Conditions: Traumatic Brain Injury
Keywords: Hyperbaric oxygen
Allocation: RANDOMIZED | Intervention model: SINGLE_GROUP
Enrollment: 42
Healthy volunteers: yes

Brief summary:
SCUBA divers and chamber inside attendants will undergo a brief hyperbaric chamber excursion and will be asked to what chamber pressure they were compressed and what gas they breathed.

Detailed description:
In clinical trials evaluating hyperbaric oxygen, blinding can be challenging. Options for participant blinding include offering regular air at a lower pressure than the hyperbaric oxygen intervention, or compressing all participants to the same pressure but providing different gas mixes to the active and sham arms.

In some trials of hyperbaric oxygen for brain injury, investigators offer a sham chamber session (regular air at 1.2 atmospheres absolute \[atm abs\]) compared to the active intervention, hyperbaric oxygen (100% oxygen at 1.5 atm abs). It is unknown whether individuals familiar with pressure changes, such as divers and hyperbaric chamber inside attendants, could discern the difference between these pressures and thereby become unblinded to study allocation.

In this study, 80 experienced divers and chamber inside attendants will be enrolled and randomly assigned to one of four possible chamber pressures and one of two breathing gases. After a brief hyperbaric chamber excursion, they will be asked to what chamber pressure they were compressed and what gas they breathed. If participants can accurately report chamber pressure or breathing gas, pressure-familiar individuals should be excluded from blinded clinical trials of hyperbaric oxygen.

Arms:
arm 1: Sham Chamber Session

Sea Level Equivalent 1.2 atm abs (2.6 psig) breathing regular air 20-chamber excursion arm 2: Hyperbaric Oxygen (1.5 atm abs)

Sea Level Equivalent 1.5 atm abs (6.2 psig) breathing 100% oxygen 20-minute chamber excursion arm 3: Sham Chamber Session

Altitude Equivalent 1.2 atm abs (5.1 psig) breathing regular air 20-minute chamber excursion arm 4: Hyperbaric Oxygen (1.5 atm abs)

Altitude Equivalent 1.5 atm abs (9.6 psig) breathing 100% oxygen 20-minute chamber excursion

Interventions: intervention 1: Hyperbaric Oxygen (1.5 atm abs) intervention 2: Sham Chamber Session
Intervention descriptions: intervention 1: Hyperbaric oxygen (100% oxygen) delivered at a chamber pressure of 1.5 atm abs. intervention 2: Sham control chamber session: regular air delivered at a chamber pressure of 1.2 atm abs

Protocol document: