RecruitingPhase IIInterventional

Carbogen for status epilepticus in children trial

An epileptic seizure that does not stop on its own is an emergency known as status epilepticus. It needs quick medical treatment to prevent brain harm. Currently, doctors give emergency medicines while the child breathes 100% oxygen through a face mask. Researchers want to find out if adding a small amount of carbon dioxide to oxygen (a mixture called Carbogen) works better. This gas mixture makes the brain very slightly more acidic, which may help calm electrical activity and stop the seizure faster. In this study, children brought to participating emergency departments with prolonged seizures will receive normal emergency drugs plus either standard oxygen or Carbogen. Because treatment must start immediately, doctors provide the gas straight away and ask parents for consent afterwards. This trial hopes to find a safer, faster way to stop severe childhood seizures.

At a glance

Status

Recruiting

Phase

Phase II

Sponsor

The Newcastle upon Tyne Hospitals NHS Foundation Trust

Enrolment target

424

Start

01 Nov 2022

Estimated completion

31 Oct 2026

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

What is this study about?

An epileptic seizure that carries on without stopping is a medical emergency called convulsive status epilepticus. The longer a seizure lasts, the higher the risk of complications and harm to the brain. Emergency teams must act quickly to calm the brain's electrical signals and protect the child.

Standard emergency care involves giving medicines through a vein or into the mouth, alongside pure oxygen through a face mask. Scientists believe that making the brain environment slightly more acidic can help switch off seizures sooner. A simple, gentle way to do this is by adding a tiny amount (5%) of carbon dioxide to oxygen. This gas blend is called Carbogen.

The CRESCENT trial compares Carbogen with standard oxygen to see if it helps stop seizures more quickly. Unlike many standard emergency drugs that make children very drowsy, Carbogen does not cause sleepiness and may even support natural breathing. By finding out whether Carbogen is safe and helpful, researchers hope to improve emergency seizure care for children across the NHS.

Key takeaways

The trial tests whether Carbogen gas stops severe seizures in children faster than pure oxygen.
Carbogen is given through a normal face mask alongside all standard emergency medications.
Because it is a medical emergency, consent is discussed with parents after the child is treated.
The study involves no extra needles, tests, or hospital appointments.
Parents can withdraw their child's data at any point without changing their care.

Who may be eligible?

This trial is for babies, children, and young people who arrive at a participating NHS emergency department with a serious seizure that is not stopping on its own. The treating doctor must decide that emergency rescue medicine is urgently needed to halt the seizure.

Children cannot take part if they have a specific condition called infantile spasms (West syndrome), or if their seizure is a non-epileptic attack rather than epilepsy. It is also not suitable for children who have already received second-stage seizure medicines (such as phenytoin, levetiracetam, or sodium valproate) during this same seizure episode, or those who have previously taken part in this study.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

The child arrives at a participating emergency department with an ongoing seizure.
The emergency doctor decides urgent medication is needed to stop the seizure.
The seizure is an epileptic convulsion, not a non-epileptic attack.
The child does not have infantile spasms (West syndrome).
The child has not already received second-stage seizure drugs during this episode.

Answer every question to see your result.

What does participation involve?

Taking part happens entirely in the hospital emergency department. Because treatment cannot be delayed, a computer randomly chooses whether the child receives standard oxygen or Carbogen through a face mask. Both groups receive all their usual emergency seizure medicines as normal.

There are no extra hospital visits, needles, or blood tests for the trial. Once the emergency is under control, the medical team will talk to the parents to explain the study and ask for permission to use the child's hospital records. The research team then tracks the child's recovery using notes from their normal hospital stay.

Potential risks and benefits

Carbogen may help stop seizures more quickly and can stimulate normal breathing, which is helpful because many standard seizure drugs cause drowsiness. The physical risks of taking part are very low because inhaling Carbogen through a mask feels just like breathing normal oxygen. The tiny amount of carbon dioxide used is safe and causes changes no greater than holding your breath for a few seconds. Taking part is entirely voluntary. Parents have the complete right to say no or withdraw their child's data at any time, and this decision will never affect the care their child receives.

Locations (12)

The Royal Victoria Infirmary and Associated Hospitals NHS Trust
City only
Newcastle upon Tyne, England
South Tyneside and Sunderland NHS Foundation Trust
City only
Sunderland, England
Bristol Royal Hospital for Children
Approximate
Bristol, England
Alder Hey Children's Hospital
Approximate
Liverpool, England
Royal Alexandra Children's Hospital
City only
Brighton, England
Nottingham University Hospitals NHS Trust - Queen's Medical Centre Campus
Unverified
Nottingham, England
Leeds General Infirmary
Unverified
Leeds, England
Barts Health NHS Trust
Unverified
London, England
University Hospitals of Leicester NHS Trust
Unverified
Leicester, England
University Hospitals of Derby and Burton NHS Foundation Trust
Unverified
Derby, England
The Royal Wolverhampton NHS Trust
Unverified
Wolverhampton, England
University Hospital Southampton NHS Foundation Trust
Unverified
Southampton, England

Common questions

Why wasn't I asked for permission before the trial started?

When a child has a severe seizure, doctors must act within seconds. Pausing to read forms could cause dangerous delays. Giving treatment first and asking parents afterwards is called 'deferred consent' and keeps the child safe.

Is Carbogen safe for my child to breathe?

Yes. Carbogen contains 95% oxygen—far more than room air—and only 5% carbon dioxide, which is about the same amount of carbon dioxide our bodies breathe out naturally.

Will my child still receive their standard medicines?

Yes. Every child receives the full standard emergency medical care recommended by NHS guidelines. Carbogen is given alongside normal treatment, never instead of it.

What happens if I do not want my child to be in the study?

You can tell the doctors you do not wish to take part when they speak to you. Your child's care will not be affected in any way, and their information will not be kept for the trial.

Are there any extra tests or clinic visits?

No. There are no extra blood tests, scans, or hospital visits. The research team will only look at the notes already written during your child's hospital stay.

How to find out more

CRESCENT Trial Team

crescent-trial@liverpool.ac.uk - Official trial record

Always speak to your GP or specialist before deciding to take part in a study.