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Seizure control via pH manipulation: a phaseII double-blind randomised controlled trialof inhaled carbogen as adjunctive treatmentof paediatric convulsive status epilepticus (Carbogen for Status Epilepticus in Children Trial (CRESCENT ))

Lookup NU author(s): Dr Rob ForsythORCiD, Dr Niall Mullen, Dr Jason Urron



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Background: Paediatric convulsive status epilepticus is the most common neurological emergency presentingto emergency departments. Risks of resultant neurological morbidity and mortality increase with seizure duration.If the seizure fails to stop within defined time‐windows, standard care follows an algorithm of stepwise escalationto more intensive treatments, ultimately resorting to induction of general anaesthesia and ventilation. Additionally, ventilatory support may also be required to treat respiratory depression, a common unwanted effect of treatment. There is strong pre‐clinical evidence that pH (acid–base balance) is an important determinant of seizure commencement and cessation, with seizures tending to start under alkaline conditions and terminate under acidic conditions. These mechanisms may be particularly important in febrile status epilepticus: prolonged fever‐related seizures which predominantly affect very young children. This trial will assess whether imposition of mild respiratory acidosis by manipulation of inhaled medical gas improves response rates to first‐line medical treatment. Methods: A double‐blind, placebo‐controlled trial of pH manipulation as an adjunct to standard medical treatment of convulsive status epilepticus in children. The control arm receives standard medical management whilst inhaling 100% oxygen; the active arm receives standard medical management whilst inhaling a commercially available mix‐ ture of 95% oxygen, 5% carbon dioxide known as ‘carbogen’. Due to the urgent need to treat the seizure, deferred consent is used.

Publication metadata

Author(s): Forsyth R, Allen M, Bedson E, Downes A, Gough C, Hartshorn S, Lawton K, Lyttle MD, Messahel S, Mullen N, Raper J, Rosala-Harris A, Taggart L, Urron J, Walton E, Gamble C

Publication type: Article

Publication status: Published

Journal: Trials

Year: 2024

Volume: 25

Online publication date: 29/05/2024

Acceptance date: 17/05/2024

Date deposited: 30/05/2024

ISSN (electronic): 1745-6215

Publisher: BioMed Central Ltd


DOI: 10.1186/s13063-024-08188-5


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Funder referenceFunder name
Efficacy and Mechanism Evaluation (EME) Programme