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Reduction of Venous Emboli Load After Breathing Normobaric Oxygen Compared to Air

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ClinicalTrials.gov Identifier: NCT02468752
Recruitment Status : Completed
First Posted : June 11, 2015
Last Update Posted : August 6, 2019
Sponsor:
Collaborators:
Swedish Armed Forces Diving and Naval Medicine Centre
KTH Royal Institute of Technology
Sahlgrenska University Hospital, Sweden
Information provided by (Responsible Party):
Nicklas Oscarsson, Göteborg University

Brief Summary:

Primary objective:

- Assessment of venous gas emboli load post diving when breathing normobaric oxygen compared to air.

Secondary objectives:

  • Assessment of flammatory activity in blood post diving
  • Assessment of fluid markers of central nervous system injury in blood post diving
  • Assessment of DCS frequency
  • Comparison of TCD and TTD consistency in venous gas emboli measurements

Condition or disease Intervention/treatment Phase
Hyperbaric Diving Medicine Decompression Sickness Inflammatory Activity Central Nervous Injury Drug: Oxygen Other: Air Phase 2 Phase 3

Detailed Description:

This is a prospective, double blinded, randomized and controlled, cross-over study in Sweden.

The study will be performed in four different sets, each containing standardized dives in a wet hyperbaric chamber. The dives include movement on depth.

In each study set 10-20 professional divers from the Swedish navy will perform no-decompression dives. The gas used during the dives is compressed air.

After surfacing the divers will breathe either normobaric oxygen or normobaric air on a demand mask. Timing and duration of oxygen/air-breathing will differ between study sets. The content of breathing gas will be unknown to both divers and examining personnel.

Immediately post dive the divers will be assessed using TTD and TTE to determine VGE load, time to VGE detection and VGE duration. In Set 4 measurements will be done after the second dive.

Signs of DCS will be actively sought. TTD measurements will be done every five min during the first 30 min, thereafter every 15 min during 90 min.

TTE will be performed every 30 min, using an apical 4-chamber view. Blood samples will be drawn predive, 30 minutes postdive and 120 minutes postdive.

Set 1: 10-20 divers, divided into two equal groups (A and B). Dive to 42 msw during 10 min with a safety stop at five msw during three min. Immediately post dive breathing of oxygen (group A) or air (group B) during 30 min. VGE load, time to VGE detection and VGE duration is recorded. Blood samples will be drawn pre dive and two hours post dive. After at least 48 hours, the dive is repeated with switched gases between the groups.

Set 2: 10-20 divers, divided into two equal groups (A and B). Dive to 42 msw during 10 min with a safety stop at five msw during three min. Ten minutes post dive breathing of oxygen (group A) or air (group B) during 30 min. VGE load, time to VGE detection and VGE duration is recorded. Blood samples will be drawn pre dive and two hours post dive. After at least 48 hours, the dive is repeated with switched gases between the groups.

Set 3: 10-20 divers, divided into two equal groups (A and B). Dive to 42 msw during 10 min with a safety stop at five msw during three min. Immediately post dive breathing of oxygen (group A) or air (group B) during 15 min. VGE load, time to VGE detection and VGE duration is recorded. Blood samples will be drawn pre dive and two hours post dive. After at least 48 hours, the dive is repeated with switched gases between the groups.

Set 4: 10-20 divers, divided into two equal groups (A and B). First a dive 42 msw during 10 min with a safety stop at five msw during three min. Immediately post dive breathing of oxygen (group A) or air (group B) during 30 min. After a surface interval of 150 min there will be a second dive 33 msw during 12 min. VGE load, time to VGE detection and VGE duration after the second dive is recorded. After at least 48 hours, the two dives are repeated with switched gases between the groups. Blood samples will be drawn before the first dive and two hours after the second dive.

AE including SAE will be recorded during the study. DCS may be considered either an AE or SAE depending on severity. Ongoing AE and SAE will be followed up.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 16 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple (Participant, Care Provider, Investigator)
Primary Purpose: Prevention
Official Title: Mängden kvävgasbubblor i Blodet Efter Dykning Vid Syrgasandning jämfört Med Luftandning
Actual Study Start Date : May 2015
Actual Primary Completion Date : April 2019
Actual Study Completion Date : April 2019

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Oxygen Therapy

Arm Intervention/treatment
Sham Comparator: Air
Normobaric air breathing
Other: Air
Experimental: Oxygen
Normobaric oxygen breathing
Drug: Oxygen



Primary Outcome Measures :
  1. Venous gas emboli [ Time Frame: 150 minutes ]
    Kisman-Masurel grading


Secondary Outcome Measures :
  1. Inflammatory activity [ Time Frame: 120 minutes ]
    E.g. VCAM-1, ICAM-1

  2. Decompression sickness [ Time Frame: 24 hours ]
    Clinical diagnosis

  3. Markers of central nervous system injury [ Time Frame: 120 minutes/48-72 hours ]
    E.g. GFAP, Tau, NfL, JCHL-1



Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 65 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Professional diver
  • Fit to dive according to Swedish Navy standards

Exclusion Criteria:

  • NONE

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02468752


Locations
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Sweden
Sahlgrenska University Hospital
Gothenburg, Sweden, S-416 85
Kungliga Tekniska Högskolan
Stockholm, Sweden, S-100 44
Sponsors and Collaborators
Göteborg University
Swedish Armed Forces Diving and Naval Medicine Centre
KTH Royal Institute of Technology
Sahlgrenska University Hospital, Sweden
Investigators
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Principal Investigator: Mikael Gennser, PhD Kungliga Tekniska Högskolan, Stockholm, Sweden
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Responsible Party: Nicklas Oscarsson, MD, Göteborg University
ClinicalTrials.gov Identifier: NCT02468752    
Other Study ID Numbers: DYK 14-16
First Posted: June 11, 2015    Key Record Dates
Last Update Posted: August 6, 2019
Last Verified: August 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Additional relevant MeSH terms:
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Decompression Sickness
Barotrauma
Wounds and Injuries