Babies who have received insufficient oxygen during birth are at risk of suffering brain damage. If an injury is evident on neuroimaging, its form may reflect whether the injuring hypoxic event was acute and severe or prolonged and intermittent/partial in nature.
In the neonatal period, babies suffering such injuries are often diagnosed with hypoxic ischaemic encephalopathy (HIE), with a need for resuscitation after birth: they may exhibit neurological depression, seizures and electroencephalographic abnormalities. Treatment has traditionally been aimed at supporting babies during the neonatal period and providing medication to treat any seizures. There is a significant risk of such babies dying or subsequently being diagnosed with cerebral palsy, a neurological disorder that primarily affects body movement and muscle coordination.
Over the last 20 years, trials have been conducted to assess whether babies who are thought to have suffered brain injury due to a lack of oxygen at birth benefit from being cooled in a controlled manner for a period of two to three days after birth. The aim of this treatment is to slow down the processes that cause brain damage - the technical name is therapeutic hypothermia with intracorporeal temperature monitoring for hypoxic perinatal brain injury. Babies undergoing this treatment have their temperatures reduced from 37 degrees to between 33 and 35 degrees using a special mattress or head cap. Once the period of cooling is complete, their internal temperature is then gradually returned to normal.
The National Institute for Health and Care Excellence (NICE) initially issued guidance in relation to this treatment in May 2010, noting that research had indicated that therapeutic hypothermia reduced the risk of death and the diagnosis of cerebral palsy when compared with standard neonatal care only. Since this advice, therapeutic hypothermia has become widely used in neonatal units set up to provide such treatment.
However, while the treatment does appear to impact survival rates positively and reduce the severity of mobility problems that might be expected after a significant hypoxic brain injury, more recent research suggests that there may be some significant limitations to the treatment.  It has been shown that school age children without a diagnosis of cerebral palsy, who were cooled for HIE, have reduced cognitive and motor performance and increased emotional difficulties compared to their peers. It cannot be assumed that those children, who initially appear to be developing well despite suffering perinatal hypoxic injuries, will not have some difficulties in the future.
Alison Appelboam Meadows, a partner in the clinical negligence team at Penningtons Manches Cooper, who acts on behalf of children that have sustained brain injuries during birth, comments: “It is becoming clear that some children who have been diagnosed with HIE and then therapeutically cooled after birth appear to have met their major developmental milestones in their early years. However, when these same children start school, they are then found to have cognitive and behavioural difficulties.
“While cooling may limit the impact of a hypoxic injury on a child’s mobility and coordination, it may not prevent the full cognitive and behavioural impact of the injury. It is therefore important that a comprehensive assessment of a child’s condition is undertaken at an appropriate stage of their development to ensure that they are adequately compensated for any avoidable injuries they may have sustained.”
 School-age outcomes of children without cerebral palsy cooled for neonatal hypoxic-ischaemic encephalopathy in 2008 – 2010 by Lee-Kelland R et al Arch Dis Child Fetal Neonatal Ed 2019