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Contact Information:

Dr Rob Forsyth
-
crescent-trial@liverpool.ac.uk


Dr Rob Forsyth
-
crescent-trial@liverpool.ac.uk


Dr CRESCENT Trial Team
-
crescent-trial@liverpool.ac.uk


More information about this study, what is involved and how to take part can be found on the study website.

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Be Part of Research - Trial Details - Carbogen for status epilepticus in children trial
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Carbogen for status epilepticus in children trial

Recruiting

Open to: All Genders

Age: Child

Nottingham Leicester Leeds Newcastle upon Tyne Birmingham London Wolverhampton Derby Liverpool Bristol Sunderland Brighton

Medical Conditions

Severe epileptic seizures in children that are not stopping by themselves and require emergency medication to stop them

This information is provided directly by researchers, and we recognise that it isn't always easy to understand. We are working with researchers to improve the accessibility of this information. In some summaries, you may come across links to external websites. These websites will have more information to help you better understand the study.


An epileptic seizure that is not stopping is a medical emergency. The longer it lasts the greater the risk of brain damage or even, occasionally, death. We need better ways to stop long seizures sooner. We believe creating a slightly more acidic environment within the brain may help this. One convenient and safe way to alter brain acidity is to give someone a different gas mixture to breathe. Our bodies take oxygen out of the air we breathe in; we then breathe out carbon dioxide as a “waste” gas. Carbon dioxide is very slightly acidic: if you mix a small amount (5%) with oxygen it makes the body and brain slightly acidic. This mixture is called Carbogen. It still has much more oxygen in it than room air (95% compared to 21%), and only the same amount of carbon dioxide as in the air we normally breathe out.

Start dates may differ between countries and research sites. The research team are responsible for keeping the information up-to-date.  

The recruitment start and end dates are as follows:

01 Nov 2022 31 Aug 2025

Publications

2024 Protocol article in https://pubmed.ncbi.nlm.nih.gov/38812049/ (added 30/05/2024)

Half the children will receive standard drug treatment whilst breathing 100% oxygen (which is what happens currently) and the other half will receive standard drug treatment whilst inhaling Carbogen. The choice of whether a child is given Oxygen or Carbogen will be random. All children will receive the same standard medical drug treatment for their seizure.
Because this is an emergency situation, there isn’t time to give children's families information about the trial or ask if they wish to take part before the treatment is given. Families will be told that their child was in the trial and will be asked for their consent to remain in the study. This is known as “deferred consent”. We have recently successfully completed a trial of another treatment of ongoing seizures this way and found families understood and accepted this.


Children with ongoing seizures.

You can take part if:



You may not be able to take part if:


1. Known to have been previously enrolled in CRESCENT2. Infantile spasms (West Syndrome)3. Non-epileptic seizure (“pseudo status epilepticus”)4. Tonic posturing due to suspected brain herniation5. Has received phenytoin, levetiracetam, phenobarbital or valproate as part of the management of this episode of status epilepticus


Below are the locations for where you can take part in the trial. Please note that not all sites may be open.

  • Nottingham University Hospitals NHS Trust - Queen's Medical Centre Campus
    Nottingham University Hospital Derby Road
    Nottingham
    NG7 2UH
  • University Hospitals of Leicester NHS Trust
    Leicester Royal Infirmary Infirmary Square
    Leicester
    LE1 5WW
  • Leeds General Infirmary
    Great George Street
    Leeds
    LS1 3EX
  • The Royal Victoria Infirmary and Associated Hospitals NHS Trust
    Queen Victoria Road
    Newcastle upon Tyne
    NE1 4LP
  • Birmingham Women's and Children's NHS Foundation Trust
    Steelhouse Lane
    Birmingham
    B4 6NH
  • Barts Health NHS Trust
    The Royal London Hospital 80 Newark Street
    London
    E1 2ES
  • The Royal Wolverhampton NHS Trust
    New Cross Hospital Wolverhampton Road Heath Town
    Wolverhampton
    WV10 0QP
  • University Hospitals of Derby and Burton NHS Foundation Trust
    Royal Derby Hospital Uttoxeter Road
    Derby
    DE22 3NE
  • Alder Hey Children's Hospital
    Eaton Road West Derby
    Liverpool
    L12 2AP
  • Bristol Royal Hospital for Children
    Paul O'Gorman Building Upper Maudlin Street St Michael's Hill
    Bristol
    BS2 8BJ
  • South Tyneside and Sunderland NHS Foundation Trust
    Sunderland Royal Hospital Kayll Road
    Sunderland
    SR4 7TP
  • Royal Alexandra Children's Hospital
    Eastern Road
    Brighton
    BN2 5BE

