Alleman BW, Bell EF, Li L, Dagle JM, Smith PB, Ambalavanan N, et al. Individual and Center-Level Factors Affecting Mortality Among Extremely Low Birth Weight Infants. Pediatrics. 2013. This paper from the NICHD network shows substantial variation in survival between network hospitals for babies weighing under 1 kg. Let’s focus on the group with the highest mortality, below 25 weeks gestation. The authors examined differences in the risk characteristics of the babies and found that there were some differences, but when correcting for these risk factors there remained major differences between hospitals. They then examined how actively the hospitals intervened for each infant. They created an intervention score which included 11 different interventions that might be needed in the first day of life, and another 4 which are usually used later on.
If we first look at individual components of that score we can see enormous variation in their use between hospitals. Tracheal intubation for example was used for between 24% and 94% of the extremely preterm infants. 10% to 63% of them were delivered by cesarean. The results of this study show that the infants who had more interventions had lower early mortality (in the first 12 hours of life) and lower overall mortality prior to discharge. It seems that the willingness to provide interventions around birth, and to provide intensive care after birth leads to more babies surviving. The intervention score is one way of looking at this of course, but the problem with the score is that some items are ways to improve survival (antenatal steroids, NICU admission) and some are responses to serious illness, such as high frequency ventilation. Which is like putting apples and oranges into an overall fruit score. Nevertheless it does show that if you want to provide intensive care to extremely preterm infants with the best chance of success, you should be prepared to do intensive care.
Ruth Guinsberg has done a lot of great work in Brazil, in this new study she and the Brazilian Neonatal Network published the results of first day survival of 23 to 26 week gestation infants. (Guinsburg R, de Almeida MFB, Sadeck LDR, Marba STM, Rugolo LMSD, Luz JH, et al. Proactive management of extreme prematurity: disagreement between obstetricians and neonatologists. Journal of Perinatology. 2012;32(12):913-9) They examined whether the infants had at least one dose of steroids at some point prior to delivery or whether they were delivered by cesarean. If either were present it was considered active obstetric intervention. Then then looked at whether there was active intervention after delivery. They found that babies who were actively treated in the NICU despite not having active obstetric intervention had 3 times higher mortality than when both obstetrics and neonatology provided active care. This study has some of the limitations of all data base studies, you don’t know why certain interventions were given in an individual case, and the characteristics of the cases were different at baseline, but it is suggestive, and makes a lot of common sense. If you are prepared to give intensive care to extremely preterm babies, then the obstetrics team needs to be on-side, and a joint approach is required, with decisions made by the parents with both teams of caregivers.