infants. Near-infrared spectroscopy (NIRS) has been used to monitor tissue oxygenation since the mid-1980s, and quantification of oxygenation (rStO2) in a percentage from 0 to 100% has been possible for 10 years. From almost 400 preterm infants normal ranges of rStO2 has been determined to be from 55% to 85%. Still, there are no clinical trials and thus no solid evidence of the clinical utility of NIRS in preterm infants. Thus, research on the benefits and harms of cerebral monitoring using NIRS as a part of clinical management of premature infants is much needed.

Objectives The primary objective of the SafeBoosC trial is to examine if it is possible to stabilise the cerebral oxygenation of extremely preterm infants during the first 72 hours of life through the application of cerebral NIRS oximetry and implementation of an rStO2-specific clinical treatment guideline. We hypothesise that by using the specified treatment guideline to respond to cerebral monitoring readings outside the target range, we would reduce the burden of hypo- and hyperoxia and consequently reduce brain injury.

Trial design This is an investigator-initiated randomised, blinded, multinational, phase II feasibility clinical trial involving preterm infants from 12 European countries.

Inclusion criteria The inclusion criteria are: neonates born more than 12 weeks preterm (gestational age up to 27 weeks and 6 days); decision to conduct full life support; parental informed consent; and cerebral NIRS oximeter placed within 3 hours after birth.

Sample size With a 50% reduction of the area outside the normal range of oxygenation in %hours in the experimental group compared to the control group as the minimal clinically significant difference, a standard deviation of the area outside the normal range of 83.2 %hours, a type I error (alpha) of 5%, and a type II error of 0.05 (power of 95%) inclusion of 75 preterm infants in the experimental group and 75 preterm infants in the control group is required. The inclusion of twins are likely to decrease power, so it has been decided to increase sample size to 165 on a pragmatic basis of estimating intracluster correlation, control event rate, and incidence of twin births.

Intervention The premature infants will be randomised into one of two groups (experimental or control). Common is that both groups will have a cerebral oximeter monitoring device placed within three hours after birth. In the experimental group, the cerebral oxygenation reading is visible, and the infant will be treated accordingly using a defined treatment guideline. In the control group, the cerebral oxygenation reading is NOT visible, and the infant will be treated as usual.

Trial duration Monitoring by cerebral oximeter will be started as soon as possible and within 3 hours after birth and the intervention will last for 72 hours. Thereafter, each neonate will be followed up at term date (approximately three months after birth) and at 24 months after term date.

Outcome measures The primary outcome is the burden of hypo- and hyperoxia in %hours during the first 72 hours after birth. The secondary outcomes are brain activity on an amplitude-integrated electroencephalogram (aEEG), blood biomarkers (brain fatty acid binding protein (BFABP), neuroketal, and S100β), serious adverse reactions (SARs), severe brain injury, and all cause mortality at term date (approximately three months after birth). The exploratory outcomes are burden of hypoxia, burden of hyperoxia, neonatal morbidities, brain injury score on magnetic resonance imaging (MRI), number of therapies implemented during the intervention, physiological variables (mean blood pressure (BP), pulse oximeter oxygen saturation (SpO2), and partial pressure of carbon dioxide (pCO2)), and psychomotor impairment according to neurodevelopmental scales at 24 months after term date.