Effect of Hyperbaric Oxygen Therapy on Microcirculation (MICROHB)

University Hospital, Lille

Status: Completed

Conditions: Hyperbaric Oxygen Therapy

Treatments: Procedure: Hyperbaric oxygen therapy

Study type: Interventional

Funder types: Other

Identifiers

NCT03980210

2019-A00053-54 (Registry Identifier)

2018_63

Details and patient eligibility

About

Previous studies shoes that hyperoxia alters microcirculation.The investigators hypothesize that hyperbaric may restore microcirculation integrity. This hypothesis is supported by a recent study in rabbits, but no data exists for humans.

The study will expose fifteen healthy volunteers to a succession of different fraction of inspired oxygen and barometric pressure and assess microcirculatory and macrocirculatory changes via sidestream dark field videomicroscopy, near-infrared spectroscopy, Laser Doppler, transthoracic echocardiography and bio-impedancemetry at every step.

Full description

Microcirculation alterations and hyperoxia are known to alter ICU-patients' prognostic.

Studies have shown that hyperoxia alters healthy volunteers' microcirculation, whereas hyperbaric oxygen therapy is commonly used to facilitate cicatrization. There seems to be a paradox. A recent study in rabbits has given some evidences that hyperbaria may restore microcirculation integrity, but to date, there is no such evidences in human.

To study hyperoxia and hyperbaric induced changes in micro and macrocirculation, fifteen healthy volunteers will be exposed to successive variations of inspired oxygen fraction and barometric pressure according to a predefine sequence so that only one parameter will change from a condition to the next one :

1. FiO2 0.21 - 1 ATA
2. FiO2 1 - 1 ATA
3. FiO2 1 - 2.5 ATA
4. FiO2 0.21 - 2.5 ATA
5. FiO2 0.21 - 1 ATA

At each time, and after a 30 minutes period of exposure, measures will be made using SDF-microscopy, Laser Doppler and NIRS to assess microcirculation.

As previously described, macrocirculation can modify microcirculation due to a mechanism called hemodynamic coherence.

Hence, the investigators planned to assess macrocirculation changes at every step of the protocol using bioimpedancemetry and transthoracic echocardiography.

Each volunteer will be his own control, using the first measurements (condition 1. FiO2 0.21 - 1 ATA) as reference.

Enrollment: 15 patients

Sex: All

Ages: 18 to 64 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• To provide a medical certificate of fitness to dive (< 1 year)
• Consent given for study participation
• French health insurance affiliated

Exclusion criteria

• Temporary or definitive contra-indication to dive
• Pregnancy or < 18 years of age
• Precedent dive < 24 hours
• Under a legal protection measure
• Medical history of a disease known to alter microcirculation

Trial design

Primary purpose: Basic Science

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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15 participants in 1 patient group

Hyperbaric oxygen therapy

Experimental group

Description:

Successive changes in fraction of inspired oxygen and barometric pressure (ATA: Atmosphere absolute) Five successive steps: 1. FiO2 0.21 - 1 ATA 2. FiO2 1 - 1 ATA 3. FiO2 1 - 2.5 ATA 4. FiO2 0.21 - 2.5 ATA 5. FiO2 0.21 - 1 ATA

Treatment:

Procedure: Hyperbaric oxygen therapy