Effect of Hyperbaric Oxygen Therapy on Microcirculation

Overview

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 Title of Study: “Effect of Hyperbaric Oxygen Therapy on Healthy Volunteers Microcirculation”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: N/A
    • Intervention Model: Single Group Assignment
    • Primary Purpose: Basic Science
    • Masking: None (Open Label)
  • Study Primary Completion Date: July 25, 2019

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.

Interventions

  • Procedure: Hyperbaric oxygen therapy
    • FiO2 0.21 – 1 ATA FiO2 1 – 1 ATA FiO2 1 – 2.5 ATA FiO2 0.21 – 2.5 ATA FiO2 0.21 – 1 ATA

Arms, Groups and Cohorts

  • Experimental: Hyperbaric oxygen therapy
    • Successive changes in fraction of inspired oxygen and barometric pressure (ATA: Atmosphere absolute) Five successive steps: FiO2 0.21 – 1 ATA FiO2 1 – 1 ATA FiO2 1 – 2.5 ATA FiO2 0.21 – 2.5 ATA FiO2 0.21 – 1 ATA

Clinical Trial Outcome Measures

Primary Measures

  • Changes in proportion of perfused vessel (PPV)
    • Time Frame: 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 Measures

  • Changes in proportion of perfused vessel (PPV)
    • Time Frame: 30 minutes after FiO2 1 – 1 ATA exposure
    • Proportion of perfused vessel assessed by Sidestream dark field microscopy on the sublingual mucosa
  • Changes in proportion of perfused vessel (PPV)
    • Time Frame: 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
    • Time Frame: 30 minutes after FiO2 1 – 2.5 ATA exposure
    • Area under curve assessed by near-infrared spectroscopy
  • Changes in area of hyperaemia after a vaso-occlusion test
    • Time Frame: 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
    • Time Frame: 30 minutes after FiO2 1 – 2.5 ATA exposure
    • Comparison with transthoracic echocardiography

Participating in This Clinical Trial

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

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 64 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • University Hospital, Lille
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Thibault Duburcq, MD, Principal Investigator, University Hospital, Lille

Clinical trials entries are delivered from the US National Institutes of Health and are not reviewed separately by this site. Please see the identifier information above for retrieving further details from the government database.

At TrialBulletin.com, we keep tabs on over 200,000 clinical trials in the US and abroad, using medical data supplied directly by the US National Institutes of Health. Please see the About and Contact page for details.