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Double-blind, placebo-controlled crossover trial of inhaled oxygen in the treatment of acute cluster headache
DOI 10.1186/ISRCTN94092997
ClinicalTrials.gov identifier
EudraCT number
Public title Double-blind, placebo-controlled crossover trial of inhaled oxygen in the treatment of acute cluster headache
Scientific title
Acronym CHAO2
Serial number at source CHO2
Study hypothesis Oxygen is a more effective treatment of acute cluster headache than air.
Lay summary
Ethics approval The National Hospital for Neurology and Neurosurgery, approved on 3 March 2003 (ref: 01/N122)
Study design Double-blind, placebo-controlled, cross-over randomised trial.
Countries of recruitment United Kingdom
Disease/condition/study domain Cluster headache
Participants - inclusion criteria 1. Active Cluster headache
2. Attack duration between 45 minutes and three hours
Participants - exclusion criteria 1. Pregnant and lactating women will be excluded
2. Patients with moderate to severe chronic obstructive pulmonary disease will be excluded as the high-dose high-flow oxygen may affect their hypoxic respiratory drive.
3. Patients who cannot tolerate the oxygen mask in the correct fitting will be excluded from the study
Anticipated start date 02/04/2003
Anticipated end date 30/04/2007
Status of trial Completed
Patient information material
Target number of participants 55
Interventions Treatment of acute cluster headache with inhaled air or oxygen. Each participant will be randomised to treatment sequence of either AB or BA, where A is oxygen and B is inhaled air.
Primary outcome measure(s) Proportion of patients pain free after 15 minutes of treatment comparing oxygen and air.
Secondary outcome measure(s) 1. Rendering the patient pain free at 30 minutes
2. Reduction in pain scale at 15, 30, 45 and 60 minutes
3. Need for rescue medication from 15 minutes after treatment
4. Overall response to the treatment and overall functional disability
5. Effect on associated symptoms
Sources of funding BOC Gases (International)
Trial website
Publications 2009 results in http://www.ncbi.nlm.nih.gov/pubmed/19996400
Contact name Prof  Peter  Goadsby
  Address Institute of Neurology
Queen Square
  City/town London
  Zip/Postcode WC1N 3BG
  Country United Kingdom
Sponsor BOC Ltd (UK)
  Address Chertsey Road
  City/town Surrey
  Zip/Postcode GU20
  Country United Kingdom
  Sponsor website: http://www.boc-gases.com/
Date applied 22/04/2007
Last edited 10/12/2009
Date ISRCTN assigned 15/06/2007
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