Mängden kvävgasbubblor i Blodet Efter Dykning Vid Syrgasandning jämfört Med Luftandning
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.
Condition:
Hyperbaric
Treatment:
Oxygen
Start Date:
May 2015
Sponsor:
Göteborg University
For More Information:
https://clinicaltrials.gov/show/NCT02468752