Effect of Hyperbaric Oxygen Therapy on Microcirculation

Not Applicable

Completed

• Conditions: Hyperbaric Oxygen Therapy
• Interventions: Procedure: Hyperbaric oxygen therapy

• Registration Number: NCT03980210
• Lead Sponsor: University Hospital, Lille

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.

Study Timeline

• Study First Submitted: 2019-05-15
• Study First Submitted QC: 2019-06-05
• Study First Posted: 2019-06-10
• Study Start: 2019-06-14
• Primary Completion: 2019-07-25
• Study Completion: 2019-07-25
• Status Verified: 2019-09
• Last Update Submitted: 2019-09-26
• Last Update Posted: 2019-09-27

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 15

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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Hyperbaric oxygen therapy	Hyperbaric oxygen therapy	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

Primary Outcome Measures

Name	Time	Method
Changes in proportion of perfused vessel (PPV)	30 minutes after hyperbaric hyperoxia exposure (FiO2 1 - 2.5 ATA)	Proportion of perfused vessel assessed by Sidestream dark field microscopy on the sublingual mucosa

Secondary Outcome Measures

Name	Time	Method
Changes in area of hyperaemia after a vaso-occlusion test	30 minutes after FiO2 1 - 2.5 ATA exposure	Area under curve assessed by Laser-Doppler
Validation of cardiac output assessed by bioimpedancemetry under hyperbaric condition	30 minutes after FiO2 1 - 2.5 ATA exposure	Comparison with transthoracic echocardiography
Changes in proportion of perfused vessel (PPV)	30 minutes after FiO2 0.21 - 2.5 ATA exposure	Proportion of perfused vessel assessed by Sidestream dark field microscopy on the sublingual mucosa
Changes in hyperemic reaction after a vaso-occlusion test	30 minutes after FiO2 1 - 2.5 ATA exposure	Area under curve assessed by near-infrared spectroscopy

Trial Locations

Locations (1)

Hôpital Roger Salengro, CHU; 🇫🇷 Lille, France