Benefits:
As most medicines used in the treatment of Chronic Status Epilepticus (CSE) have sedating (induces a state of calm or sleep) or anaesthetic (reduces sensitivity to pain) properties, breathing complications are common. In contrast, Carbogen is non-sedating, and may actually act to stimulate breathing. The effects of Carbogen are potentially both rapidly acting and rapidly reversible. Whilst there has been no long-term benefit currently observed in the use of Carbogen in preventing seizures from occurring in the future, use of Carbogen during an ongoing seizure may help to stop the seizure quicker.
The direct burden of participation will be minimal. The experience of the trial intervention is identical to standard care (inhaling a medical gas via facemask alongside standard medical care). Since by definition children are in an ongoing seizure their awareness of involvement will be very limited if any. There are no additional visits, blood tests or other investigations arising from trial participation beyond standard care: all follow-up is based on data extraction from hospital notes.
Inhalation of much higher proportions of carbon dioxide in air than are being used here (20-30%) in awake volunteers causes a distressing sense of panic and “air hunger” that rapidly and immediately ends upon discontinuation. However we and others have shown that inhalation of 5% carbon dioxide is well tolerated by awake children. Again because these children are in a seizure they are unlikely to have any subjective sense of breathlessness.
Increasing the proportion of carbon dioxide in inhaled air will cause very slight increases in blood flow and pressure in the brain: they are equivalent to those that occur if someone holds their breath, which causes carbon dioxide levels in the blood to rise by similar amounts. They are dwarfed by the effects on blood flow and pressure of the seizure itself.
There are two conditions that in an emergency setting are sometimes mistaken for and treated as prolonged epileptic seizures: these are (i) non-epileptic attack disorder (NEAD) where someone erroneously believes they are having a seizure and imitates its features, sometimes as a result of emotional or psychological distress and (ii) a rare situation where critically ill unconscious patients can exhibit unusual sustained stiff postures.
Treating the NEAD group for epileptic seizures is not inherently dangerous but exposes patients to medications and procedures unnecessarily and potentially entrenches an erroneous diagnosis of epilepsy. Treating the second group for epileptic seizures can be harmful because in general causing further sedation and depressing breathing effort (which is a common side effect of medications for epilepsy) can make this situation worse. We have carefully considered any possible additional risk to patients in this second group from receiving carbogen (i.e. any additional risk from being in the active rather than the treatment-as-usual arm of the trial) and believe these are acceptable. However we have incorporated specific training for participating sites to make them aware of these two conditions and to improve diagnostic assessment skills in this difficult, emergency situation. Generally this second condition is not hard to suspect or diagnosis: the issue is awareness of the existence of the phenomenon. By offering specific site training we will be improving care for this rare clinical situation generally.
For parents there may be some anxiety resulting from the deferred consent model and the retrospective discovery of their child's participation in a trial where they may have received a novel therapy. However, experience from our previous trial (ECLIPSE), suggests this is not a major issue particularly where treatment has clearly been successful and the seizure terminated. In ECLIPSE, one of 286 children enrolled died due to complications of convulsive status epilepticus. We have had PPI help in preparing specific material informing the family of a child who has died about the trial.

Dr CRESCENT Trial Team
-
crescent-trial@liverpool.ac.uk


Dr Rob Forsyth
-
crescent-trial@liverpool.ac.uk


Dr Rob Forsyth
-
crescent-trial@liverpool.ac.uk



More information about this study, what is involved and how to take part can be found on the study website.


The study is sponsored by The Newcastle upon Tyne Hospitals NHS Foundation Trust and funded by National Institute for Health Research Efficacy and Mechanism Evaluation Programme; National Institute for Health Research.



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Read full details for Trial ID: ISRCTN52731862

Or CPMS 52343

Last updated 15 August 2024

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