Clinical trial NCT03980210: Effect of Hyperbaric Oxygen Therapy on Microcirculation
Official title: Effect of Hyperbaric Oxygen Therapy on Healthy Volunteers Microcirculation
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Hyperbaric Oxygen Therapy
Keywords: Hyperbaric oxygen therapy
Normobaric oxygen therapy
Hyperoxia
Sidestream dark field videomicroscopy
Microcirculation
Lead sponsor: University Hospital, Lille
Sponsor class: OTHER
First posted: 2019-06-10
Enrollment: 15
Sex: ALL
Minimum age (years): 18
Maximum age (years): 64
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: BASIC_SCIENCE

Brief summary: 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.

Detailed 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.

Eligibility criteria: 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

Primary outcomes:
measure: Changes in proportion of perfused vessel (PPV)
timeFrame: 30 minutes after hyperbaric hyperoxia exposure (FiO2 1 - 2.5 ATA)
Secondary outcomes:
measure: Changes in proportion of perfused vessel (PPV)
timeFrame: 30 minutes after FiO2 1 - 1 ATA exposure
measure: Changes in proportion of perfused vessel (PPV)
timeFrame: 30 minutes after FiO2 0.21 - 2.5 ATA exposure
measure: Changes in hyperemic reaction after a vaso-occlusion test
timeFrame: 30 minutes after FiO2 1 - 2.5 ATA exposure
measure: Changes in area of hyperaemia after a vaso-occlusion test
timeFrame: 30 minutes after FiO2 1 - 2.5 ATA exposure
measure: Validation of cardiac output assessed by bioimpedancemetry under hyperbaric condition
timeFrame: 30 minutes after FiO2 1 - 2.5 ATA exposure
Other outcomes:
Locations:
city: Lille
country: France
facility: Hôpital Roger Salengro, CHU
Study officials:
affiliation: University Hospital, Lille
name: Thibault Duburcq, MD
role: PRINCIPAL_INVESTIGATOR
References: