Oxygen deprivation at birth is known to set off processes that can lead to the death of brain cells and permanent neurological damage. Cooling the babies interrupts these processes to reduce brain injury.
An Oxford University and Imperial College London study found that 51.7% of oxygen-deprived babies treated with hypothermia survived to age 6–7 years with a normal IQ, compared to 39.4% of those who just received standard care.
Improved Motor Functioning
Cooling significantly reduced the chance of the 6 and 7 year-olds suffering from cerebral palsy and other moderate/severe disabilities. The children also showed improved motor functioning.
There was no difference in mortality rate between the standard care and hypothermia-treated groups, at around 30% of the children enrolled in the trial.
The TOBY clinical trial was funded by the Medical Research Council (MRC) and is the largest study of its kind. Its findings are published in the New England Journal of Medicine.
Brenda Strohm, research nurse and TOBY trial coordinator at the National Perinatal Epidemiology Unit, University of Oxford:
“We are indebted to all the families who took part in the TOBY Trial and then the TOBY Children Study; their contribution to these two important studies has made a real difference to neonatal care.
While corresponding with the families over the years, I have shared many happy stories of achievement and success as well as moments of sadness and loss; this is a privilege which adds a special dimension to my role of study co-ordinator. Thanks to our latest research, now when a baby is treated with cooling, families can be more fully informed about what might lie ahead, not only in the coming months but in the next few years too."
The trial involved 325 newborn babies that suffered from a lack of oxygen at birth.
They were randomly assigned into two groups within six hours of delivery, and either treated with standard care or standard care plus hypothermia, when their body temperature was reduced to 33.5˚C for 72 hours. After that time, they were slowly returned to a normal body temperature of 37˚C.
The new research reported today from the TOBY Children Study looked at whether there were any differences in the health of the children in later life.
Previously cooling had been shown to improve babies’ outcomes at 18 months. The new findings are important because they demonstrate that the improvements observed in brain function are not just temporary.
Hypothermia treatment has been endorsed by the National Institute for Health and Care Excellence (NICE) and adopted into clinical practice in the NHS. It has the advantage of being relatively simple and inexpensive to carry out. Lead author Professor Denis Azzopardi of King’s College London said:
‘This study is important as it confirms improved brain function persisting into middle childhood with cooling treatment, and it is a proof of the concept that treatment following oxygen deprivation at birth can be effective."
Hugh Perry, chair of the MRC Neurosciences and Mental Health Board, said:
“This study is a great example of how research can change people’s lives. Although major advances have been made in how childbirth is managed, approximately 2 out of every 1,000 newborn infants suffer from a lack of oxygen around the time of birth. Prior to the introduction of cooling therapy there were no approved, specific treatments that reduced the risk of brain injury long-term following asphyxia."
Effects of Hypothermia for Perinatal Asphyxia on Childhood Outcomes. Azzopardi D, Strohm B, Marlow N, Brocklehurst P, Deierl A, Eddama O, Goodwin J, Halliday H, Juszczak E, Kapellou O, Levene M, Linsell L, Omar O, Thoresen M, Tusor N, Whitelaw A, Edwards AD for the TOBY Study Group NEJM 2014; 371:140-9. DOI: 10.1056/NEJMoa1315788