Could cooling treatment help babies born with mild HIE? An important research study may have the answer
As a clinical negligence solicitor specialising in child brain injury, I spend a great deal of time thinking about hypoxic ischaemic encephalopathy (HIE). I have represented many children and families whose lives have been shaped by this devastating condition, and I have seen firsthand the lasting impact it can have, even in cases that were initially considered “mild.”
It is therefore with interest that I will be following the COMET trial – a major research study funded by the National Institute for Health and Care Research that could change the way mild HIE is treated in this country.
What is HIE, and why does “mild” matter?
HIE is a condition that occurs when a baby’s brain is deprived of oxygen and blood supply around the time of birth. It can cause injury to the brain, and it is graded as mild (Grade I), moderate (Grade II) and severe (Grade III).
Mild HIE has long been treated as being at the less serious end of the spectrum. Babies with mild HIE are often irritable, have difficulties with breathing and feeding, and need a short period of care in a neonatal intensive care unit – but they tend to improve within a few days and go home. Parents are often reassured. On the surface, these babies appear to recover.
But as those of us working with families affected by HIE know, the picture is far more complicated than that. Research increasingly shows that children born with mild HIE face lasting cognitive and neurological challenges that only become fully apparent as they grow. In the UK, approximately 800 babies per year are admitted to neonatal units with mild HIE. Many of these babies have lower cognitive scores at two years of age compared to their peers, and 38% require special education support (Cooling in Mild Encephalopathy Trial (COMET) – NIHR Funding and Awards). These children may not have cerebral palsy or obvious physical disabilities, but they can face real, lifelong difficulties with learning and development that affect their quality of life and their futures in profound ways.
The treatment gap
It is now standard NHS practice for babies diagnosed with moderate or severe HIE to be offered a well-established, evidence-based treatment: therapeutic cooling, also called therapeutic hypothermia. Within six hours of birth, a baby’s body temperature is carefully reduced to 33.5°C and maintained for 72 hours. This slows the cascade of cell death in the brain and has been shown conclusively to reduce death and serious disability.
However, babies with mild HIE have, until now, been excluded from this treatment under current NICE guidelines because there has not been the evidence to support or rule out its use in this group.
Despite this, some NHS hospitals have begun offering cooling to babies with mild HIE anyway. The result is a postcode lottery: some babies with mild HIE receive cooling, others do not, and nobody really knows whether it is helping or harming.
The COMET trial: filling the evidence gap
This is where the COMET trial comes in. COMET – which stands for Cooling in Mild Encephalopathy Trial – is a multicentre, randomised controlled study funded by the National Institute for Health and Care Research (NIHR). It is led by Imperial College London and is one of the most significant pieces of research in this field in a generation.
The trial is asking a straightforward but critically important question: Does whole-body cooling safely improve cognitive outcomes in babies with mild HIE?
To answer it, researchers are recruiting 426 babies born at 36 weeks or later across 60 NHS hospitals over a two-and-a-half-year period. Half will be randomly chosen to receive cooling therapy (body temperature maintained at 33.5°C) initiated within six hours of birth and continued for 72 hours; the other half will be kept at normal temperature (37°C). Both groups will receive otherwise identical specialist neonatal intensive care. All babies will have an MRI scan before going home, and at two years of age, a specially trained clinician will assess each baby’s cognitive development.
Parents are also being asked to consent to their babies being assessed at school age, subject to future funding, which could give us data on longer-term outcomes that would be enormously valuable.
Importantly, the trial will also assess cost-effectiveness. If cooling is found to be safe and beneficial, the researchers will make the financial case for rolling it out to all babies with mild HIE across the NHS. If it is found to be harmful or ineffective, that will end the practice in those hospitals currently offering it and provide clarity for the whole country. More information available here.
Why this matters
The COMET trial results will inform the basis of future NHS guidelines. But it also validates the concern that mild HIE is not as benign as it has sometimes been presented. It confirms that the medical and scientific community takes the risk of lasting harm from mild HIE seriously, and it confirms that the question of whether more could and should be done for these babies is one worth funding research to answer.
And for parents of babies yet to be born, the trial offers the genuine prospect of a new, evidence-based treatment that could protect their children’s cognitive futures.
What happens next?
The trial is currently recruiting participants at NHS hospitals across the UK. Results, including the primary cognitive outcome data at 24 months, are expected in the coming years. If the results are positive, we could see cooling therapy recommended for mild HIE – a significant change in neonatal care that would affect hundreds of families every year.
I will be watching the results of this trial closely. As someone who sees the very real challenges faced by children who were born with mild HIE and their families, I hope it provides the answers that could potentially help so many in the future.
If your child was born with HIE
If your child was born with HIE – whether mild, moderate or severe – and you have concerns about the care they received around the time of birth, I would encourage you to seek specialist legal advice. Clinical negligence claims arising from birth injuries are complex, and getting the right legal advice early on can make such a difference.
At BBK, our specialist child brain injury team acts exclusively for children and families affected by brain injury. We understand HIE and its long-term effects, and the questions families are often left with, long after discharge from hospital. If you would like to discuss your concerns with us, please do get in touch for a confidential, no-obligation conversation.
