MNSI warns of rise in maternity safety referrals during COMET cooling trial for babies with mild HIE

Maternity safety watchdog, MNSI has warned hospitals of an expected increase in referrals to its maternity investigations programme whilst a trial of therapeutic cooling for newborn babies with mild hypoxic ischaemic encephalopathy (HIE) takes place across 40 NHS hospitals.

The findings of this important trial, known as the Cooling in Mild Encephalopathy Trial (COMET), could open the way for newborn babies with mild HIE birth injury to receive therapeutic cooling, a treatment only offered routinely to babies born with moderate or severe HIE.  

Alternatively, if neonatal cooling is found to be unsafe or ineffective in reducing mild HIE brain injury, steps may be taken to stop the current (informal) practise in many hospitals of offering cooling for babies with mild HIE birth injury, with an annual cost saving to the NHS of more than £5 million.

What is cooling?

Therapeutic hypothermia or ‘cooling’ is a treatment that is given to newborn babies who are born with moderate or severe HIE brain injury, to slow down the rate of damage to their brain. HIE or hypoxic ischaemic encephalopathy is caused by lack of oxygen. In the UK, around one in every 1,000 babies born each year suffer an HIE brain injury around the time of birth. Depending on its severity, their brain injury can lead to lifelong disability which, at best, can only be managed with regular therapies, specialist equipment and care. 

There is no cure for HIE brain injury, however, in recent years, treatment with therapeutic cooling has been found to reduce the permanent physical disability suffered by babies after a moderate or severe HIE birth injury. If correctly administered to an injured baby in the first few hours immediately after birth, controlled cooling can reduce swelling and pressure within the brain, slow down brain cell metabolism and repair brain cells, reducing the extent of the damage to the developing brain. This can prevent or significantly reduce the severe physical disability or cerebral palsy that would otherwise be expected from a moderate or severe HIE brain injury. After cooling, many children who were born with HIE brain injury are able to meet their early developmental milestones and are left with little or no obvious physical disability.

Following birth asphyxia or HIE birth injury, the physical-disability-reducing benefits of cooling are potentially so life-changing for the child that NICE guidance recommends cooling for all eligible newborn babies with moderate or severe HIE who are expected to survive, subject to the treatment being carried out in accordance with recognised safety criteria.

Cooling must take place in a specialist neonatal unit and must follow strict safety guidelines. This includes the neonatal care team explaining to the parents the benefits and risks of the treatment and obtaining their agreement for their child to receive it. Babies needing cooling should start their treatment as soon as possible and no later than six hours after birth. Their body temperature must be safely lowered and maintained at a temperature between 33.5° and 34.5°C for around three days. This is usually achieved by placing the baby on a fluid-cooled mattress, or by cooling their head with a special cap. After the cooling period, the baby’s temperature is gradually brought back up to normal temperature, in a process known as ‘rewarming’. The baby’s condition must be carefully monitored before, during and after their cooling treatment.

What is the COMET cooling trial?

The Cooling in Mild Encephalopathy Trial (COMET) is being funded by The National Institute for Health and Care Research (NIHR) and aims to assess the safety and effectiveness of therapeutic cooling as a treatment for babies with mild HIE brain injury.

In the UK, around 800 babies each year suffer mild HIE brain injury as a result of a lack of oxygen around the time of birth. Babies with mild HIE have symptoms of irritability, breathing and feeding difficulties, and need nursing on a neonatal intensive care unit (NNU, NICU or SCBU) for a few days after birth.  Their condition often improves and they are discharged home within a few days. Whilst most don’t suffer any obvious long-term, physical disability, many are found to have lower cognitive (thinking) skills at two years of age and lower IQ during their school years, compared with their peers. More than a third (38%) need support with special educational needs (SEN).

Whilst NICE guidance recommends therapeutic cooling as a treatment for babies with moderate or severe HIE birth injury owing to its proven benefits in reducing their physical disability, cooling is increasingly also being used in NHS hospitals for babies with mild HIE, without any proper evaluation of its safety or efficacy in treating the effects of their milder brain injury. Without the proven benefits of a potential significant reduction in physical disability, COMET asks whether the additional invasiveness and risks of cooling and neonatal intensive care to these more mildly injured children can be justified, compared to normal treatment without cooling.  The COMET trial was developed in response to a call from the British Association of Perinatal Medicine (BAPM) for urgent evaluation of the safety and efficacy of therapeutic hypothermia (cooling) in mild HIE.  COMET’s findings are expected to lead to rapid changes to the national guidelines, either to extend and standardise, or more firmly restrict the safe use of cooling.

Over a two-year period, some babies of 36 weeks or longer gestation, who are born in NHS hospitals with evidence of birth asphyxia and mild encephalopathy will, with their parents’ consent, be entered into the COMET trial and receive either normal treatment or cooling within six hours of birth. Their outcome, including their cognitive development at two years of age, will be measured and compared with babies who were randomly selected to not receive cooling in the trial.  If cooling therapy is found to be safe and beneficial, the COMET researchers say they will report this together with the costs when ‘making a financial case’ for this NHS treatment to be made available to all babies with mild HIE birth injury. If, however, cooling treatment in these circumstances is found to be harmful or in-effective, it will no longer be offered to babies with mild HIE, leading to an annual cost saving of at least £5 million to the NHS.

How will the COMET cooling trial affect MNSI referrals?

Maternity safety watchdog, MNSI, advises that all babies born at or after 37 weeks (but not 36) who were cooled as part of the COMET trial should be referred to MNSI. The MNSI team will review these babies’ clinical history and MRI scans to assess whether there is any evidence of hypoxic brain injury. As usual, MNSI will only carry out a full maternity safety investigation relating to the child’s injury if the MRI scan reveals a hypoxic brain injury and the family consents to share medical records with MNSI, or if concerns are raised by the parents or the NHS trust.

We await the COMET trial’s findings with interest, and welcome any resulting clarification to the national guidance on the safest and most life-enhancing treatment for these babies.

Where a child or teenager suffers from neurological injury or learning disability which was caused by a hypoxic brain injury (HIE) during birth or as a newborn baby, they may be entitled to substantial compensation.

If your child has cerebral palsy or neurological disability as a result of medical negligence or you have been contacted by HSSIB/MNSI or NHS Resolution, you can talk to a solicitor, free and confidentially, for advice about how to respond or make a claim by contacting us