26 April 2013
Xenon gas successfully delivered to babies in ambulance
Two babies at risk of brain injury following a lack of oxygen at
birth have received xenon gas and cooling therapy while being
transferred from one hospital to another in a specially equipped
ambulance.
The first use of xenon gas and cooling in treating babies
deprived of oxygen at birth took place at St Michael's Hospital in
Bristol in 2010, but new technology now means that it can be
delivered to babies while they are being transferred to St
Michael's Hospital as part of a clinical trial.
The pioneering technique of delivering cooling and xenon gas to
babies has been developed by Marianne Thoresen, Professor of
Neonatal Neuroscience at the University of Bristol and Consultant
Neonatologist at St Michael's Hospital, Bristol and Dr John
Dingley, Consultant Anaesthetist and Reader in Anaesthetics at
Swansea University's College of Medicine. This trial is being
funded by the J P Moulton Charitable Foundation,SPARKS (Sport
Aiding Medical Research for Kids) and the Alumni foundation
University of Bristol.
In the UK, every year, more than 1,000 otherwise healthy babies
born at full term die or suffer brain injury caused by a lack of
oxygen and/or blood supply at birth. This can lead to lifelong
problems such as cerebral palsy and learning
difficulties.
Poppy Laker was the second baby in the world to receive xenon
while being transferred between hospitals. When she was born at the
Royal United Hospital in Bath she was not breathing and needed to
be resuscitated. Her parents were told about the xenon trial and
decided within 30 minutes to give permission for Poppy to take part
in the trial. She was randomised to receive xenon in addition to
the standard cooling therapy. Parents Stephen and Kelly Laker from
Somerset said that the baby was doing well and has been taken off
the ventilator after four days and all medication and now simply
has a feeding tube to help her eat.
Professor Marianne Thoresen says: "Xenon is a very rare
and chemically inert anaesthetic gas found in tiny quantities in
the air that we breathe. In 2003 Dr John Dingley and I realised the
potential xenon and cooling might have in combination to further
reduce disability. Over the past 10 years, we have shown in the
laboratory that xenon doubles the protective effect of cooling on
the brain.
"Previously babies would need to come to us at St Michael's
Hospital to have xenon gas treatment started, but we believe it is
essential to start the xenon therapy as soon as possible after
birth. As we work as part of a network, babies can come to us from
Taunton to Swindon to Gloucester and often babies can't get back to
us within five hours to start the treatment.
"Now, Dr Dingley has designed and built the equipment to
commence delivery of the xenon to babies while they are still at
the referring hospital and then while they are being transferred to
St Michael's Hospital. Hopefully this will mean that more babies
will have the opportunity to take part in the trial."
Dr Dingley has been developing equipment in Swansea for xenon
anaesthesia in adults and more recently babies for over 10 years.
His machine takes the exhaled gas, removes waste products from it
and re-circulates it to be breathed again without any loss to the
outside air.
Dr Dingley says: "To reduce delay between birth and
treatment it is now common to start cooling therapy during the
ambulance transfer and we wanted to do this with the xenon as well.
Therefore I developed a very compact version of the xenon breathing
system we are using in the baby unit that fits a small space on the
ambulance baby transport system so xenon can be delivered to the
lungs continuously even while the baby is being moved. The system
needs to recirculate all the breathed gases to contain costs as
xenon is extremely expensive."
St Michael's Hospital and the University of Bristol has
pioneered new treatments for brain injury in babies since Marianne
Thoresen first started cooling babies in 1998, showing that cooling
babies after a lack of oxygen could reduce damage in the newborn
brain. After her original laboratory work from 1995 showing that
cooling after lack of oxygen reduced brain injury in animal models,
clinical trials of cooling have now proven that mild cooling by
only a few degrees for 72 hours is a safe and beneficial treatment.
However, cooling only partially reduces disability and does not
prevent it in all babies. The search has been to find a second
treatment that could be added to cooling to further reduce
disability. From 2010 to 2011, for the first time in the world, 14
cooled infants at St Michael's Hospital took part in a study
examining whether xenon could be delivered safely and without side
effects. This was carried out successfully enabling ethical
approval for the current randomised study comparing xenon and
cooling with the standard of cooling therapy on its own.
So far, 17 babies have taken part in this randomised controlled
trial. Around half of them have had xenon and cooling and the other
half the standard cooling therapy. The plan is to recruit 84 babies
to the trial, the number predicted to be needed to show a
difference between the two groups if there is one.
J P Moulton Charitable Trust says: "It is very gratifying
to have part funded such exciting work. The team at Bristol
are both talented and exceptionally dedicated."
John Shanley, Chief Executive for Sparks, adds: "Each year
in the UK, over 3,500 babies die before their first
birthday. Funding research that helps prevent, diagnose, treat
and cure conditions affecting the health of children is at the
heart of what Sparks does. We have been committed to funding
research into xenon gas and cooling therapy for a number of years,
and we are pleased to start seeing the outcomes of the wonderful
work being done by Professor Thoresen and her team."
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