title: It is possible to perform a double-blind hyperbaric session: a double-blinded randomized trial performed on healthy volunteers.
abstract: In hyperbaric medicine, blinded trials are remarkably few, making results susceptible to criticism. The scopes of the present study are to present a method for a double-blinded randomized clinical study and evaluate the validity of the method in a hyperbaric setting. Twenty-two healthy volunteers with no diving experience were included. The volunteers were randomized either to a "therapeutic pressure" group (15 msw, 253 kPa) or to a "placebo" group (2 msw, 120 kPa). The two profiles were made equal regarding noise, temperature and ventilation. The volunteers were asked whether they had been exposed to placebo or therapeutic pressure. They were asked to present their certainness of the answer on a visual analogue scale (VAS). Fisher's exact test calculates a probability of P = 0,328, which indicates that the volunteers have no valid opinion as to whether they were exposed to 15 msw or to 2 msw. It is found that it is possible to perform a blinded treatment on healthy volunteers with no prior diving experience.
authors.affiliation: The Hyperbaric Oxygen Treatment Unit, Department of Anesthesia and Operating Theater Services 4231, Center of Head and Orthopedics, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark.
authors.forename: T
authors.initials: T
authors.lastname: Jansen
authors.forename: C R
authors.initials: CR
authors.lastname: Mortensen
authors.forename: M F
authors.initials: MF
authors.lastname: Tvede
mesh_terms: D004311:Double-Blind Method; D005240:Feasibility Studies; D006801:Humans; D006931:Hyperbaric Oxygenation; D011312:Pressure